WHAT ARE THE CONVERSION AND STOCK OFFERING?

Under our plan of conversion, Blue Foundry, MHC will convert from the mutual holding company to the stock holding company form of organization. Concurrently with the conversion, Blue Foundry Bancorp, a newly formed holding company, will offer shares of its common stock for sale to our depositors and members of the public. Upon completion of the conversion, Blue Foundry, MHC and Blue Foundry Bancorp-NJ will cease to exist, and Blue Foundry Bank will be a wholly owned subsidiary of Blue Foundry Bancorp.

WHAT ARE THE REASONS FOR THE CONVERSION AND STOCK OFFERING?

Our primary reasons for the conversion and the stock offering are to: raise capital to support internal growth through lending and deposit gathering in the communities we serve; enhance existing products and services, and support the development of new products and services to support growth and enhance customer service; attract and retain qualified directors, management and employees through equity ownership and stock-based compensation plans; raise capital to make necessary capital investments in facilities and technology to support our internal growth; increase philanthropic endeavors to the communities served by Blue Foundry Bank through the formation and funding of a charitable foundation; facilitate future mergers and acquisitions; and use the additional capital for other general corporate purposes.

IS BLUE FOUNDRY BANK CONSIDERED “WELL-CAPITALIZED” FOR REGULATORY PURPOSES?

Yes. As of December 31, 2020, Blue Foundry Bank was considered “well-capitalized” for regulatory purposes.

WILL CUSTOMERS NOTICE ANY CHANGE IN BLUE FOUNDRY BANK’S DAY-TO-DAY ACTIVITIES AS A RESULT OF THE CONVERSION AND STOCK OFFERING?

No. It will be business as usual. The conversion is an internal change to our corporate structure. There will be no change to our board of directors, management and staff as a result of the conversion and stock offering. Blue Foundry Bank will continue to operate as an independent bank.

WILL THE CONVERSION AND STOCK OFFERING AFFECT CUSTOMERS’ DEPOSIT ACCOUNTS OR LOANS?

No. The conversion and stock offering will not affect the balance or terms of deposits or loans, and deposits will continue to be federally insured by the Federal Deposit Insurance Corporation up to the maximum legal limits. Deposit accounts will not be converted to stock.

WHAT IS THE BLUE FOUNDRY FOUNDATION AND WHY IS IT BEING FUNDED THROUGH THE CONVERSION?

We intend to contribute to our charitable foundation a total of 750,000 shares of our common stock and $1.5 million in cash. The purpose of our charitable foundation is to provide financial support to charitable organizations in the communities in which we operate and will operate in the future and to enable our communities to share in our long-term growth. Our charitable foundation will be dedicated to community activities and the promotion of charitable causes, and may be able to support such activities in ways that are not presently available to us.

WILL THE CHARITABLE FOUNDATION BE ESTABLISHED AND FUNDED IF THE CONVERSION AND OFFERING ARE NOT APPROVED AND COMPLETED?

No. The charitable foundation will only be established and funded if both the plan of conversion and the charitable foundation are approved by our eligible depositors. However, if we receive all other approvals, we will be permitted to complete the conversion without the charitable foundation if the establishment and funding of the charitable foundation is not approved by our depositors.

WHY SHOULD I VOTE “FOR” THE PLAN OF CONVERSION AND “FOR” THE ESTABLISHMENT AND FUNDING OF THE CHARITABLE FOUNDATION?

Your vote “FOR” both proposals is extremely important to us. Each eligible Blue Foundry Bank depositor as of May 5, 2021 should have received a package containing a Proxy Card attached to a Stock Order Form. These packages also include a Proxy Statement describing the plan of conversion and the charitable foundation, neither of which can be implemented without depositor approval. If you have more than one eligible account, you may receive multiple packages. Please open each package and vote all the Proxy Cards that were sent to you.

Voting does not obligate you to purchase shares of common stock during the offering.

WHAT HAPPENS IF I DON’T VOTE?

Your vote is very important. Not voting all the Proxy Cards you receive will have the same effect as voting “AGAINST” both proposals. Without sufficient favorable votes, we cannot complete the conversion and stock offering.

HOW DO I VOTE?

Mark your vote, sign and date each Proxy Card and return the card(s) in the enclosed Proxy Reply Envelope.

Alternatively, you may vote by telephone or Internet by following the simple instructions on the Proxy Card. PLEASE VOTE PROMPTLY. NOT VOTING HAS THE SAME EFFECT AS VOTING “AGAINST” BOTH PROPOSALS. Telephone and Internet voting are available 24 hours a day.

HOW MANY VOTES AM I ENTITLED TO CAST?

Depositors at the close of business on May 5, 2021 are entitled to cast one vote for each $100 or fraction thereof on deposit. No depositor may cast more than 1,000 votes. Proxy Cards are not imprinted with your number of votes; however, votes will be automatically tallied by computer.

WHY DID I RECEIVE MORE THAN ONE PROXY CARD?

If you had more than one deposit account at the close of business on May 5, 2021, you may have received more than one Proxy Card, depending on the ownership structure of your account(s). Open all packages that you receive. Please promptly vote all the Proxy Cards sent to you – they do not duplicate each other.

MORE THAN ONE NAME APPEARS ON MY PROXY CARD. WHO MUST SIGN?

The name(s) reflect the title of your account. Proxy Cards for joint accounts require the signature of only one of the account holders. Proxy Cards for trust or custodian accounts must be signed by the trustee or the custodian, not the named beneficiary.

HOW MANY SHARES ARE BEING OFFERED FOR SALE AND AT WHAT PRICE?

Blue Foundry Bancorp is offering for sale between 17,850,000 and 24,150,000 shares of common stock (subject to increase to 27,772,500 shares) at $10.00 per share. No sales commission will be charged to purchasers during the offering.

WHO IS ELIGIBLE TO PURCHASE STOCK DURING THE STOCK OFFERING?

Pursuant to our plan of conversion, non-transferable rights to subscribe for shares of Blue Foundry Bancorp common stock in the Subscription Offering have been granted in the following descending order of priority:

Shares of common stock not purchased in the Subscription Offering may be offered for sale to the public in a Community Offering, with a preference given first to natural persons and trusts of natural persons residing in Bergen, Morris, Passaic, Essex and Hudson Counties, New Jersey. Shares not sold in the Subscription and Community Offerings may be offered for sale through a Syndicated Community Offering or Firm Commitment Underwritten Offering to the general public.

I AM ELIGIBLE TO SUBSCRIBE FOR SHARES OF COMMON STOCK IN THE SUBSCRIPTION OFFERING BUT AM NOT INTERESTED IN INVESTING. MAY I ALLOW SOMEONE ELSE TO USE MY STOCK ORDER FORM TO TAKE ADVANTAGE OF MY PRIORITY AS AN ELIGIBLE ACCOUNT HOLDER?

No. Subscription rights are non-transferable! Only those eligible to subscribe in the Subscription Offering, as listed above, may purchase shares in the Subscription Offering. To preserve subscription rights, the shares may only be registered in the name(s) of eligible account holder(s). On occasion, unscrupulous people attempt to persuade account holders to transfer subscription rights, or to purchase shares in the stock offering based on an understanding that the shares will be subsequently transferred to others. Participation in such schemes is against the law and may subject involved parties to prosecution. If you become aware of any such activities, please notify our Stock Information Center promptly so that we can take the necessary steps to protect our eligible deposit account holders’ subscription rights in the stock offering.

HOW MAY I BUY SHARES DURING THE SUBSCRIPTION AND COMMUNITY OFFERINGS?

Shares can be purchased by completing an original Stock Order Form and mailing it, with full payment, so that it is received (not postmarked) before the offering deadline. You may submit your original Stock Order Form by paying for overnight delivery to the address listed on the Stock Order Form or by mail using the Stock Order Reply Envelope provided. You may also hand-deliver stock order forms to Blue Foundry Bank’s office located at 217 Rock Road, Glen Rock, New Jersey, which is open between 9:00 a.m. and 5:00 p.m., Monday, Tuesday, Wednesday and Friday, 9:00 a.m. and 6:00 p.m. on Thursday and 9:00 a.m. and 1:00 p.m. on Saturday. Hand delivered stock order forms will only be accepted at this location. Stock order forms may not be hand delivered to any other Blue Foundry Bank office. Please do not mail Stock Order Forms to any of Blue Foundry Bank’s offices.

WHAT IS THE DEADLINE FOR SUBMITTING STOCK ORDER FORMS?

To purchase shares in the Subscription and Community Offerings, you must deliver a properly completed, signed original Stock Order Form, with full payment, so that it is received (not postmarked) before 2:00 p.m., Eastern Time, on June 15, 2021. Acceptable methods for delivery of Stock Order Forms are described above.

HOW MAY I PAY FOR THE SHARES?

Payment for shares can be remitted in two ways:

By personal check, bank check or money order made payable directly to Blue Foundry Bancorp. These will be deposited upon receipt. We cannot accept wires or third party checks. Blue Foundry Bank line of credit checks may not be remitted for payment. Please do not mail cash!

By authorized withdrawal of funds from your Blue Foundry Bank deposit account(s). The Stock Order Form section titled “Method of Payment — Deposit Account Withdrawal” allows you to list the deposit account number(s) and amount(s) to be withdrawn. Funds designated for direct withdrawal must be in the account(s) at the time the Stock Order Form is received. You may not authorize direct withdrawal from accounts with check-writing privileges. Please submit a check instead. If you

request direct withdrawal from such accounts, we reserve the right to interpret that as your authorization to treat those funds as if we had received a check for the designated amount, and we will immediately withdraw the amount from your checking account(s). Also, IRA or other retirement accounts held at Blue Foundry Bank may not be listed for direct withdrawal. See information on retirement accounts below.

WILL I EARN INTEREST ON MY FUNDS?

Yes. If you pay by personal check, bank check or money order, you will earn interest at 0.05% per annum from the date payment is processed until the stock offering is completed or terminated. At that time, you will be issued a check for interest earned on these funds. If you pay for shares by authorizing a direct withdrawal from your Blue Foundry Bank deposit account(s), your funds will continue to earn interest within the account at the contractual rate until the stock offering is completed. The interest will remain in your account(s) when the designated withdrawal is made, upon completion or termination of the conversion and stock offering.

ARE THERE LIMITS TO HOW MANY SHARES I CAN ORDER?

Yes. The minimum order is 25 shares ($250). No individual may purchase more than 40,000 shares ($400,000) of common stock. Additionally, no person or entity, together with associates or persons acting in concert with such person or entity, may purchase more than 40,000 shares ($400,000) in all categories of the stock offering combined.

More detail on purchase limits, including the definition of “associate” and “acting in concert,” can be found in the Prospectus section entitled “The Conversion and Stock Offering — Additional Limitations on Common Stock Purchases.”

MAY I USE MY BLUE FOUNDRY BANK INDIVIDUAL RETIREMENT ACCOUNT (“IRA”) TO PURCHASE SHARES?

Yes. However, before you place your stock order, the funds you wish to use must be transferred to a self-directed retirement account maintained by an independent trustee or custodian, such as a brokerage firm. If you are interested in using IRA or any other retirement funds held at Blue Foundry Bank or elsewhere, please call our Stock Information Center as soon as possible for guidance, but preferably at least two weeks before the June 15, 2021 offering deadline. Your ability to use such funds for this purchase may depend on time constraints, because this type of purchase requires additional processing time, and may be subject to limitations imposed by the institution where the funds are held.

MAY I USE A LOAN FROM BLUE FOUNDRY BANK TO PAY FOR SHARES?

No. By regulation, Blue Foundry Bank cannot extend a loan for the purchase of Blue Foundry Bancorp common stock during the stock offering. Similarly, you may not use existing Blue Foundry Bank line of credit checks to purchase stock during the offering.

MAY I CHANGE MY MIND ABOUT ORDERING STOCK AFTER I SUBMIT MY STOCK ORDER?

No. After receipt, your executed Stock Order Form cannot be modified or revoked without our consent or unless the offering is terminated or is extended beyond                     , 2021 or the number of shares of common stock offered for sale is increased to more than 27,772,500 shares or decreased to less than 17,850,000 shares.

ARE DIRECTORS AND EXECUTIVE OFFICERS OF BLUE FOUNDRY BANK PLANNING TO PURCHASE STOCK?

Yes! Directors and executive officers, together with their associates, are expected to subscribe for 402,500 shares of common stock in the stock offering, representing 2.3% of the shares to be sold at the minimum of the offering range.

WILL THE STOCK BE INSURED?

No. Like any common stock, Blue Foundry Bancorp’s stock will not be insured.

WILL DIVIDENDS BE PAID ON THE STOCK?

Blue Foundry Bancorp has not made a decision with respect to the amount, if any, and timing of any dividend payments following the completion of the conversion and stock offering. The amount of dividends to be paid will be subject to our capital requirements, our financial condition and results of operations, tax considerations, statutory and regulatory limitations, and general economic conditions. We cannot assure you that we will pay dividends in the future, or that, if dividends are paid, any such dividends will not be reduced or eliminated in the future.

WILL BLUE FOUNDRY BANCORP SHARES BE LISTED ON A STOCK EXCHANGE?

Upon conclusion of the stock offering, we expect that Blue Foundry Bancorp’s shares will be listed for trading on the Nasdaq Global Select Market under the symbol “BLFY.” Once the shares have begun trading, you may contact a firm offering investment services in order to buy or sell Blue Foundry Bancorp shares in the future.

IF I PURCHASE SHARES DURING THE SUBSCRIPTION AND COMMUNITY OFFERINGS, WHEN WILL I RECEIVE MY SHARES?

All shares of Blue Foundry Bancorp common stock sold in the Subscription and Community Offerings will be issued in book entry form on the books of our transfer agent, through the Direct Registration System. Paper stock certificates will not be issued. As soon as practicable after completion of the stock offering, our transfer agent will send, by first class mail, a statement reflecting your stock ownership.

HOW CAN I GET MORE INFORMATION?

For more information, refer to the enclosed Prospectus or call our Stock Information Center, toll-free, at 1-(844) 265-9680, between 10:00 a.m. and 4:00 p.m., Eastern Time, Monday through Friday. The Stock Information Center will be closed on bank holidays.

This brochure is neither an offer to sell nor a solicitation of an offer to buy shares of common stock. The offer is made only by the Prospectus and when accompanied by a Stock Order Form. These securities are not deposits or savings accounts and are not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

The approval of a plan of conversion (the “Plan of Conversion”) whereby Blue Foundry, MHC will convert from the mutual holding company structure to the stock holding company structure and Blue Foundry Bank will become the wholly-owned subsidiary of a new stock holding company, Blue Foundry Bancorp, as described in more detail in the accompanying proxy statement (the “Conversion”);

The establishment of Blue Foundry Charitable Foundation, Inc. and the contribution to it of 750,000 shares of common stock of Blue Foundry Bancorp and $1.5 million of cash in connection with the Conversion; and

  Signature:                                                                                                                                                                    Date:                           , 2021  

VOTE BY INTERNET

(available 24 hours a day)

VOTE BY TELEPHONE

(available 24 hours a day)

myproxyvotecounts.com

Use the Internet to vote your proxy. Have the Proxy Card(s) in hand when you access the web site. You will need to enter online the 12 digit control number located in the shaded box above. Each Proxy Card has a unique control number.

1-(844) 254-8899

Have your Proxy Card(s) in hand when you access the phone voting line. You will be prompted to enter your 12 digit control number, located in the shaded box above. Each Proxy Card has a unique control number.

Mark, sign and date your Proxy Card and return it in the enclosed postage paid Proxy Reply Envelope.