As filed with the Securities and Exchange Commission on September 9, 2021

Registration No. 333-                    

UNITED STATES SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM S-1

REGISTRATION STATEMENT UNDER THE

SECURITIES ACT OF 1933

CFSB Bancorp, Inc. and

Colonial Federal Savings Bank 401(k) Plan

(Exact Name of Registrant as Specified in Its Charter)

15 Beach Street

Quincy, Massachusetts 02170

(617) 471-0750

(Address, Including Zip Code, and Telephone Number, Including Area Code, of Registrant’s Principal Executive Offices)

Michael E. McFarland

President and Chief Executive Officer

15 Beach Street

Quincy, Massachusetts 02170

(617) 471-0750

(Address, Including Zip Code, and Telephone Number, Including Area Code, of Agent for Service)

Copies to:

Approximate date of commencement of proposed sale to the public: As soon as practicable after this registration statement becomes effective.

If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, check the following box: ☒

If this Form is filed to register additional shares for an offering pursuant to Rule 462(b) under the Securities Act, please check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering: ☐

If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering: ☐

If this Form is a post-effective amendment filed pursuant to Rule 462(d) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering: ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company” and “emerging growth company” in Rule 12b-2 of the Exchange Act.:

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided to Section 7(a)(2)(B) of the Securities Act. 9

CALCULATION OF REGISTRATION FEE

The registrant hereby amends this registration statement on such date or dates as may be necessary to delay its effective date until the registrant shall file a further amendment which specifically states that this registration statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933 or until the registration statement shall become effective on such date as the Securities and Exchange Commission, acting pursuant to said Section 8(a), may determine.

Prospectus Supplement

Interests in

COLONIAL FEDERAL SAVINGS BANK

401(k) PLAN

Offering of Participation Interests in up to 632,188 Shares of

CFSB BANCORP, INC.

Common Stock

CFSB Bancorp, Inc. is offering shares of common stock for sale at $10.00 per share in connection with the reorganization of Colonial Federal Savings Bank, a federal mutual savings bank headquartered in Quincy, Massachusetts, into the mutual holding company form of organization and the related minority stock offering of CFSB Bancorp, Inc., the proposed holding company of Colonial Federal Savings Bank. Following the reorganization and minority stock offering, it is expected that shares of CFSB Bancorp, Inc. will be listed on Nasdaq Capital Market under the symbol [symbol].

In connection with the reorganization of Colonial Federal Savings Bank and the related minority stock offering of CFSB Bancorp, Inc., CFSB Bancorp, Inc. and Colonial Federal Savings Bank are offering participants in the Colonial Federal Savings Bank 401(k) Plan (the “401(k) Plan”) the opportunity to invest up to 75% of their 401(k) Plan account balances in the common stock of CFSB Bancorp, Inc. Based upon the value of the 401(k) Plan assets as of August 1, 2021, the trustee of the 401(k) Plan could purchase up to 632,188 shares of CFSB Bancorp, Inc. common stock, at the purchase price of $10.00 per share. This prospectus supplement relates to the election of 401(k) Plan participants to direct the trustee of the 401(k) Plan to invest up to 75% of their 401(k) Plan account balances in the CFSB Bancorp, Inc. Stock Fund at the time of the stock offering. Your ownership interest in the CFSB Bancorp, Inc. Stock Fund will be denominated in units.

Before you consider investing, you should read the prospectus of CFSB Bancorp, Inc. dated [date], which is attached to this prospectus supplement. It contains detailed information regarding the reorganization, stock offering of CFSB Bancorp, Inc. and the financial condition, results of operations and business of Colonial Federal Savings Bank. This prospectus supplement provides information regarding the 401(k) Plan. You should read this prospectus supplement together with the prospectus and keep both for future reference.

For a discussion of risks that you should consider, see “Risk Factors” on page 1 of this prospectus supplement and beginning on page [#] of the attached prospectus, and “Notice of Your Rights Concerning Employer Securities” in this prospectus supplement.

The interests in the 401(k) Plan and the offering of the shares of CFSB Bancorp, Inc. common stock have not been approved or disapproved by the Office of the Comptroller of the Currency, the Board of Governors of the Federal Reserve System, the Federal Deposit Insurance Corporation, the Securities and Exchange Commission or any other federal or state agency. Any representation to the contrary is a criminal offense.

The securities offered by this prospectus supplement are not deposits or savings accounts and are not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.

This prospectus supplement may be used only in connection with offers and sales by CFSB Bancorp, Inc. in the stock offering of CFSB Bancorp, Inc. common stock that may be acquired by the 401(k) Plan. No one may use this prospectus supplement to reoffer or resell interests in shares of CFSB Bancorp, Inc. common stock acquired through the 401(k) Plan.

You should rely only on the information contained in this prospectus supplement and the prospectus. CFSB Bancorp, Inc., Colonial Federal Savings Bank and the 401(k) Plan have not authorized anyone to provide you with different information.

This prospectus supplement does not constitute an offer to sell or solicitation of an offer to buy any securities in any jurisdiction to any person to whom it is unlawful to make an offer or solicitation in that jurisdiction. Neither the delivery of this prospectus supplement and the accompanying prospectus nor any sale of CFSB Bancorp, Inc. common stock shall under any circumstances imply that there has been no change in the affairs of CFSB Bancorp, Inc., Colonial Federal Savings Bank or the 401(k) Plan since the date of this prospectus supplement, or that the information contained in this prospectus supplement or incorporated by reference is correct as of any time after the date of this prospectus supplement.

The date of this prospectus supplement is [date].

TABLE OF CONTENTS

RISK FACTORS

In addition to considering the material risks disclosed under “Risk Factors” beginning on page [#] of the attached prospectus, you should also consider the following:

If you elect to purchase CFSB Bancorp, Inc. common stock using your 401(k) Plan account balance and the stock offering is oversubscribed, you will bear the risk of price changes in the investment funds of the 401(k) Plan.

If you elect to purchase CFSB Bancorp, Inc. common stock using your 401(k) Plan account balance, the 401(k) Plan trustee will sell the designated dollar amount within your 401(k) Plan account pro rata among your investment fund balances. If the stock offering is oversubscribed (i.e., there are more orders for CFSB Bancorp, Inc. common stock than shares available for sale in the stock offering) and the 401(k) Plan trustee cannot use any or all of the funds you allocate to purchase CFSB Bancorp, Inc. common stock, the funds that cannot be invested in CFSB Bancorp, Inc. common stock, and any interest earned on those funds, will be reinvested in your existing investment funds of the 401(k) Plan, according to your then existing investment election in proportion to your investment direction for future contributions. During the period from when the 401(k) Plan trustee sells a portion of each of your investment funds until reinvestment of some or all of those funds back into your investment funds as a result of an oversubscription, you will bear the risk of price changes in the investment funds. It is possible that during this period some or all of the investment funds may have increased in value more than the amount of any interest you may have earned on the reinvested funds before reinvestment. See “The Offering – Purchases in the Stock Offering and Oversubscriptions” in this prospectus supplement.

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THE OFFERING

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DESCRIPTION OF THE PLAN

Introduction

Colonial Federal Savings Bank originally adopted the Colonial Federal Savings Bank 401(k) Plan (the “401(k) Plan”) effective as of October 1, 1984. To facilitate the opportunity for purchase of common stock in the stock offering, a new, single employer plan, which is an amendment and restatement of the original plan, was established effective August 1, 2021. The 401(k) Plan is a tax-qualified plan with a cash or deferred compensation feature established in accordance with the requirements under Section 401(a) and Section 401(k) of the Internal Revenue Code of 1986, as amended (the “Code”).

Colonial Federal Savings Bank intends that the 401(k) Plan, in operation, will comply with the requirements under Section 401(a) and Section 401(k) of the Code. Colonial Federal Savings Bank will adopt any amendments to the 401(k) Plan that may be necessary to ensure the continuing qualified status of the 401(k) Plan under the Code and applicable Treasury Regulations.

Employee Retirement Income Security Act (“ERISA”). The 401(k) Plan is an “individual account plan” other than a “money purchase pension plan” within the meaning of ERISA. As such, the 401(k) Plan is subject to all of the provisions of Title I (Protection of Employee Benefit Rights) and Title II (Amendments to the Code Relating to Retirement Plans) of ERISA, except for the funding requirements contained in Part 3 of Title I of ERISA which by their terms do not apply to an individual account plan (other than a money purchase plan). The 401(k) Plan is not subject to Title IV (Plan Termination Insurance) of ERISA. The funding requirements contained in Title IV of ERISA are not applicable to participants or beneficiaries under the 401(k) Plan.

Reference to Full Text of Plan. The following portions of this prospectus supplement summarize certain provisions of the 401(k) Plan. They are not complete and are qualified in their entirety by the full text of the 401(k) Plan. Copies of the 401(k) Plan are available to all employees by filing a request with the 401(k) Plan administrator c/o Pentegra Services, Inc., 701 Westchester Avenue, Suite 320E, White Plains, New York 10604; (800) 872-3473. You are urged to read carefully the full text of the 401(k) Plan.

Eligibility and Participation

Employees of Colonial Federal Savings Bank who have worked at least 500 hours during a six consecutive month period are eligible to enter the 401(k) Plan on the first day of the next month following the date on which the employee satisfies this eligibility requirement. All employees except for union employees, nonresident aliens and leased employees are eligible to participate in the 401(k) Plan upon meeting the eligibility requirements. The “Plan Year” is January 1 to December 31.

As of August 1, 2021, there were approximately 23 individuals eligible to participate in the 401(k) Plan.

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Contributions Under the Plan

Salary Deferrals. Eligible employees may elect to defer, on a pre-tax basis, up to 50% of their compensation under the 401(k) Plan, subject to certain restrictions imposed by the Code, and to have that amount contributed to the 401(k) Plan on their behalf. Participant’s may further elect to designate salary deferrals as pre-tax contributions or after-tax Roth contributions. For purposes of the 401(k) Plan, “compensation” means a participant’s total wages received from Colonial Federal Savings Bank, with all pre-tax contributions added, that are reported on a Form W-2. “Compensation” includes a participant’s total taxable wages or salary, including any salary deferrals under the 401(k) Plan or any other pre-tax salary reduction contributions made to any other plans maintained by Colonial Federal Savings Bank, but excludes bonuses and commissions. In 2021, the annual compensation of each participant taken into account under the 401(k) Plan is limited to $290,000. (Limits established by the Internal Revenue Service are subject to increase pursuant to an annual cost-of-living adjustment, as permitted by the Code). Participants may elect to modify the amount contributed to the 401(k) Plan by filing a new elective deferral agreement with the 401(k) Plan administrator at the beginning of the next payroll period.

Employer Matching Contributions. Colonial Federal Savings Bank currently makes matching contributions to the 401(k) Plan, equal to 20% of the amount deferred on the first 3% of the participant’s plan compensation.

Discretionary Employer Contributions. Colonial Federal Savings Bank may make discretionary employer contributions to the 401(k) Plan.

Rollover Contributions. Eligible employees may make rollover contributions to the 401(k) Plan.

Limitations on Contributions

Limitations on Employee Salary Deferrals. For the Plan Year beginning January 1, 2021, the amount of a participant’s before-tax contributions may not exceed $19,500 per calendar year. In addition, if a participant is at least 50 years old in 2021, the participant will be able to make a “catch-up” contribution of up to $6,500 in addition to the $19,500 limit. The “catch-up” contribution limit may be adjusted periodically by law, based on changes in the cost of living. Contributions in excess of these limits are known as excess deferrals. Deferred amounts in excess of these limitations, as applicable to a participant, the participant’s gross income for federal income tax purposes will include the excess in the year of the deferral. In addition, unless the excess deferral is distributed before April 15 of the following year, it will be taxed again in the year distributed. Income on the excess deferral distributed by April 15 of the immediately succeeding year will be treated, for federal income tax purposes, as earned and received by a participant in the tax year in which the contribution is made.

Contribution Limit. Generally, the law imposes a maximum limit on the amount of contributions a participant may receive under the 401(k) Plan. This limit applies to all contributions to the 401(k) Plan, including salary deferrals and all other employer contributions made on the participant’s behalf during the year, excluding earnings and any transfers/rollovers. For the Plan Year beginning January 1, 2021, this total cannot exceed the lesser of $58,000 or 100% of a participant’s annual base compensation.

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Benefits Under the Plan

Vesting. At all times, participants have a fully vested, nonforfeitable interest in the salary deferrals made to the 401(k) Plan. Employer matching contributions are subject to a four-year vesting schedule such that a participant will become 25% vested after one year of service, 50% vested after two years of service, 75% after three years of service and 100% after four years of service. In the event of a participant’s death, disability, or attainment of the normal retirement age (age 65), all the employer contributions made on the participant’s behalf would immediately become 100% vested.

Withdrawals and Distributions from the Plan

Applicable federal law requires the 401(k) Plan to impose substantial restrictions on the right of a Plan participant to withdraw amounts held for his or her benefit under the 401(k) Plan prior to the participant’s termination of employment with the employer.

Withdrawals upon Termination. A participant may request a distribution from their account following termination of employment. Following termination of employment, a participant may elect to leave their account balance in the 401(k) Plan and defer commencement of receipt of their vested balance until no later than April 1 of the calendar year following the calendar year in which the participant attains age 72. Notwithstanding the foregoing, if the value of the participant’s vested account balance does not exceed $5,000, the vested account balance will be distributed from the 401(k) Plan, whether or not the participant consents.

Withdrawal upon Disability. If a participant becomes disabled in accordance with the definition of disability under the 401(k) Plan, the participant will be entitled to the same withdrawal rights as if the participant had terminated employment.

Withdrawal upon Death. If a participant dies while a participant in the 401(k) Plan, the value of the participant’s entire account will be payable to the participant’s beneficiary in accordance with the 401(k) Plan.

In-Service Distribution. While employed, participants are eligible to receive an in-service distribution from their account after they attain age 59¹⁄₂ and have participated in the 401(k) Plan for at least five years. Participants are eligible to request a distribution of their rollover contributions at any time.

Hardship. In the event a participant incurs a financial hardship, the participant may request an in-service withdrawal of a portion of their Plan account attributable to salary deferrals.

Participant Loans. Participant loans are allowed in accordance with the 401(k) Plan’s participant loan procedures.

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Form of Distribution. Distributions are made from the 401(k) Plan in a single lump-sum payment.

Investment of Contributions and Account Balances

All amounts credited to your account under the 401(k) Plan are held in the 401(k) Plan trust, which is administered by the trustee of the 401(k) Plan. Prior to the effective date of the stock offering, you are currently provided the opportunity to direct the investment of your account into the following investment options:

In connection with the stock offering, the 401(k) Plan now provides that in addition to the investment options specified above, you may direct the trustee, or its representative, to invest a portion of your account balance in shares of CFSB Bancorp, Inc. common stock.

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Performance History and Description of Funds

The following provides performance data with respect to the investment options available under the 401(k) Plan:

The following is a description of each of the 401(k) Plan’s investment funds and other investments:

MetLife Stable Value Fund. This is a stable value offering that is designed to provide safety and preservation of principal and accumulated interest for participant-initiated transactions. The interest credited to balances in the fund will reflect both current market conditions and performance of the underlying investments in the fund. MetLife provides the book value wrapper for this fund. The fund typically uses a multi-manager approach for investing its assets in a combination of fixed-income securities and guaranteed interest contracts.

SSgA U.S. Inflation Protected Bond Index NL Fund. This passively managed fund seeks to offer broad, low-cost exposure to U.S. Treasury bonds that automatically adjust to protect from increases in inflation. Further, the fund seeks an investment return that approximates as closely as practicable, before expenses, the performance of the Barclays U.S. Treasury Inflation Protected Securities (TIPS) Index over the long term. The manager will typically attempt to invest in the equity securities comprising the index, in approximately the same proportions as they are represented in the index. However, due to the diverse composition of securities in the index and the fact that many of the securities comprising the index may be unavailable for purchase, it may not be possible for the fund to purchase some of the securities. In such a case, the manager will select securities for the fund that the manager expects will provide a comparable return.

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SSgA U.S. Bond Index NL Fund. This fixed-income fund is passively managed (indexed) and seeks to offer broadly diversified, low-cost exposure to the overall U.S. bond market. The fund seeks an investment return that approximates as closely as practicable, before expenses, the performance of the Bloomberg Barclays U.S. Aggregate Bond Index over the long term. The fund will not necessarily own all of the securities included in the index.

SSgA Russell Large Cap Growth Index NL Fund. This is a passively managed, large-cap growth fund that seeks to offer broad low-cost exposure to large U.S. growth stocks. The fund seeks an investment return that approximates as closely as practicable, before expenses, the performance of the Russell 1000 Growth Index over the long term. The manager will typically attempt to invest in the equity securities comprising the index, in approximately the same proportions as they are represented in the index.

SSgA Russell Large Cap Value Index NL Fund. This is a passively managed, large-cap value fund that seeks to offer broad low-cost exposure to large U.S. value stocks. The fund seeks an investment return that approximates as closely as practicable, before expenses, the performance of the Russell 1000 Value Index over the long term. The manager will typically attempt to invest in the equity securities comprising the index, in approximately the same proportions as they are represented in the index.

SSgA S&P 500 Index NL Fund. This is a passively managed, large-cap core fund. The fund seeks an investment return that approximates as closely as practicable, before expenses, the performance of the S&P 500 Index over the long term. The manager will typically attempt to invest in the equity securities comprising the index, in approximately the same proportions as they are represented in the index.

SSgA S&P Mid Cap Index NL Fund. This passively managed, midcap blend fund seeks to offer broad, low-cost exposure to stocks of medium sized U.S. companies. Further, the fund seeks an investment return that approximates as closely as practicable, before expenses, the performance of the S&P MidCap 400 Index over the long term. The manager will typically attempt to invest in the equity securities comprising the index, in approximately the same proportions as they are represented in the index.

SSgA Russell Small Cap Index NL Fund. This passively managed, small-cap blend fund seeks to offer broad, low-cost exposure to stocks of small U.S. companies. Further, the fund seeks an investment return that approximates as closely as practicable, before expenses, the performance of the Russell 2000 Index over the long term. The manager will typically attempt to invest in the equity securities comprising the index, in approximately the same proportions as they are represented in the index.

SSgA REIT Index NL Fund. This is a passively managed fund that seeks to offer broad, low-cost exposure to the U.S. commercial real estate securities market. The fund seeks an investment return that approximates as closely as practicable, before expenses, the performance of the Dow Jones U.S. Select REIT Index, over the long term. The manager will typically attempt to invest in the equity securities comprising the index, in approximately the same proportions as they are represented in the index.

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SSgA International Index NL Fund. This non-U.S. equity fund seeks to offer broad, low-cost exposure to international stocks of companies in the developed markets of Europe, Australasia, and the Far East. The fund seeks an investment return that approximates as closely as practicable, before expenses, the performance of the MSCI EAFE Index over the long term. The manager will typically attempt to invest in the equity securities comprising the index, in approximately the same proportions as they are represented in the index. In some cases, it may not be possible or practicable to purchase all of the securities comprising the index, or to hold them in the same weightings as they represent in the index. In those circumstances, the manager may employ a sampling or optimization technique to construct the portfolio.

SSgA Strategic Balanced Funds series (Conservative, Moderate, Aggressive). This series includes three funds with different equity and fixed-income mixes designed to appeal to investors with varying risk tolerances (conservative, moderate and aggressive), with a focus ranging from income to aggressive growth. The funds seek to offer broad diversification and a disciplined rebalancing process. The more conservative fund has a greater allocation to fixed-income relative to the other funds, whereas the more aggressive fund has a greater percentage of assets allocated to equities. The underlying funds within each of the Strategic Balanced Funds are index funds managed by SSgA.

SSgA Target Retirement Funds. The funds seek to offer complete, low-cost investment strategies with asset allocations which become more conservative as investors near retirement. Each fund in the series seeks an investment return that approximates as closely as practicable, before expenses, the performance of a custom benchmark index over the long term. Each fund seeks to achieve its objective by investing in a set of underlying SSgA collective trust funds representing various asset classes. Each fund (other than the Target Retirement Income Fund) is managed to a specific retirement year (target date) included in its name. Over time, the allocation to asset classes and funds change according to a predetermined “glide path”. (The glide path represents the shifting of asset classes over time and does not apply to the Income Fund.) Each fund’s asset allocation will become more conservative as it approaches its target retirement date.

Once a fund reaches its target retirement date, it will begin a five-year transition period to the Target Retirement Income Fund. At the end of that five-year period, the allocation to stocks, real estate investment trusts and commodities interests exposure will remain fixed at approximately 35% of assets. The remainder of the fund will be invested in fixed-income securities.

Investors should carefully consider a mutual fund’s investment objectives, risks, charges, and expenses prior to investing. A prospectus, or summary prospectus if available, containing this and other information can be obtained by contacting the 401(k) Plan administrator. Read the prospectus carefully before investing.

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Before directing retirement funds to a separate account, investors should carefully consider the investment objectives, risks, charges, and expenses of the separate account as well as their individual risk tolerance, time horizon and goals. For additional information, contact the 401(k) Plan administrator.

CFSB Bancorp, Inc. Stock Fund. In connection with the stock offering, you may, in the manner described earlier, direct the trustee to invest up to 75% of your 401(k) Plan account balance in CFSB Bancorp, Inc. common stock. The trustee will use all amounts elected by participants to acquire shares of CFSB Bancorp, Inc. common stock in the reorganization and common stock offering. Your purchased shares will be held within the 401(k) Plan by the CFSB Bancorp, Inc. Stock Fund. The CFSB Bancorp, Inc. Stock Fund is neither a mutual fund nor a diversified or managed investment option. Rather, it is merely a recordkeeping mechanism established by the 401(k) Plan custodian to track the shares purchased by the participants in the stock offering through the 401(k) Plan. The CFSB Bancorp, Inc. Stock Fund will consist solely of shares of CFSB Bancorp, Inc. common stock purchased by participants in the 401(k) Plan, which will be initially valued at $10.00 per share (i.e., the purchase price). Your interest in the CFSB Bancorp, Inc. Stock Fund will be denominated in shares of CFSB Bancorp, Inc. common stock. After the stock offering, the 401(k) Plan will also maintain a Stock Liquidity Fund. New contributions or transfers of funds into the CFSB Bancorp, Inc. Stock Fund will first be held in the Stock Liquidity Fund. Once the shares are purchased, they will be transferred into the CFSB Bancorp, Inc. Stock Fund.

As of the date of this prospectus supplement, there is no established market for CFSB Bancorp, Inc. common stock. Accordingly, there is no record of the historical performance of the CFSB Bancorp, Inc. Stock Fund. Performance of the CFSB Bancorp, Inc. Stock Fund depends on several factors, including the financial condition and profitability of CFSB Bancorp, Inc. and Colonial Federal Savings Bank and market conditions for shares of CFSB Bancorp, Inc. common stock generally.

Investment in CFSB Bancorp, Inc. common stock involves risks common to investments in the shares of stock. For a discussion of material risks you should consider, see “Risk Factors: of this prospectus supplement, “Risk Factors” beginning on page [#] of the attached prospectus, and the section of this prospectus supplement called “Notice of Your Rights Concerning Employer Securities” below.

You may elect to have both past contributions and earnings, as well as future contributions to your account invested among the options listed above, including the CFSB Bancorp, Inc. Stock Fund. Transfers of past contributions and the earnings thereon do not affect the investment mix of future contributions. You may change your investment directions at any time.

An investment in any of the funds listed above is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. As with any mutual fund investment, there is always a risk that you may lose money on your investment in any of the funds listed above. Please note that the MetLife Stable Value Fund is not a mutual fund, but rather a capital preservation fund.

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Administration of the Plan

The Trustee and Custodian. Pentegra Trust Company serves as trustee of, and Reliance Trust Company as custodian for all the investment funds under, the 401(k) Plan. Pentegra Trust Company serves as directed trustee for the CFSB Bancorp, Inc. Stock Fund

Plan Administrator. Pursuant to the terms of the 401(k) Plan, the 401(k) Plan is administered by Pentegra Services, Inc. The address of the 401(k) Plan administrator is 701 Westchester Avenue, Suite 320E, White Plains, New York 10604, telephone number is (800) 872-3473. The 401(k) Plan administrator is responsible for the administration of the 401(k) Plan, interpretation of the provisions of the 401(k) Plan, prescribing procedures for filing applications for benefits, preparation and distribution of information explaining the 401(k) Plan, maintenance of Plan records, books of account and all other data necessary for the proper administration of the 401(k) Plan, preparation and filing of all returns and reports relating to the 401(k) Plan which are required to be filed with the U.S. Department of Labor and the Internal Revenue Service, and for all disclosures required to be made to participants, beneficiaries and others under Sections 104 and 105 of ERISA.

Reports to Plan Participants. The 401(k) Plan administrator will furnish you a statement at least quarterly showing the balance in your account as of the end of that period, the amount of contributions allocated to your account for that period, and any adjustments to your account to reflect earnings or losses (if any).

Amendment and Termination

It is the intention of Colonial Federal Savings Bank to continue the 401(k) Plan indefinitely. Nevertheless, Colonial Federal Savings Bank may terminate the 401(k) Plan at any time. If the 401(k) Plan is terminated in whole or in part, then regardless of other provisions in the 401(k) Plan, you will have a fully vested interest in your account. Colonial Federal Savings Bank reserves the right to make any amendment or amendments to the 401(k) Plan which do not cause any part of the trust to be used for, or diverted to, any purpose other than the exclusive benefit of participants or their beneficiaries; provided, however, that Colonial Federal Savings Bank may make any amendment it determines necessary or desirable, with or without retroactive effect, to comply with ERISA.

Merger, Consolidation or Transfer

In the event of the merger or consolidation of the 401(k) Plan with another plan, or the transfer of the trust assets to another plan, the 401(k) Plan requires that you would, if either the 401(k) Plan or the other plan terminates, receive a benefit immediately after the merger, consolidation or transfer which is equal to or greater than the benefit you would have been entitled to receive immediately before the merger, consolidation or transfer, if the 401(k) Plan had then terminated.

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Federal Income Tax Consequences

The following is a brief summary of the material federal income tax aspects of the 401(k) Plan. You should not rely on this summary as a complete or definitive description of the material federal income tax consequences relating to the 401(k) Plan. Statutory provisions change, as do their interpretations, and their application may vary in individual circumstances. Finally, the consequences under applicable state and local income tax laws may not be the same as under the federal income tax laws. Please consult your tax advisor with respect to any distribution from the 401(k) Plan and transactions involving the 401(k) Plan.

As a “tax-qualified retirement plan,” the Code affords the 401(k) Plan special tax treatment, including:

Colonial Federal Savings Bank will administer the 401(k) Plan to comply with the requirements of the Code as of the applicable effective date of any change in the law.

Lump-Sum Distribution. A distribution from the 401(k) Plan to a participant or the beneficiary of a participant will qualify as a lump-sum distribution if it is made within one taxable year, on account of the participant’s death, disability or separation from service, or after the participant attains age 59¹⁄₂, and consists of the balance credited to participants under the 401(k) Plan and all other profit sharing plans, if any, maintained by Colonial Federal Savings Bank. The portion of any lump-sum distribution required to be included in your taxable income for federal income tax purposes consists of the entire amount of the lump-sum distribution, less the amount of after-tax contributions, if any, you have made to this Plan and any other profit sharing plans maintained by Colonial Federal Savings Bank, which is included in the distribution.

CFSB Bancorp, Inc. common stock Included in Lump-Sum Distribution. If a lump-sum distribution includes CFSB Bancorp, Inc. common stock, the distribution generally will be taxed in the manner described above, except that the total taxable amount may be reduced by the amount of any net unrealized appreciation with respect to CFSB Bancorp, Inc. common stock; that is, the excess of the value of CFSB Bancorp, Inc. common stock at the time of the distribution over its cost or other basis of the securities to the trust. The tax basis of CFSB Bancorp, Inc. common stock, for purposes of computing gain or loss on its subsequent sale, equals the value of CFSB Bancorp, Inc. common stock at the time of distribution, less the amount of net unrealized appreciation. Any gain on a subsequent sale or other taxable disposition of CFSB Bancorp, Inc. common stock, to the extent of the amount of net unrealized appreciation at the time of distribution, will constitute long-term capital gain, regardless of the holding period of CFSB Bancorp, Inc. common stock. Any gain on a subsequent sale or other taxable disposition of CFSB Bancorp, Inc.

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common stock, in excess of the amount of net unrealized appreciation at the time of distribution, will be considered long-term capital gain. The recipient of a distribution may elect to include the amount of any net unrealized appreciation in the total taxable amount of the distribution, to the extent allowed by regulations to be issued by the Internal Revenue Service.

Distributions: Rollovers and Direct Transfers to Another Qualified Plan or to an IRA. You may roll over virtually all distributions from the 401(k) Plan to another qualified plan or to an individual retirement account in accordance with the terms of the other plan or account.

Notice of Your Rights Concerning Employer Securities

Federal law provides specific rights concerning investments in employer securities. Because you may in the future have investments in CFSB Bancorp, Inc. common stock under the 401(k) Plan, you should take the time to read the following information carefully.

Your Rights Concerning Employer Securities. The Plan must allow you to elect to move any portion of your account that is invested in CFSB Bancorp, Inc. common stock from that investment into other investment alternatives under the 401(k) Plan. You may contact the 401(k) Plan administrator shown above for specific information regarding this right, including how to make this election. In deciding whether to exercise this right, you will want to give careful consideration to the information below that describes the importance of diversification. All of the investment options under the 401(k) Plan are available to you if you decide to diversify out of your investment in CFSB Bancorp, Inc. common stock.

The Importance of Diversifying Your Retirement Savings. To help achieve long-term retirement security, you should give careful consideration to the benefits of a well-balanced and diversified investment portfolio. Spreading your assets among different types of investments can help you achieve a favorable rate of return, while minimizing your overall risk of losing money. This is because market or other economic conditions that cause one category of assets, or one particular security, to perform very well often cause another asset category, or another particular security, to perform poorly. If you invest more than 20% of your retirement savings in any one company or industry, your savings may not be properly diversified. Although diversification is not a guarantee against loss, it is an effective strategy to help you manage investment risk.

In deciding how to invest your retirement savings, you should take into account all of your assets, including any retirement savings outside of the 401(k) Plan. No single approach is right for everyone because, among other factors, individuals have different financial goals, different time horizons for meeting their goals, and different tolerance for risk. Therefore, you should carefully consider the rights described here and how these rights affect the amount of money that you invest in employer common stock through the 401(k) Plan.

It is also important to periodically review your investment portfolio, your investment objectives, and the investment options under the 401(k) Plan to help ensure that your retirement savings will meet your retirement goals.

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Additional Employee Retirement Income Security Act (“ERISA”) Considerations

As noted above, the 401(k) Plan is subject to certain provisions of ERISA, including special provisions relating to control over the 401(k) Plan’s assets by participants and beneficiaries. The 401(k) Plan’s feature that allows you to direct the investment of your account balances is intended to satisfy the requirements of Section 404(c) of ERISA relating to control over plan assets by a participant or beneficiary. The effect of this is two-fold. First, you will not be deemed a “fiduciary” because of your exercise of investment discretion. Second, no person who otherwise is a fiduciary, such as Colonial Federal Savings Bank, the 401(k) Plan administrator, or the 401(k) Plan’s trustee is liable under the fiduciary responsibility provision of ERISA for any loss which results from your exercise of control over the assets in your 401(k) Plan account.

Because you will be entitled to invest up to 75% of your account balance in the 401(k) Plan in CFSB Bancorp, Inc. common stock, the regulations under Section 404(c) of the ERISA require that the 401(k) Plan establish procedures that ensure the confidentiality of your decision to purchase, hold, or sell employer securities, except to the extent that disclosure of such information is necessary to comply with federal or state laws not preempted by ERISA. These regulations also require that your exercise of voting and similar rights with respect to CFSB Bancorp, Inc. common stock be conducted in a way that ensures the confidentiality of your exercise of these rights.

Securities and Exchange Commission Reporting and Short-Swing Profit Liability

Section 16 of the Securities Exchange Act of 1934 imposes reporting and liability requirements on officers, directors, and persons beneficially owning more than 10% of public companies such as CFSB Bancorp, Inc. Section 16(a) of the Securities Exchange Act of 1934 requires the filing of reports of beneficial ownership. Within 10 days of becoming an officer, director or person beneficially owning more than 10% of the shares of CFSB Bancorp, Inc., a Form 3 reporting initial beneficial ownership must be filed with the Securities and Exchange Commission. Changes in beneficial ownership, such as purchases, sales and gifts generally must be reported periodically, either on a Form 4 within two business days after the change occurs, or annually on a Form 5 within 45 days after the close of CFSB Bancorp, Inc.’s fiscal year. Discretionary transactions in and beneficial ownership of CFSB Bancorp, Inc. common stock by officers, directors and persons beneficially owning more than 10% of CFSB Bancorp, Inc. common stock generally must be reported to the Securities and Exchange Commission by such individuals.

In addition to the reporting requirements described above, Section 16(b) of the Securities Exchange Act of 1934, as amended, provides for the recovery by CFSB Bancorp, Inc. of profits realized by an officer, director or any person beneficially owning more than 10% of CFSB Bancorp, Inc. common stock resulting from non-exempt purchases and sales of CFSB Bancorp, Inc. common stock within any six-month period.

The Securities and Exchange Commission has adopted rules that provide exemptions from the profit recovery provisions of Section 16(b) for all transactions in employer securities within an employee benefit plan, provided certain requirements are met. These requirements generally involve restrictions upon the timing of elections to acquire or dispose of employer securities for the accounts of Section 16(b) persons.

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Except for distributions of CFSB Bancorp, Inc. common stock due to death, disability, retirement, termination of employment or under a qualified domestic relations order, persons affected by Section 16(b) are required to hold shares of CFSB Bancorp, Inc. common stock distributed from the 401(k) Plan for six months following such distribution and are prohibited from directing additional purchases of CFSB Bancorp, Inc. common stock for six months after receiving such a distribution.

Financial Information Regarding Plan Assets

Financial information representing the net assets available for 401(k) Plan benefits and the change in net assets available for 401(k) Plan benefits at August  1, 2021, is available upon written request to the 401(k) Plan administrator at the address shown above.

LEGAL OPINION

The validity of the issuance of CFSB Bancorp, Inc. common stock has been passed upon by Luse Gorman, PC, Washington, D.C., which firm acted as special counsel to Colonial Federal Savings Bank in connection with the stock offering of CFSB Bancorp, Inc.

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PROSPECTUS

CFSB Bancorp, Inc.

(Proposed Holding Company for Colonial Federal Savings Bank)

Up to 2,472,500 Shares of Common Stock

(Subject to increase to up to 2,843,375 shares)

CFSB Bancorp, Inc. is offering up to 2,472,500 shares of its common stock for sale at $10.00 per share on a best efforts basis in connection with the reorganization of Colonial Federal Savings Bank into the mutual holding company form of ownership. In connection with the sale of our common stock and the reorganization, we intend to establish a charitable foundation and contribute 2.0% of the outstanding shares of common stock of CFSB Bancorp, Inc. and $250,000 in cash to the charitable foundation. There is no established market for our common stock. We expect that our common stock will be traded on the Nasdaq Capital Market under the symbol “[ticker]” upon conclusion of the offering. We are an “emerging growth company” as defined in the Jumpstart Our Business Startups Act of 2012.

The shares being offered, including shares issued to the charitable foundation, represent 45.0% of the shares of common stock of CFSB Bancorp, Inc. that will be outstanding following the offering. After the offering, 55.0% of our outstanding common stock will be owned by 15 Beach, MHC, our federally chartered mutual holding company. These percentages will not be affected by the number of shares we sell in the offering. We must sell a minimum of 1,827,500 shares to complete the offering. We may sell up to 2,843,375 shares to reflect demand for the shares or changes in market conditions following the commencement of the offering, without resoliciting subscribers.

We are offering the shares of common stock in a “subscription offering” to eligible depositors of Colonial Federal Savings Bank and to our tax-qualified employee benefit plans. Depositors who had accounts with aggregate balances of at least $50 at the close of business on June 30, 2020 will have first priority to purchase shares of common stock of CFSB Bancorp, Inc. Shares of common stock not purchased in the subscription offering may be offered for sale to the general public in a “community offering.” To the extent any shares offered for sale are not purchased in the subscription or community offerings, they may be sold in a “syndicated community offering” to be managed by Piper Sandler & Co. (“Piper Sandler”).

The minimum number of shares of common stock you may order is 25 shares. The maximum number of shares of common stock that can be ordered by any person in the offering, or persons exercising subscription rights through a single deposit account, is 10,000 shares ($100,000), and no person together with an associate or group of persons acting in concert may purchase more than 15,000 shares ($150,000).

The offering is scheduled to expire at _:00 p.m., Eastern Time, on [EXP DATE]. We may extend the expiration date without notice to you, until [EXT DATE 1], or such later date as the Board of Governors of the Federal Reserve System may approve, which may not be beyond [EXT DATE 2]. Once submitted, orders are irrevocable unless the offering is terminated or extended beyond [EXT DATE 1], or the number of shares of common stock to be sold is increased to more than 2,843,375 shares or decreased to less than 1,827,500 shares. If the offering is extended beyond [EXT DATE 1], all subscribers will be notified and given an opportunity to confirm, cancel or change their orders. If you do not respond to this notice, we will promptly return your funds with interest or cancel your deposit account withdrawal authorization. If the number of shares to be sold in the offering is increased to more than 2,843,375 shares or decreased to less than 1,827,500 shares, we will resolicit subscribers, and all funds delivered to us to purchase shares of common stock in the subscription and community offerings will be returned promptly with interest. Funds submitted for the purchase of shares in the offering will be held in a segregated account at Colonial Federal Savings Bank and will earn interest at 0.10% until completion or termination of the offering.

Piper Sandler will use its best efforts to assist us in selling our common stock, but is not obligated to purchase any of the common stock that is being offered for sale. In addition, our officers, directors and employees may participate in the solicitation of offers to purchase common stock in reliance upon Rule 3a4-1 under the Securities Exchange Act of 1934, as amended. Subscribers will not pay any commissions to purchase shares of common stock in the offering.

OFFERING SUMMARY

Price: $10.00 per share

This investment involves a degree of risk, including the possible loss of principal. Please read the “Risk Factors” beginning on page 18.

These securities are not deposits or savings accounts and are not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. None of the Securities and Exchange Commission, the Board of Governors of the Federal Reserve System, the Office of the Comptroller of the Currency, the Federal Deposit Insurance Corporation nor any state securities regulator has approved or disapproved of these securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

Piper Sandler & Co.

For assistance, please contact the Stock Information Center at 1-(877)          -        .

The date of this prospectus is [Prospectus Date].

[MAP TO BE INSERTED ON INSIDE COVER PAGE]

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RISK FACTORS

Risks Related to the COVID-19 Pandemic

The economic impact of the COVID-19 outbreak could adversely affect our financial condition and results of operations.

The COVID-19 pandemic caused significant economic dislocation in the United States as many state and local governments ordered non-essential businesses to close and residents to shelter in place at home. While most of these restrictions have been removed and businesses have begun to re-open, it is not clear when the pandemic will abate. In response to the COVID-19 outbreak, the Federal Reserve Board has reduced the benchmark federal funds rate to a target range of 0% to 0.25%, and the yields on 10- and 30-year treasury notes declined to historic lows. Certain federal and state agencies are requiring lenders to provide forbearance and other relief to borrowers (e.g., waiving late payment and other fees). The federal banking agencies have encouraged financial institutions to prudently work with affected borrowers and legislation has provided relief from reporting loan classifications due to modifications related to the COVID-19 outbreak. Limitations have been placed on foreclosures during the pandemic. We may take further actions as may be required by government authorities or that we determine are in the best interests of our employees, customers and business partners.

Given the ongoing and dynamic nature of the pandemic, we cannot predict the full impact of the COVID-19 outbreak on our business and on our prospects. The extent of such impact will depend on future developments, which are highly uncertain, including when the pandemic can be controlled and abated and when and how the economy may be fully re-opened. As the result of the COVID-19 pandemic and the related adverse economic consequences, we could be subject to any of the following risks, any of which could have a material, adverse effect on our business, financial condition, liquidity, prospects and results of operations:

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Moreover, our future success and profitability substantially depends on the management skills of our executive officers and directors, some of whom have held officer and director positions with us for many years. The unanticipated loss or unavailability of key employees due to the outbreak could harm our ability to operate our business or execute our business strategy. We may not be successful in finding and integrating suitable successors in the event of key employee loss or unavailability.

Any one or a combination of the factors identified above could negatively impact our business, financial condition and results of operations and prospects.

Risks Related to our Lending Activities

Almost all of our loans are secured by real estate, and a downturn in the local real estate market could negatively impact our profitability.

At June 30, 2021, approximately $174.4 million, or 98.8%, of our total loan portfolio, was secured by real estate, most of which is located in our primary lending market area of Norfolk and Plymouth Counties, Massachusetts and surrounding areas. Future declines in the real estate values in our primary lending markets and surrounding markets because of an economic downturn could significantly impair the value of the particular collateral securing our loans and our ability to sell the collateral upon foreclosure for an amount necessary to satisfy the borrower’s obligations to us. This could require increasing our allowance for loan losses to address the decrease in the value of the real estate securing our loans, which could have a material adverse effect on our business, financial condition, results of operations and growth prospects.

Unlike larger financial institutions that are more geographically diversified, our profitability depends primarily on the general economic conditions in our primary market area. Local economic conditions have a significant impact on our residential real estate and other types of lending, including, the ability of borrowers to repay these loans and the value of the collateral securing these loans.

Moreover, a significant decline in general economic conditions, caused by inflation, acts of terrorism, an outbreak of hostilities or other international or domestic calamities or other factors beyond our control could further impact these local economic conditions and could further negatively affect our financial performance. In addition, deflationary pressures, while possibly lowering our operating costs, could have a significant negative effect on our borrowers, especially our business borrowers, and the values of underlying collateral securing loans, which could negatively affect our financial performance.

If our allowance for loan losses is not sufficient to cover actual loan losses, our earnings could decrease.

We make various assumptions and judgments about the collectability of our loan portfolio, including the creditworthiness of our borrowers and the value of the real estate and other assets serving as collateral for the repayment of many of our loans. In determining the amount of the allowance for loan losses, we review our loans and our loss and delinquency experience, and we evaluate economic conditions. If our assumptions or the results of our analyses are incorrect, our allowance for loan losses may not be sufficient to cover losses inherent in our loan portfolio, resulting in additions to our allowance. In addition, our emphasis on loan growth and on increasing our portfolio of commercial real estate loans, as well as any future credit deterioration, including as a result of COVID-19, could require us to increase our allowance for loan losses in the future. At June 30, 2021, our allowance for loan losses as a percentage of total loans was 0.98%. Material additions to our allowance would materially decrease our net income.

The Financial Accounting Standards Board has delayed the effective date of the implementation of Current Expected Credit Losses, or CECL, standard. CECL will be effective for CFSB Bancorp, Inc. on January 1, 2023. CECL will require financial institutions to determine periodic estimates of lifetime expected credit losses on loans, and recognize the expected credit losses as allowances for credit losses. This will change the current method of providing allowances for loan losses that are incurred or probable, which would likely require us to increase our allowance for credit losses, and to greatly increase the types of data we would need to collect and review to determine the appropriate level of the allowance for credit losses.

In addition, bank regulators periodically review our allowance for loan losses and, as a result of such reviews, we may be required to increase our provision for loan losses or recognize further loan charge-offs. Any increase in our allowance for loan losses or loan charge-offs as a result of such review or otherwise may have a material adverse effect on our financial condition and results of operations.

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We intend to increase the origination of multi-family and commercial real estate loans. These loans involve credit risks that could adversely affect our financial condition and results of operations.

At June 30, 2021, commercial real estate loans totaled $16.4 million, or 9.3% of our loan portfolio and multi-family real estate loans totaled $15.9 million, or 9.0% of our loan portfolio. Given their larger balances and the complexity of the underlying collateral, multi-family and commercial real estate loans generally have more risk than the owner-occupied one- to four-family residential real estate loans that we originate. Because the repayment of multi-family and commercial real estate loans depends on the successful management and operation of the borrower’s properties or related businesses, repayment of such loans can be affected by adverse conditions in the local real estate market or economy. The adverse effects of the COVID-19 pandemic could adversely impact the value of properties securing the loan or the revenues from the borrower’s business, thereby increasing the risk of non-performing loans. If we foreclose on these loans, our holding period for the collateral typically is longer than for a one- to four-family residential property because there are fewer potential purchasers of the collateral. In addition, multi-family and commercial real estate loans typically involve larger loan balances to single borrowers or groups of related borrowers compared to one- to four-family residential loans. Accordingly, charge-offs on multi-family and commercial real estate loans may be larger on a per loan basis than those incurred by our one- to four-family residential real estate or consumer loan portfolios.

As our commercial and multi-family real estate loan portfolio increases, the corresponding risks and potential for losses from these loans may also increase, which would adversely affect our business, financial condition and results of operations.

Our non-owner-occupied one- to four-family residential real estate loans may expose us to increased credit risk.

At June 30, 2021, $20.5 million, or 11.6% of our total loan portfolio, consisted of loans secured by non-owner-occupied one- to four-family residential real estate properties. At June 30, 2021, all of our non-owner-occupied one- to four-family residential real estate loans were performing in accordance with their repayment terms. One- to four-family residential loans secured by non-owner-occupied properties generally expose a lender to greater risk of non-payment and loss than loans secured by owner-occupied properties because repayment of such loans depend primarily on the tenant’s continuing ability to pay rent to the property owner, who is our borrower, or, if the property owner is unable to find a tenant, the property owner’s ability to repay the loan without the benefit of a rental income stream. In addition, the physical condition of non-owner-occupied properties may be below that of owner-occupied properties due to lenient property maintenance standards that negatively impact the value of the collateral properties.

Risks Related to our Business Strategy

Our business strategy includes loan growth, and our financial condition and results of operations could be negatively affected if we fail to grow or fail to manage our growth effectively. Growing our operations could also cause our expenses to increase faster than our revenues.

Our business strategy primarily focuses on loan growth, funded by deposits. Achieving such growth may require us to attract customers that currently bank at other financial institutions in our market area. Our ability to successfully grow will depend on a variety of factors, including our ability to attract and retain experienced bankers, the continued availability of desirable business opportunities, the level of competition from other financial institutions in our market area and our ability to manage our growth. Growth opportunities may not be available or we may not be able to manage our growth successfully. If we do not manage our growth effectively, our financial condition and operating results could be negatively affected. Furthermore, there can be considerable costs involved in opening branches and expanding lending capacity, and generally a period of time is required to generate the necessary revenues to offset these costs, especially in areas in which we do not have an established presence. Accordingly, any such business expansion can be expected to negatively impact our earnings until certain economies of scale are reached. Our expenses could be further increased if we encounter delays in the opening of new branches.

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A significant percentage of our assets is invested in securities, which typically have a lower yield than our loan portfolio.

Our results of operations depend substantially on our net interest income. At June 30, 2021, 43.6% of our assets were invested in investment securities and cash and cash equivalents. These investments yield substantially less than the loans we hold in our portfolio. While we intend to invest a greater proportion of our assets in loans with the goal of increasing our net interest income, we may not be able to increase originations of loans that are acceptable to us. Further, at June 30, 2021, $105.1 million, or 87.9%, of our securities portfolio was designated a held to maturity. As a result, we are unable to sell these securities to respond to changes in interest rates that may occur in the future.

We depend on our management team and other key personnel to implement our business strategy and execute successful operations and we could be harmed by the loss of their services or the inability to hire additional personnel.

We depend on the services of the members of our senior management team who direct our strategy and operations. Our executive officers and lending personnel possess substantial expertise, extensive knowledge of our markets and key business relationships. Any one of them could be difficult to replace. Our loss of these persons, or our inability to hire additional qualified personnel, could impact our ability to implement our business strategy and could have a material adverse effect on our results of operations and our ability to compete in our markets. See “Management.”

Risks Related to Market Interest Rates

A continuation of the historically low interest rate environment and the possibility that we may access higher-cost funds to support our loan growth and operations may adversely affect our net interest income and profitability.

In recent years, the Federal Reserve Board’s policy has been to maintain interest rates at historically low levels through its targeted federal funds rate and the purchase of mortgage-backed securities. Our ability to reduce our interest expense may be limited at current interest rate levels while the average yield on our interest-earning assets may continue to decrease, and our interest expense may increase as we access non-core funding sources or increase deposit rates to fund our operations. A continuation of a low interest rate environment or an increase in our cost of funds may adversely affect our net interest margin and net interest income, which would have an adverse effect on our profitability.

Future changes in interest rates could negatively affect our operating results and asset values.

Net income is the amount by which net interest income and non-interest income exceed non-interest expense and the provision for loan losses. Net interest income makes up a majority of our income and is based on the difference between:

The rates we earn on our assets and the rates we pay on our liabilities are generally fixed for a contractual period of time. Like many savings institutions, our liabilities generally have shorter contractual maturities than our assets. This is exacerbated due to our historical focus on one- to four-family residential real estate loans, the substantial majority of which have fixed interest rates. This imbalance can create significant earnings volatility because market interest rates change over time. In a period of rising interest rates, the interest income we earn on our assets may not increase as rapidly as the interest we pay on our liabilities. Furthermore, increases in interest rates may adversely affect our ability to originate loans and/or the ability of our borrowers to make loan repayments on adjustable-rate loans, as the interest owed on such loans would increase as interest rates increase. In a period of declining interest rates, the interest income we earn on our assets may decrease more rapidly than the interest we pay on our liabilities, as borrowers prepay mortgage loans, and mortgage-backed securities and callable securities are called, requiring us to reinvest those cash flows at lower interest rates.

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In addition, changes in interest rates can affect the average life of loans and mortgage-backed and related securities. A decline in interest rates generally results in increased prepayments of loans and mortgage-backed and related securities as borrowers refinance their debt to reduce their borrowing costs. This creates reinvestment risk, which is the risk that we may not be able to reinvest prepayments at rates that are comparable to the rates we earned on the prepaid loans or securities. Furthermore, an inverted interest rate yield curve, where short-term interest rates (which are usually the rates at which financial institutions borrow funds) are higher than long-term interest rates (which are usually the rates at which financial institutions lend funds for fixed-rate loans) can reduce a financial institution’s net interest margin and create financial risk for financial institutions that originate longer-term, fixed-rate mortgage loans.

Any substantial, unexpected, prolonged change in market interest rates could have a material adverse effect on our financial condition, liquidity and results of operations. Changes in the level of interest rates also may negatively affect the value of our assets and ultimately affect our earnings.

We monitor interest rate risk through the use of simulation models, including estimates of the amounts by which the fair value of our assets and liabilities (our economic value of equity or “EVE”) and our net interest income would change in the event of a range of assumed changes in market interest rates. As of June 30, 2021, in the event of an instantaneous 100 basis point increase in interest rates, we estimate that we would experience a 4.7% decrease in EVE and a 3.4% increase in net interest income. For further discussion of how changes in interest rates could impact us, see “Management’s Discussion and Analysis of Financial Condition and Results of Operations of Colonial Federal Savings Bank—Management of Market Risk.”

Risks Related to Competitive Matters

Strong competition within our market areas may limit our growth and profitability.

Competition in the banking and financial services industry is intense. In our market area, we compete with commercial banks, savings institutions, mortgage brokerage firms, credit unions, finance companies, mutual funds, insurance companies, and securities brokerage firms and unregulated or less regulated non-banking entities, operating locally and elsewhere. Many of these competitors have substantially greater resources and higher lending limits than we have and offer certain services that we do not or cannot provide. If we must raise interest rates paid on deposits or lower interest rates charged on our loans, our net interest margin and profitability could be adversely affected. In addition, some of our competitors offer loans with lower interest rates on more attractive terms than loans we offer. Competition also makes it increasingly difficult and costly to attract and retain qualified employees. Our profitability depends upon our continued ability to successfully compete in our market area.

The financial services industry could become even more competitive as a result of new legislative, regulatory and technological changes and continued consolidation. Banks, securities firms and insurance companies can merge under the umbrella of a financial holding company, which can offer virtually any type of financial service, including banking, securities underwriting, insurance (both agency and underwriting) and merchant banking. Also, technology has lowered barriers to entry and made it possible for non-banks, such as financial technology companies, securities companies and specialty finance companies to offer products and services traditionally provided by banks, such as automatic transfer and automatic payment systems. Many of our competitors have fewer regulatory constraints and may have lower cost structures. Additionally, due to their size, many competitors may be able to achieve economies of scale and, as a result, may offer a broader range of products and services as well as better pricing for those products and services than we can. We expect competition to increase in the future because of legislative, regulatory and technological changes and the continuing trend of consolidation in the financial services industry. For additional information see “Business of Colonial Federal Savings Bank—Market Area” and “—Competition.”

Our asset size may make it more difficult for us to compete.

Our asset size may make it more difficult to compete with other financial institutions that are larger and can more easily afford to invest in the marketing and technologies needed to attract and retain customers. Because our principal source of income is the net interest income we earn on our loans and investments after deducting interest paid on deposits and other sources of funds, our ability to generate the revenues needed to cover our expenses and finance such investments is limited by the size of our loan and investment portfolios. Accordingly, we are not always able to offer new products and services as quickly as our competitors. Our lower earnings may also make it more difficult to offer competitive salaries and benefits. In addition, our smaller customer base may make it difficult to generate meaningful non-interest income from non-traditional banking activities. Finally, as a smaller institution, we are disproportionately affected by the continually increasing costs of compliance with new banking and other regulations.

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Risks Related to Laws and Regulations

Changes in laws and regulations and the cost of regulatory compliance with new laws and regulations may adversely affect our operations and/or increase our costs of operations.

Colonial Federal Savings Bank is subject to extensive regulation, supervision and examination by the Office of the Comptroller of the Currency, and CFSB Bancorp, Inc. will be subject to extensive regulation, supervision and examination by the Federal Reserve Board. Such regulation and supervision governs the activities in which an institution and its holding company may engage and are intended primarily for the protection of the federal deposit insurance fund and the depositors and borrowers of Colonial Federal Savings Bank, rather than for our stockholders.

Regulatory authorities have extensive discretion in their supervisory and enforcement activities, including the imposition of restrictions on our operations, the classification of our assets and determination of the level of our allowance for loan losses. These regulations, along with existing tax, accounting, securities, insurance and monetary laws, rules, standards, policies, and interpretations, control the methods by which financial institutions conduct business, implement strategic initiatives and tax compliance, and govern financial reporting and disclosures. Any change in such regulation and oversight, whether in the form of regulatory policy, regulations, legislation or supervisory action, may have a material impact on our operations. Further, changes in accounting standards can be both difficult to predict and involve judgment and discretion in their interpretation by us and our independent accounting firm. These changes could materially impact, potentially even retroactively, how we report our financial condition and results of operations.

Non-compliance with the USA PATRIOT Act, Bank Secrecy Act, or other laws and regulations could result in fines or sanctions.

The USA PATRIOT and Bank Secrecy Acts require financial institutions to develop programs to prevent financial institutions from being used for money laundering and terrorist activities. If such activities are detected, financial institutions are obligated to file suspicious activity reports with the U.S. Treasury’s Office of Financial Crimes Enforcement Network. These rules require financial institutions to establish procedures for identifying and verifying the identity of customers seeking to open new financial accounts. Failure to comply with these regulations could result in fines or sanctions, including restrictions on pursuing acquisitions or establishing new branches. The policies and procedures we have adopted that are designed to assist in compliance with these laws and regulations may not be effective in preventing violations of these laws and regulations.

The Federal Reserve Board may require us to commit capital resources to support Colonial Federal Savings Bank, and we may not have sufficient access to such capital resources.

Federal law requires that a holding company act as a source of financial and managerial strength to its subsidiary bank and to commit resources to support such subsidiary bank. Under the “source of strength” doctrine, the Federal Reserve Board may require a holding company to make capital injections into a troubled subsidiary bank and may charge the holding company with engaging in unsafe and unsound practices for failure to commit resources to a subsidiary bank. A capital injection may be required at times when the holding company may not have the resources to provide it and therefore may be required to attempt to borrow the funds or raise capital. Any loans by a holding company to its subsidiary bank are subordinate in right of payment to deposits and to certain other indebtedness of such subsidiary bank. In the event of a holding company’s bankruptcy, the bankruptcy trustee will assume any commitment by the holding company to a federal bank regulatory agency to maintain the capital of a subsidiary bank. Moreover, bankruptcy law provides that claims based on any such commitment will be entitled to a priority of payment over the claims of the institution’s general unsecured creditors, including the holders of its note obligations. Thus, any borrowing that must be done by CFSB Bancorp, Inc.to make a required capital injection becomes more difficult and expensive and could have an adverse effect on our business, financial condition and results of operations. Moreover, it is possible that we will be unable to borrow funds when we need to do so.

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Monetary policies and regulations of the Federal Reserve Board could adversely affect our business, financial condition and results of operations.

In addition to being affected by general economic conditions, our earnings and growth are affected by the policies of the Federal Reserve Board. An important function of the Federal Reserve Board is to regulate the money supply and credit conditions. Among the instruments used by the Federal Reserve Board to implement these objectives are open market purchases and sales of U.S. government securities, adjustments of the discount rate and changes in banks’ reserve requirements against bank deposits. These instruments are used in varying combinations to influence overall economic growth and the distribution of credit, bank loans, investments and deposits. Their use also affects interest rates charged on loans or paid on deposits.

The monetary policies and regulations of the Federal Reserve Board have had a significant effect on the operating results of financial institutions in the past and are expected to continue to do so in the future. The effects of such policies upon our business, financial condition and results of operations cannot be predicted.

We are an emerging growth company, and any decision on our part to comply only with certain reduced reporting and disclosure requirements applicable to emerging growth companies could make our common stock less attractive to investors.

We are an emerging growth company, and, for as long as we continue to be an emerging growth company, we may choose to take advantage of exemptions from various reporting requirements applicable to other public companies but not to “emerging growth companies,” including, but not limited to, reduced disclosure obligations regarding executive compensation in our periodic reports and proxy statements, and exemptions from the requirements of holding a non-binding advisory vote on executive compensation and stockholder approval of any golden parachute payments not previously approved. As an emerging growth company, we also will not be subject to Section 404(b) of the Sarbanes-Oxley Act, which would require that our independent auditors review and attest as to the effectiveness of our internal control over financial reporting. We have also elected to use the extended transition period to delay adoption of new or revised accounting pronouncements applicable to public companies until such pronouncements are made applicable to private companies. Accordingly, our financial statements may not be comparable to the financial statements of public companies that comply with such new or revised accounting standards.

We can remain an “emerging growth company” for up to five years, or until the earliest of (1) the last day of the first fiscal year in which our annual gross revenues exceed $1.07 billion, (2) the date that we become a “large accelerated filer” as defined in Rule 12b-2 under the Securities Exchange Act of 1934, which would occur if the market value of our common stock that is held by non-affiliates exceeds $700 million as of the last business day of our most recently completed second fiscal quarter, or (3) the date on which we have issued more than $1.0 billion in non-convertible debt during the preceding three-year period.

As a result, our stockholders may not have access to certain information they may deem important, and investors may find our common stock less attractive if we choose to rely on these exemptions. This could result in a less active trading market for our common stock and the price of our common stock may be more volatile.

We qualify as a smaller reporting company, and any decision on our part to comply only with certain reduced reporting and disclosure requirements applicable to smaller reporting companies could make our common stock less attractive to investors.

We are a smaller reporting company, and, for as long as we continue to qualify as a smaller reporting company, we may choose to take advantage of exemptions from various reporting requirements applicable to other public companies but not to smaller reporting companies, including, but not limited to, reduced disclosure obligations regarding executive compensation in our periodic reports and proxy statements and two years of audited financial statements in our annual report instead of three years. As long as we are not an accelerated filer, we will not be subject to Section 404(b) of the Sarbanes-Oxley Act, which requires that our independent registered public accountants review and attest as to the effectiveness of our internal control over financial reporting. In addition, as a non-accelerated filer, we will have longer deadlines to file our periodic reports with the Securities and Exchange Commission.

We would remain a smaller reporting company and a non-accelerated filer for so long as our voting and non-voting equity held by non-affiliates (“public float”) is less than $250 million or our annual revenues are less than $100 million and our public float is less than $700 million. Public float is determined each year as of the end of a company’s second fiscal quarter applicable at the end of the fiscal year involved.

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As a result of our smaller reporting company and non-accelerated filer status, our stockholders may not have access to certain information they may deem important, and investors may find our common stock less attractive if we choose to rely on these exemptions. This could result in a less active trading market for our common stock and the price of our common stock may be more volatile.

Risks Related to Operational Matters

We face significant operational risks because of our reliance on technology. Our information technology systems may be subject to failure, interruption or security breaches.

Information technology systems are critical to our business. Our business requires us to collect, process, transmit and store significant amounts of confidential information regarding our customers, employees and our own business, operations, plans and business strategies. We use various technology systems to manage our customer relationships, general ledger, securities investments, deposits, and loans. Our computer systems, data management and internal processes, as well as those of third parties, are integral to our performance. Our operational risks include the risk of malfeasance by employees or persons outside our company, errors relating to transaction processing and technology, systems failures or interruptions, breaches of our internal control systems and compliance requirements, and business continuation and disaster recovery. There have been increasing efforts by third parties to breach data security at financial institutions. Such attacks include computer viruses, malicious or destructive code, phishing attacks, denial of service or information or other security breaches that could result in the unauthorized release, gathering, monitoring, misuse, loss or destruction of confidential, proprietary and other information, damages to systems, or other material disruptions to network access or business operations. Although we take protective measures and believe that we have not experienced any of the data breaches described above, the security of our computer systems, software, and networks may be vulnerable to breaches, unauthorized access, misuse, computer viruses, or other malicious code and cyber-attacks that could have an impact on information security. Because the techniques used to cause security breaches change frequently, we may be unable to proactively address these techniques or to implement adequate preventative measures.

In the event of a breakdown in our internal control systems, improper operation of systems or improper employee actions, or a breach of our security systems, including if confidential or proprietary information were to be mishandled, misused or lost, we could suffer financial loss, loss of customers and damage to our reputation, and face regulatory action or civil litigation. Any of these events could have a material adverse effect on our financial condition and results of operations. Insurance coverage may not be available for such losses, or where available, such losses may exceed insurance limits.

We rely on third-party vendors, which could expose us to additional cybersecurity risks.

Third-party vendors provide key components of our business infrastructure, including certain data processing and information services. Accordingly, our operations are exposed to risk that these vendors will not perform in accordance with our contractual agreements with them, or we also could be adversely affected if such an agreement is not renewed by the third-party vendor or is renewed on terms less favorable to us. If our third-party providers encounter difficulties, or if we have difficulty communicating with those service providers, our ability to adequately process and account for transactions could be affected, and our business operations could be adversely affected, which could have a material adverse effect on our financial condition and results of operations. Threats to information security also exist in the processing of customer information through various other vendors and their personnel.

We may be subject to risks and losses resulting from fraudulent activities that could adversely impact our financial performance and results of operations.

As a bank, we are susceptible to fraudulent activity that may be committed against us or our clients, which may result in financial losses or increased costs to us or our clients, disclosure or misuse of our information or our client information, misappropriation of assets, privacy breaches against our clients, litigation or damage to our reputation. We are most susceptible to fraud and compliance risk in connection with the origination of loans, automated clearing house transactions, wire transactions, automated teller machine transactions, checking transactions, and debit cards that we have issued to our customers and through our online banking portals.

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We maintain a system of internal controls and insurance coverage to mitigate against such risks, including data processing system failures and errors, and customer fraud. If our internal controls fail to prevent or detect any such occurrence, or if any resulting loss is not insured or exceeds applicable insurance limits, it could have a material adverse effect on our business, financial condition and results of operations.

The cost of additional finance and accounting systems, procedures and controls in order to satisfy our new public company reporting requirements will increase our expenses.

As a result of the completion of this offering, we will become a public reporting company. The obligations of being a public company, including the substantial public reporting obligations, will require significant expenditures and place additional demands on our management team. We have made, and will continue to make, changes to our internal controls and procedures for financial reporting and accounting systems to meet our reporting obligations as a public company. However, the measures we take may not be sufficient to satisfy our obligations as a public company. Section 404 of the Sarbanes-Oxley Act of 2002 requires annual management assessments of the effectiveness of our internal control over financial reporting, starting with the second annual report that we would expect to file with the Securities and Exchange Commission. Any failure to achieve and maintain an effective internal control environment could have a material adverse effect on our business and stock price. In addition, we may need to hire additional compliance, accounting and financial staff with appropriate public company experience and technical knowledge, and we may not be able to do so in a timely fashion. As a result, we may need to rely on outside consultants to provide these services for us until qualified personnel are hired. These obligations will increase our operating expenses and could divert our management’s attention from our operations.

Risks Related to Accounting Matters

Changes in accounting standards could affect reported earnings.

The bodies responsible for establishing accounting standards, including the Financial Accounting Standards Board, the Securities and Exchange Commission and other regulatory bodies, periodically change the financial accounting and reporting guidance that govern the preparation of our financial statements. These changes can be hard to predict and can materially impact how we record and report our financial condition and results of operations. In some cases, we could be required to apply new or revised guidance retroactively.

If management’s estimates and assumptions are incorrect, it may have a material impact on our consolidated financial statements and our financial condition or operating results.

In preparing this prospectus as well as periodic reports we will be required to file under the Securities Exchange Act of 1934, including our consolidated financial statements, our management is and will be required under applicable rules and regulations to make estimates and assumptions as of a specified date. These estimates and assumptions are based on management’s best estimates and experience as of that date and are subject to substantial risk and uncertainty. Materially different results may occur as circumstances change and additional information becomes known. The most significant areas requiring significant estimates and assumptions by management include our evaluation of the adequacy of our allowance for loan losses.

Other Risks Related to Our Business

Legal and regulatory proceedings and related matters could adversely affect us.

We have been and may in the future become involved in legal and regulatory proceedings. We consider most of the proceedings to be in the normal course of our business or typical for the industry; however, it is inherently difficult to assess the outcome of these matters, and we may not prevail in any proceedings or litigation. There could be substantial costs and management diversion in such litigation and proceedings, and any adverse determination could have a materially adverse effect on our business, brand or image, or our financial condition and results of our operations.

Societal responses to climate change could adversely affect our business and performance, including indirectly through impacts on our customers.

Concerns over the long-term effects of climate change have led and will continue to lead to governmental efforts around the world to mitigate those impacts. Consumers and businesses also may voluntarily change their

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behavior as a result of these concerns. We and our customers will need to respond to new laws and regulations as well as consumer and business preferences resulting from climate change concerns. We and our customers may face cost increases, asset value reductions and operating process changes. The impact on our customers will likely vary depending on their specific attributes, including reliance on or role in carbon intensive activities. Among the impacts to us could be a drop in demand for our products and services, particularly in certain sectors. In addition, we could face reductions in creditworthiness on the part of some customers or in the value of assets securing loans. Our efforts to take these risks into account in making lending and other decisions, including by increasing our business with climate-friendly companies, may not be effective in protecting us from the negative impact of new laws and regulations or changes in consumer or business behavior.

We are a community bank and our ability to maintain our reputation is critical to the success of our business, and the failure to do so may materially adversely affect our performance.

We are a community bank, and our reputation is one of the most valuable components of our business. A key component of our business strategy is to rely on our reputation for customer service and knowledge of local markets to expand our presence by capturing new business opportunities from existing and prospective customers in our market area and contiguous areas. As such, we strive to conduct our business in a manner that enhances our reputation. This is done, in part, by recruiting, hiring and retaining employees or by retaining, appointing or electing directors who share our core values of being an integral part of the communities we serve, delivering superior service to our customers and caring about our customers and employees. If our reputation is negatively affected by the actions of our employees or directors, by our inability to conduct our operations in a manner that is appealing to current or prospective customers, or otherwise, our business and, therefore, our operating results may be materially adversely affected.

Risks Related to the Offering

The future price of our common stock may be less than the purchase price in the stock offering.

If you purchase shares of common stock in the stock offering, you may not be able to sell them at or above the purchase price in the stock offering. The purchase price in the offering is based upon an independent third-party appraisal of the pro forma market value of CFSB Bancorp, Inc., pursuant to federal banking regulations and subject to review and approval by the Federal Reserve Board. The appraisal is not intended, and should not be construed, as a recommendation of any kind as to the advisability of purchasing shares of our common stock. Our aggregate pro forma market value as reflected in the final independent appraisal may exceed the market price of our shares of common stock after the completion of the offering, which may result in our stock trading below the initial offering price of $10.00 per share.

After the shares of our common stock begin trading, the trading price of the common stock will be determined by the marketplace, and will be influenced by many factors outside of our control, including prevailing interest rates, investor perceptions, securities analyst research reports and general industry, geopolitical and economic conditions. Publicly traded stocks, including stocks of financial institutions, often experience substantial market price volatility. These market fluctuations may not be related to the operating performance of particular companies whose shares are traded.

Persons who purchase stock in the offering will own a minority of CFSB Bancorp, Inc.’s common stock and will not be able to exercise voting control over most matters put to a vote of stockholders.

Public stockholders will own a minority of the outstanding shares of CFSB Bancorp, Inc.’s common stock. As a result, stockholders other than 15 Beach, MHC will not be able to exercise voting control over most matters put to a vote of stockholders. 15 Beach, MHC will own a majority of CFSB Bancorp, Inc.’s common stock after the reorganization and offering and, through its board of directors, will be able to exercise voting control over most matters put to a vote of stockholders. The same directors and officers who manage Colonial Federal Savings Bank will also manage CFSB Bancorp, Inc. and 15 Beach, MHC. The board of directors and officers of 15 Beach, MHC must ensure that the interests of depositors of Colonial Federal Savings Bank (as members of 15 Beach, MHC) are represented and considered in matters put to a vote of stockholders of CFSB Bancorp, Inc. Therefore, 15 Beach, MHC may take action that the public stockholders believe to be contrary to their interests. For example, 15 Beach, MHC may exercise its voting control to defeat a stockholder nominee for election to the board of directors of CFSB Bancorp, Inc.

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In addition, stockholders will not be able to force a merger or second-step conversion transaction without the consent of 15 Beach, MHC since such transactions also require the approval of a majority of all of the outstanding voting stock of CFSB Bancorp, Inc., which can only be achieved if 15 Beach, MHC votes to approve such transactions. Some stockholders may desire a sale or merger transaction, since stockholders typically receive a premium for their shares, or a second-step conversion transaction, since, on a fully converted basis, most full stock institutions tend to trade at higher multiples than mutual holding companies. Stockholders could, however, prevent a second-step conversion or the implementation of equity incentive plans because under current regulations and policies, such matters also require the separate approval of the stockholders other than 15 Beach, MHC.

We have broad discretion in using the proceeds of the stock offering. Our failure to effectively deploy the net proceeds of the offering may have an adverse effect on our financial performance and the value of our common stock.

We intend to invest between $8.4 million and $11.6 million of the net proceeds of the offering (or $13.5 million at the adjusted maximum of the offering range) in Colonial Federal Savings Bank. We also expect to use a portion of the net proceeds we retain to fund a loan for the purchase of shares of common stock in the offering by our employee stock ownership plan. We may use the remaining net proceeds to invest in short-term and other investments and for other general corporate purposes, including the repurchase of shares of our common stock. Colonial Federal Savings Bank intends to use the net proceeds it receives to fund new loans, enhance existing products and services, invest in securities, expand its banking franchise by acquiring other financial institutions as opportunities arise, or for other general corporate purposes. However, with the exception of the loan to the employee stock ownership plan and the contribution to the charitable foundation, we have not allocated specific amounts of the net proceeds for any of these purposes, and we will have significant flexibility in determining the amount of the net proceeds we apply to different uses and the timing of such applications. Also, certain of these uses, such as acquiring other financial institutions may require the approval of the Office of the Comptroller of the Currency or the Federal Reserve Board. We have not established a timetable for investing the net proceeds, and, accordingly, we may not invest the net proceeds at a time that is most beneficial to CFSB Bancorp, Colonial Federal Savings Bank or our stockholders.

There will be a limited trading market in our common stock, which would hinder your ability to sell our common stock and may lower the market price of the stock.

We have never issued capital stock and there is no established market for our common stock. We expect that our common stock will be traded on the Nasdaq Capital Market, subject to completion of the offering and compliance with certain conditions. Piper Sandler has advised us that it intends to make a market in our common stock following the offering, but it is under no obligation to do so or to continue to do so once trading begins. The development of an active trading market depends on the existence of willing buyers and sellers, the presence of which is not within our control, or that of any market maker. The number of active buyers and sellers of the shares of common stock at any particular time may be limited. Under such circumstances, you could have difficulty selling your shares of common stock on short notice, and, therefore, you should not view the shares of common stock as a short-term investment. In addition, our public “float,” which is the number of our outstanding shares less the shares held by our employee stock ownership plan and our directors and executive officers, will be quite limited. As a result, it is unlikely that an active trading market for the common stock will develop or that, if it develops, it will continue. If you purchase shares of common stock, you may not be able to sell them at or above $10.00 per share. Purchasers of common stock in this stock offering should have long-term investment intent and should recognize that there will be a limited trading market in the common stock. This may make it difficult to sell the common stock after the stock offering and may have an adverse impact on the price at which the common stock can be sold.

The capital we raise in the stock offering may negatively impact our return on equity until we can fully implement our business plan. This could negatively affect the trading price of our shares of common stock.

Net income divided by average equity, known as “return on equity,” is a ratio many investors use to compare the performance of a financial institution to its peers. We expect our return on equity to remain relatively low until we are able to implement our business plan and leverage the additional capital we receive from the offering. Although we anticipate increasing net interest income using proceeds of the offering, our return on equity will be reduced by the capital raised in the offering, higher expenses from the costs of being a public company, and added expenses associated with our employee stock ownership plan and the stock-based benefit plan we intend to adopt. Until we can implement our business plan and increase our net interest income through investment of the proceeds of the offering, we expect our return on equity to remain relatively low compared to our peer group, which may reduce the value of our shares.

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Federal Reserve Board regulations and policy effectively prohibit 15 Beach, MHC from waiving the receipt of dividends, which will likely preclude us from paying any dividends on our common stock.

CFSB Bancorp, Inc.’s board of directors will have the authority to declare dividends on our common stock subject to statutory and regulatory requirements. We currently intend to retain all our future earnings, if any, for use in our business and do not expect to pay any cash dividends on our common stock in the foreseeable future. Any future determination to pay cash dividends will be made by our board of directors and will depend upon our financial condition, results of operations, capital requirements, restrictions under Federal Reserve Board regulations and policy, our business strategy and other factors that our board of directors deems relevant.

Under Federal Reserve Board regulations and policy, if CFSB Bancorp, Inc. pays dividends to its public stockholders, it also would be required to pay dividends to 15 Beach, MHC, unless 15 Beach, MHC waives the receipt of such dividends. Federal Reserve Board regulations implemented after the enactment of the Dodd–Frank Wall Street Reform and Consumer Protection Act (the “Dodd-Frank Act”) effectively prohibit federally-chartered mutual holding companies from waiving dividends declared by their subsidiaries. See “Supervision and Regulation—Holding Company Regulation—Waivers of Dividends by 15 Beach, MHC” for a further discussion of the applicable requirements related to the potential waiver of dividends by a mutual holding company. Moreover, since CFSB Bancorp, Inc. will sell only a minority of its shares to the public and will contribute the remaining shares to 15 Beach, MHC, CFSB Bancorp, Inc. will raise significantly less capital than would have been the case if it sold all its shares to the public. As a result, paying dividends to 15 Beach, MHC, which is an entity that will not be paying for the shares of CFSB Bancorp, Inc. common stock it receives in connection with the offering, may be inequitable to public stockholders and not in their best financial interests. Therefore, unless Federal Reserve Board regulations and policy change by allowing 15 Beach, MHC to waive the receipt of dividends declared by CFSB Bancorp, Inc. without diluting minority stockholders, it is unlikely that CFSB Bancorp, Inc. will pay any dividends.

Our stock-based benefit plan will increase our expenses, which will reduce our net income.

We intend to implement a stock-based benefit plan after the offering, subject to stockholder approval, which would increase our annual compensation and benefit expenses related to stock options and stock awards granted to participants under the stock-based benefit plan. The amount of these stock-related compensation and benefit expenses would depend on the number of options and stock awards granted, the fair value of the options and our stock on the date of grant, the vesting period, and other factors that we cannot predict at this time. If we implement stock-based benefit plan within 12 months following the completion of the reorganization and offering, the total shares of common stock reserved for issuance pursuant to awards of restricted stock and grants of options under such plan would be limited to 1.96% and 4.90%, respectively, of the outstanding shares of common stock of CFSB Bancorp, Inc. at the completion of the reorganization and offering (including shares issued to 15 Beach, MHC and shares contributed to the foundation). If we award restricted shares of common stock or grant options in excess of these amounts under a stock-based benefit plan implemented more than 12 months after the completion of the offering, our expenses would increase further.

We anticipate that our employee stock ownership plan will purchase 3.92% of our outstanding shares (including shares issued to 15 Beach, MHC and shares contributed to the foundation). The cost of acquiring the shares of common stock for the employee stock ownership plan is estimated to be between $1.7 million at the minimum of the offering range and $2.6 million at the adjusted maximum of the offering range (assuming we are able to purchase all of such shares in the offering). We will record annual employee stock ownership plan expenses in an amount equal to the fair value of shares of common stock committed to be released to employees. If shares of common stock appreciate in value over time, compensation expense relating to the employee stock ownership plan will increase.

The estimated expense in the first year following the offering for shares purchased in the offering (or in the after-market if the offering is oversubscribed by the eligible account holders) by our employee stock ownership plan and for a stock-based benefit plan implemented within one year after the offering, subject to receipt of stockholder approval, is approximately $587,000 ($482,000 after tax) at the adjusted maximum of the offering range as set forth in the pro forma financial information under “Pro Forma Data,” assuming the $10.00 per share offering price as fair market value. Actual expense may be higher if the price of our common stock at the time the shares are allocated or awarded is greater than $10.00 per share. For further discussion of our proposed stock-based plans, see “Management—Benefits to be Considered Following Completion of the Stock Offering.”

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The implementation of a stock-based benefit plan is likely to dilute your ownership interest.

We intend to adopt a stock-based benefit plan, which will allow participants to be awarded shares of common stock (at no cost to them) and/or options to purchase shares of our common stock, following the offering. If this stock-based benefit plan is funded solely from the issuance of authorized but unissued shares of common stock, stockholders would experience a reduction in ownership interest totaling 6.42%. Although the implementation of a stock-based benefit plan will be subject to stockholder approval, historically, the overwhelming majority of stock-based benefit plans adopted by savings institutions and their holding companies following mutual-to-stock conversions or mutual holding company reorganizations have been approved by stockholders.

We have not determined the timing of the adoption of stock-based benefit plan following the stock offering. Stock-based benefit plans adopted more than one year following the completion of the reorganization and offering may exceed regulatory restrictions on the size of stock-based benefit plans adopted within one year, which would increase our expenses and the dilution to other stockholders.

If we adopt a stock-based benefit plan within one year following the completion of the reorganization and offering, then we may grant shares of common stock or stock options under our stock-based benefit plan for up to 4.90% and 1.96%, respectively, of the outstanding shares of common stock of CFSB Bancorp, Inc. at the completion of the offering (including shares issued to 15 Beach, MHC and contributed to the charitable foundation). The amount of stock awards and stock options available for grant under the stock-based benefit plan may exceed these amounts, provided the stock-based benefit plan is adopted more than one year following the offering. Although the implementation of stock-based benefit plan will be subject to stockholder approval, the determination as to the timing of the implementation of such plan will be at the discretion of our board of directors. A stock-based benefit plan that provides for awards in excess of these amounts would increase our expenses beyond the amounts estimated in “—Our stock-based benefit plans will increase our expenses, which will reduce our net income.” A stock-based benefit plan that provides for awards in excess of these amounts could also result in dilution to stockholders in excess of that described in “—The implementation of a stock-based benefit plan is likely to dilute your ownership interest.”

Various factors may make takeover attempts more difficult to achieve.

Stock banks or their holding companies, as well as individuals, may not acquire control of a mutual holding company, such as CFSB Bancorp. As a result, the only persons that may acquire control of a mutual holding company are other mutual savings institutions or mutual holding companies. Accordingly, it is very unlikely that CFSB Bancorp, Inc. would be subject to any takeover attempt by activist stockholders or other financial institutions. There also are provisions in our charter and bylaws that may be used to delay or block a takeover attempt, including a provision that prohibits any person, other than 15 Beach, MHC, from voting more than 10% of the shares of common stock outstanding. In addition, federal banking laws, including regulatory approval requirements, could make it more difficult for a third party to acquire control of CFSB Bancorp, Inc. without our board of directors’ prior approval.

Under Federal Reserve Board regulations, for a period of three years following completion of the offering, no person may directly or indirectly acquire or offer to acquire beneficial ownership of more than 10% of our common stock without prior approval of the Federal Reserve Board. In addition, under federal law, subject to certain exemptions, a person, entity or group must notify the Federal Reserve Board before acquiring control of a savings and loan holding company. Acquisition of 10% or more of any class of voting stock of a savings and loan holding company creates a rebuttable presumption that the acquirer “controls” the savings and loan holding company. Also, a savings and loan holding company must obtain the prior approval of the Federal Reserve Board before, among other things, acquiring direct or indirect ownership or control of more than 5% of any class of voting shares of any financial institution holding company or bank, including Colonial Federal Savings Bank.

In addition, a section in CFSB Bancorp, Inc.’s charter provides that for a period of five years from the closing of the offering, no person, other than 15 Beach, MHC, may directly or indirectly offer to acquire or acquire the beneficial ownership of more than 10% of any class of equity security of CFSB Bancorp, Inc. held by persons other than 15 Beach, MHC, and that any shares acquired in excess of this limit will not be entitled to be voted and will not be counted as voting stock in connection with any matters submitted to the stockholders for a vote.

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Taken as a whole, these statutory provisions and provisions in our articles of incorporation and bylaws make it very difficult for any potential acquiror from acquiring control of CFSB Bancorp, Inc. without the approval of our board of directors, which could adversely affect the market price of our common stock.

For additional information, see “Restrictions on the Acquisition of CFSB Bancorp, Inc. and Colonial Federal Savings Bank” “Management—Agreements and Benefit Plans” and “—Benefits to be Considered Following Completion of the Stock Offering.”

You may not revoke your decision to purchase CFSB Bancorp, Inc. common stock in the subscription or community offerings after you send us your order.

Funds submitted or automatic withdrawals authorized in connection with the purchase of shares of common stock in the subscription and community offerings will be held by us until the completion or termination of the reorganization and offering, including any extension of the expiration date and consummation of a syndicated offering. Because completion of the reorganization and offering will be subject to regulatory approvals and an update of the independent appraisal prepared by RP Financial, LC., among other factors, there may be one or more delays in completing the reorganization and offering. Orders submitted in the subscription and community offerings are irrevocable, and purchasers will have no access to their funds unless the offering is terminated, or extended beyond [EXT DATE 1], or the number of shares to be sold in the offering is increased to more than 2,843,375 shares or decreased to fewer than 1,827,500 shares.

The distribution of subscription rights could have adverse income tax consequences.

If the subscription rights granted to certain current or former depositors of Colonial Federal Savings Bank are deemed to have an ascertainable value, receipt of such rights may be taxable in an amount equal to such value. Whether subscription rights are considered to have ascertainable value is an inherently factual determination. We have received an opinion of counsel, Luse Gorman, PC, that it is more likely than not that such rights have no value; however, such opinion is not binding on the Internal Revenue Service.

Risks Related to the Charitable Foundation

The contribution to the charitable foundation will dilute your ownership interest and adversely affect net income in 2022.

We intend to establish and fund a new charitable foundation in connection with the reorganization and offering. We intend to contribute $250,000 in cash and 2.0% of our outstanding shares, or 100,000 shares at the midpoint of the offering range (for an aggregate contribution of $1,250,000, at the midpoint of the offering range, based on the $10.00 per share offering price) to this charitable foundation. The contribution will have an adverse effect on our net income for the quarter and year in which we make the issuance and contribution to the charitable foundation. The after-tax expense of the contribution is expected to reduce net income in the year of the contribution by approximately $937,000, at the midpoint of the offering range. Our 2021 net income was $1.4 million.

Our contribution to the charitable foundation may not be tax deductible, which could reduce our profits.

We may not have sufficient profits to be able to fully use the tax deduction from our contribution to the charitable foundation. Under the Internal Revenue Code, an entity is permitted to deduct up to 10% of its taxable income (generally income before federal income taxes and charitable contributions expense) in any one year for charitable contributions. Any contribution in excess of the 10% limit may be deducted for federal income tax purposes over each of the five years following the year in which the charitable contribution is made. Accordingly, a charitable contribution could, if necessary, be deducted over a six-year period and expires thereafter.

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SELECTED FINANCIAL AND OTHER DATA

The following tables set forth selected historical financial and other data for Colonial Federal Savings Bank at the dates and for the periods indicated. It is only a summary and it should be read in conjunction with the business and financial information contained elsewhere in this prospectus, including the consolidated financial statements beginning on page F-1. The information at June 30, 2021 and 2020 and for the years ended June 30, 2021 and 2020 is derived in part from the audited financial statements appearing elsewhere in this prospectus.

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CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS

This prospectus contains forward-looking statements, which can be identified by the use of words such as “estimate,” “project,” “believe,” “intend,” “anticipate,” “assume,” “plan,” “seek,” “expect,” “will,” “may,” “should,” “indicate,” “would,” “contemplate,” “continue,” “target” and words of similar meaning. These forward-looking statements include, but are not limited to:

These forward-looking statements are based on our current beliefs and expectations and are inherently subject to significant business, economic and competitive uncertainties and contingencies, many of which are beyond our control. In addition, these forward-looking statements are subject to assumptions with respect to future business strategies and decisions that are subject to change. We are under no duty to and do not take any obligation to update any forward-looking statements after the date of this prospectus.

The following factors, among others, could cause actual results to differ materially from the anticipated results or other expectations expressed in the forward-looking statements:

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Because of these and a wide variety of other uncertainties, our actual future results may be materially different from the results indicated by these forward-looking statements. Please see “Risk Factors” beginning on page 18.

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HOW WE INTEND TO USE THE PROCEEDS FROM THE OFFERING

Although we will not be able to determine the amount of actual net proceeds we will receive from the sale of shares of common stock until the offering is completed, we anticipate that the net proceeds will be between $16.9 million and $23.2 million, or $26.9 million if the offering is increased by 15%.

CFSB Bancorp, Inc. intends to distribute the net proceeds from the offering as follows:

The net proceeds may vary because total expenses relating to the reorganization and offering may be more or less than our estimates. For example, our expenses would increase if a syndicated community offering were used to sell shares of common stock not purchased in the subscription offering and the community offering. See “The Reorganization and Offering—Plan of Distribution and Marketing Arrangements” for a discussion of fees to be paid in the event that shares are sold in a syndicated community offering. Payments for shares made through withdrawals from existing deposit accounts will not result in the receipt of new funds for investment but will result in a reduction of Colonial Federal Savings Bank’s deposits. Colonial Federal Savings Bank will receive at least 50% of the net proceeds of the offering.

Use of Proceeds Retained by CFSB Bancorp, Inc.

CFSB Bancorp, Inc.:

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Use of Proceeds Received by Colonial Federal Savings Bank

Colonial Federal Savings Bank:

The use of the proceeds by CFSB Bancorp, Inc. and Colonial Federal Savings Bank may change based on changes in interest rates, equity markets, laws and regulations affecting the financial services industry, our relative position in the financial services industry, the attractiveness of potential acquisitions to expand our operations, and overall market conditions.

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OUR POLICY REGARDING DIVIDENDS

We do not currently intend to pay dividends on our common stock following completion of the offering. In the event that we do determine to pay dividends in the future, the payment and amount of any dividends will depend upon a number of factors, including the following: regulatory capital requirements; our financial condition and results of operations; our other uses of funds for the long-term value of stockholders; tax considerations; the Federal Reserve Board’s current regulations restricting the waiver of dividends by mutual holding companies; statutory and regulatory limitations; and general economic conditions.

The Federal Reserve Board has issued a policy statement providing that dividends should be paid only out of current earnings and only if our prospective rate of earnings retention is consistent with our capital needs, asset quality and overall financial condition. Regulatory guidance also provides for prior regulatory consultation with respect to capital distributions in certain circumstances such as where the holding company’s net income for the past four quarters, net of dividends previously paid over that period, is insufficient to fully fund the dividend or the holding company’s overall rate or earnings retention is inconsistent with its capital needs and overall financial condition.

CFSB Bancorp, Inc. will file a consolidated federal tax return with Colonial Federal Savings Bank. Accordingly, it is anticipated that any cash distributions that CFSB Bancorp, Inc. makes to its stockholders would be treated as cash dividends and not as a non-taxable return of capital for federal and state tax purposes. Additionally, pursuant to regulations of the Federal Reserve Board, during the three-year period following the completion of the reorganization and offering, CFSB Bancorp, Inc. will not take any action to declare an extraordinary dividend to its stockholders that would be treated by recipients as a tax-free return of capital for federal income tax purposes.

Pursuant to our charter, we are authorized to issue preferred stock. If we issue preferred stock, the holders thereof may have a priority over the holders of our shares of common stock with respect to the payment of dividends. For a further discussion concerning the payment of dividends on our shares of common stock, see “Description of Capital Stock of CFSB Bancorp, Inc.—Common Stock.” Dividends we can declare and pay will depend, in part, upon receipt of dividends from Colonial Federal Savings Bank, because initially we will have no source of income other than dividends from Colonial Federal Savings Bank and earnings from the investment of the net proceeds from the sale of shares of common stock retained by CFSB Bancorp, Inc. and interest payments received in connection with the loan to the employee stock ownership plan. Regulations of the Federal Reserve Board and the Office of the Comptroller of the Currency impose limitations on “capital distributions” by savings institutions. See “Regulation and Supervision—Federal Banking Regulation—Capital Distributions.”

Any payment of dividends by Colonial Federal Savings Bank to CFSB Bancorp, Inc. that would be deemed to be drawn out of Colonial Federal Savings Bank’s bad debt reserves, if any, would require a payment of taxes at the then-current tax rate by Colonial Federal Savings Bank on the amount of earnings deemed to be removed from the reserves for such distribution. Colonial Federal Savings Bank does not intend to make any distribution to CFSB Bancorp, Inc. that would create such a federal tax liability. See “Taxation.”

If CFSB Bancorp, Inc. pays dividends to its stockholders, it will likely pay dividends to 15 Beach, MHC. The Federal Reserve Board’s current regulations significantly restrict the ability of mutual holding companies organized after December 1, 2009 to waive dividends declared by their subsidiaries. Accordingly, we do not currently anticipate that 15 Beach, MHC will waive dividends paid by CFSB Bancorp, Inc. See “Risk Factors—Risks Related to the Offering—Under current law, if we declare dividends on our common stock, 15 Beach, MHC will be restricted from waiving the receipt of dividends” and “Supervision and Regulation—Federal Banking Regulation—Waivers of Dividends by 15 Beach, MHC.”

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MARKET FOR THE COMMON STOCK

CFSB Bancorp, Inc. is a to-be-formed company and has never issued capital stock. Colonial Federal Savings Bank, as a mutual institution, has never issued capital stock. Accordingly, there is no established market for our common stock. CFSB Bancorp, Inc. expects that its common stock will be quoted on the Nasdaq Capital Market under the symbol “[ticker]” upon completion of the offering, including the presence of at least three registered and active market makers. Pier Sandler has advised us that it intends to make a market in shares of our common stock following the offering, but it is not obligated to do so or to continue to do so once it begins. While we will attempt before completion of the offering to obtain commitments from at least two other broker-dealers to make a market in shares of our common stock, there can be no assurance that we will be successful in obtaining such commitments.

The development of an active trading market depends on the existence of willing buyers and sellers, the presence of which is not within our control, or that of any market maker. The number of active buyers and sellers of the shares of common stock at any particular time may be limited. Under such circumstances, you could have difficulty selling your shares of common stock on short notice, and, therefore, you should not view the shares of common stock as a short-term investment. Furthermore, we cannot assure you that, if you purchase shares of common stock, you will be able to sell them at or above $10.00 per share. Purchasers of common stock in this offering should have long-term investment intent and should recognize that there may be a limited trading market in the common stock. This may make it difficult to sell the common stock after the offering and may have an adverse impact on the price at which the common stock can be sold.

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HISTORICAL AND PRO FORMA REGULATORY CAPITAL COMPLIANCE

At June 30, 2021, Colonial Federal Savings Bank exceeded all applicable regulatory capital requirements and was considered “well capitalized.” The table below sets forth, at June 30, 2021, the historical equity capital and regulatory capital and the pro forma equity capital and regulatory capital of Colonial Federal Savings Bank after giving effect to the sale of shares of common stock at $10.00 per share. The tabular data assumes the receipt by Colonial Federal Savings Bank of 50% of the net offering proceeds. See “How We Intend to Use the Proceeds from the Offering.”