UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Form 10-K

(Mark One)

For the fiscal year ended December 31, 2017

For the transition period from             to            

Commission file number 0-15752

CENTURY BANCORP, INC.

(Exact name of registrant as specified in its charter)

Registrant’s telephone number including area code:

(781) 391-4000

Securities registered pursuant to Section 12(b) of the Act:

Indicate by check mark whether the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act.    Yes  ☐    No  ☒

Indicate by check mark whether the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act.    Yes  ☐    No  ☒

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.    Yes  ☒    No  ☐

Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Web site, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulations S-T (232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files).    Yes  ☒    No  ☐

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K is not contained herein, and will not be contained, to the best of registrant’s knowledge, in definitive proxy or information statements incorporated by reference in Part III of this Form 10-K or any amendment to this Form 10-K    ☐

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

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 pursuant to Section 13(a) of the Exchange Act.    ☐

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Act).    Yes  ☐    No  ☒

State the aggregate market value of the registrant’s voting and nonvoting stock held by nonaffiliates, computed using the closing price as reported on Nasdaq as of June 30, 2017 was $230,477,369.

Indicate the number of shares outstanding of each of the registrant’s classes of common stock as of February 28, 2018:

Class A Common Stock, $1.00 par value 3,607,429 Shares

Class B Common Stock, $1.00 par value 1,960,480 Shares

DOCUMENTS INCORPORATED BY REFERENCE

List hereunder the following documents if incorporated by reference and the Part of the Form 10-K (e.g., Part I, Part II, etc.) into which the document is incorporated: (1) Any annual report to security holders; (2) Any proxy or information statement; and (3) Any prospectus filed pursuant to Rule 424(b) or (c) under the Securities Act of 1933. The listed documents should be clearly described for identification purposes (e.g., annual report to security holders for fiscal year ended December 24, 1980).

CENTURY BANCORP INC.

FORM 10-K

TABLE OF CONTENTS

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PART I

The Company

Century Bancorp, Inc. (together with its bank subsidiary, unless the context otherwise requires, the “Company”) is a Massachusetts state-chartered bank holding company headquartered in Medford, Massachusetts. The Company is a Massachusetts corporation formed in 1972 and has one banking subsidiary (the “Bank”): Century Bank and Trust Company formed in 1969. At December 31, 2017, the Company had total assets of $4.8 billion. Currently, the Company operates 27 banking offices in 20 cities and towns in Massachusetts, ranging from Braintree in the south to Andover in the north. The Bank’s customers consist primarily of small and medium-sized businesses and retail customers in these communities and surrounding areas, as well as local governments and large healthcare and higher education institutions throughout Massachusetts, New Hampshire, Rhode Island, Connecticut, and New York.

The Company’s results of operations are largely dependent on net interest income, which is the difference between the interest earned on loans and securities and interest paid on deposits and borrowings. The results of operations are also affected by the level of income and fees from loans, deposits, as well as operating expenses, the provision for loan losses, the impact of federal and state income taxes and the relative levels of interest rates and economic activity.

The Company offers a wide range of services to commercial enterprises, state and local governments and agencies, non-profit organizations and individuals. It emphasizes service to small and medium-sized businesses and retail customers in its market area. The Company makes commercial loans, real estate and construction loans and consumer loans, and accepts savings, time, and demand deposits. In addition, the Company offers to its corporate and institutional customers automated lock box collection services, cash management services and account reconciliation services, and actively promotes the marketing of these services to the municipal market. Also, the Company provides full service securities brokerage services through a program called Investment Services at Century Bank, which is supported by LPL Financial, a third party full-service securities brokerage business.

The Company has municipal cash management client engagements in Massachusetts, New Hampshire and Rhode Island comprised of approximately 250 government entities.

Availability of Company Filings

Under the Securities Exchange Act of 1934, Sections 13 and 15(d), periodic and current reports must be filed with the Securities and Exchange Commission (the “SEC”). The public may read and copy any materials filed with the SEC at the SEC’s Public Reference Room at 100 F Street, NE, Washington, DC 20549. The public may obtain information on the operation of the Public Reference Room by calling the SEC at 1-800-SEC-0030. The Company electronically files with the SEC its periodic and current reports, as well as other filings it makes with the SEC from time to time. The SEC maintains an Internet site that contains reports and other information regarding issuers, including the Company, that file electronically with the SEC, at www.sec.gov, in which all forms filed electronically may be accessed. Additionally, our annual report on Form 10-K, quarterly reports on Form 10-Q and current reports on Form 8-K and additional shareholder information are available free of charge on the Company’s website: www.centurybank.com.

Employees

As of December 31, 2017, the Company had 385 full-time and 62 part-time employees. The Company’s employees are not represented by any collective bargaining unit. The Company believes that its employee relations are good.

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Financial Services Modernization

On November 12, 1999, President Clinton signed into law The Gramm-Leach-Bliley Act (“Gramm-Leach”) which significantly altered banking laws in the United States. Gramm-Leach enables combinations among banks, securities firms and insurance companies beginning March 11, 2000. As a result of Gramm Leach, many of the depression-era laws that restricted these affiliations and other activities that may be engaged in by banks and bank holding companies were repealed. Under Gramm-Leach, bank holding companies are permitted to offer their customers virtually any type of financial service that is financial in nature or incidental thereto, including banking, securities underwriting, insurance (both underwriting and agency) and merchant banking.

In order to engage in these financial activities, a bank holding company must qualify and register with the Federal Reserve Board as a “financial holding company” by demonstrating that each of its bank subsidiaries is “well capitalized,” “well managed,” and has at least a “satisfactory” rating under the Community Reinvestment Act of 1977 (the “CRA”). The Company has not elected to become a financial holding company under Gramm-Leach.

These financial activities authorized by Gramm-Leach may also be engaged in by a “financial subsidiary” of a national or state bank, except for insurance or annuity underwriting, insurance company portfolio investments, real estate investment and development and merchant banking, which must be conducted in a financial holding company. In order for the new financial activities to be engaged in by a financial subsidiary of a national or state bank, Gramm-Leach requires each of the parent bank (and any bank affiliates) to be “well capitalized” and “well managed;” the aggregate consolidated assets of all of that bank’s financial subsidiaries may not exceed the lesser of 45% of its consolidated total assets or $50 billion; the bank must have at least a satisfactory CRA rating; and, if the bank is one of the 100 largest banks, it must meet certain financial rating or other comparable requirements. The Company does not currently conduct activities through a financial subsidiary.

Gramm-Leach establishes a system of functional regulation, under which the federal banking agencies will regulate the banking activities of financial holding companies and banks’ financial subsidiaries, the SEC will regulate their securities activities, and state insurance regulators will regulate their insurance activities. Gramm-Leach also provides new protections against the transfer and use by financial institutions of consumers’ nonpublic, personal information.

Holding Company Regulation

The Company is a bank holding company as defined by the Bank Holding Company Act of 1956, as amended (the “Holding Company Act”), and is registered as such with the Board of Governors of the Federal Reserve Bank (the “FRB”), which is responsible for administration of the Holding Company Act. Although the Company may meet the qualifications for electing to become a financial holding company under Gramm-Leach, the Company has elected to retain its pre-Gramm-Leach status for the present time under the Holding Company Act. As required by the Holding Company Act, the Company files with the FRB an annual report regarding its financial condition and operations, management and intercompany relationships of the Company and the Bank. It is also subject to examination by the FRB and must obtain FRB approval before (i) acquiring direct or indirect ownership or control of more than 5% of the voting stock of any bank, unless it already owns or controls a majority of the voting stock of that bank, (ii) acquiring all or substantially all of the assets of a bank, except through a subsidiary which is a bank, or (iii) merging or consolidating with any other bank holding company. A bank holding company must also give the FRB prior written notice before purchasing or redeeming its equity securities, if the gross consideration for the purchase or redemption, when aggregated with the net consideration paid by the company for all such purchases or redemptions during the preceding 12 months, is equal to 10% or more of the company’s consolidated net worth.

The Holding Company Act prohibits a bank holding company, with certain exceptions, from (i) acquiring direct or indirect ownership or control of more than 5% of any class of voting shares of any company which is

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not a bank or a bank holding company, or (ii) engaging in any activity other than managing or controlling banks, or furnishing services to or performing services for its subsidiaries. A bank holding company may own, however, shares of a company engaged in activities which the FRB has determined are so closely related to banking or managing or controlling banks as to be a proper incident thereto.

The Company and its subsidiaries are examined by federal and state regulators. The FRB has regulatory authority over holding company activities and performed a review of the Company and its subsidiaries as of September 2016.

USA PATRIOT Act

Under Title III of the USA PATRIOT Act, also known as the “International Money Laundering Abatement and Anti-Terrorism Act of 2001”, all financial institutions are required in general to identify their customers, adopt formal and comprehensive anti-money laundering programs, scrutinize or prohibit altogether certain transactions of special concern, and be prepared to respond to inquiries from U.S. law enforcement agencies concerning their customers and their transactions. Additional information-sharing among financial institutions, regulators, and law enforcement authorities is encouraged by the presence of an exemption from the privacy provisions of the Gramm-Leach Act for financial institutions that comply with this provision and the authorization of the Secretary of the Treasury to adopt rules to further encourage cooperation and information-sharing. The effectiveness of a financial institution in combating money laundering activities is a factor to be considered in any application submitted by the financial institution under the Holding Company Act or Bank Merger Act.

Sarbanes-Oxley Act

The Sarbanes-Oxley Act, signed into law July 30, 2002, addresses, among other issues, corporate governance, auditor independence and accounting standards, executive compensation, insider loans, whistleblower protection and enhanced and timely disclosure of corporate information. The SEC has adopted a substantial number of implementing rules and the Financial Industry Regulatory Authority (FINRA) has adopted corporate governance rules that have been approved by the SEC and are applicable to the Company. The changes are intended to allow stockholders to monitor more effectively the performance of companies and management. As directed by Section 302(a) of the Sarbanes-Oxley Act, the Company’s Chief Executive Officer and Chief Financial Officer are each required to certify that the Company’s quarterly and annual reports do not contain any untrue statement of a material fact. This requirement has several parts, including certification that these officers are responsible for establishing, maintaining and regularly evaluating the effectiveness of the Company’s disclosure controls and procedures and internal controls over financial reporting; that they have made certain disclosures to the Company’s auditors and the Board of Directors about the Company’s disclosure controls and procedures and internal control over financial reporting, and that they have included information in the Company’s quarterly and annual reports about their evaluation of the Company’s disclosure controls and procedures and internal control over financial reporting, and whether there have been significant changes in the Company’s internal disclosure controls and procedures or in other factors that could significantly affect such controls and procedures subsequent to the evaluation and whether there have been any significant changes in the Company’s internal control over financial reporting that have materially affected or reasonably likely to materially affect the Company’s internal control over financial reporting, and compliance with certain other disclosure objectives. Section 906 of the Sarbanes-Oxley Act requires an additional certification that each periodic report containing financial statements fully complies with the requirements of Section 13(a) and 15(d) of the Securities Exchange Act of 1934 and that the information in the report fairly presents, in all material respects, the financial conditions and results of operations of the Company.

Dodd-Frank Wall Street Reform and Consumer Protection Act

On July 21, 2010, the Dodd-Frank Wall Street Reform and Consumer Protection Act (the “Act”) became law. The Act was intended to address many issues arising in the recent financial crisis and is exceedingly broad

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in scope, affecting many aspects of bank and financial market regulation. The Act requires, or permits by implementing regulation, enhanced prudential standards for banks and bank holding companies inclusive of capital, leverage, liquidity, concentration and exposure measures. In addition, traditional bank regulatory principles such as restrictions on transactions with affiliates and insiders were enhanced. The Act also contains reforms of consumer mortgage lending practices and creates a Bureau of Consumer Financial Protection, which is granted broad authority over consumer financial practices of banks and others. It is expected as the specific new or incremental requirements applicable to the Company become effective that the costs and difficulties of remaining compliant with all such requirements will increase. The Act broadened the base for FDIC assessments to average consolidated assets less tangible equity of financial institutions and also permanently raises the current standard maximum FDIC deposit insurance amount to $250,000. The Act extended unlimited deposit insurance on non-interest bearing transaction accounts through December 31, 2012. In addition, the Act added a new Section 13 to the Bank Holding Company Act, the so-called “Volcker Rule,” (the “Rule”) which generally restricts certain banking entities such as the Company and its subsidiaries or affiliates, from engaging in proprietary trading activities and owning equity in or sponsoring any private equity or hedge fund. The Rule became effective July 21, 2012. The final implementing regulations for the Rule were issued by various regulatory agencies in December, 2013 and under an extended conformance regulation compliance must be achieved by July 21, 2015. The conformance period for investments in and relationships with certain “legacy covered funds” was extended to July 21, 2016 and was extended further to July 31, 2017. Under the Rule, the Company may be restricted from engaging in proprietary trading, investing in third party hedge or private equity funds or sponsoring new funds unless it qualifies for an exemption from the rule. The Company has little involvement in prohibited proprietary trading or investment activities in covered funds and the Company does not expect that complying with the requirements of the Rule will have any material effect on the Company’s financial condition or results of operation.

Tax Cuts and Jobs Act

On December 22, 2017, the Tax Cuts and Jobs Act (the “Tax Act”) was enacted, which represents the most comprehensive reform to the U.S. tax code in over thirty years. The majority of the provisions of the Tax Act take effect on January 1, 2018. The Tax Act lowers the Company’s federal tax rate from 34% to 21%. Also, for tax years beginning after December 31, 2017, the corporate Alternative Minimum Tax (“AMT”) has been repealed. For 2018 through 2021, the AMT credit carryforward can offset regular tax liability and is refundable in an amount equal to 50% (100% for 2021) of the excess of the minimum tax credit for the tax year over the amount of the credit allowable for the year against regular tax liability. Accordingly, the full amount of the alternative minimum tax credit carryforward will be recovered in tax years beginning before 2022. The Tax Act also contains other provisions that may affect the Company currently or in future years. Among these are changes to the deductibility of meals and entertainment, the deductibility of executive compensation, the dividend received deduction and net operating loss carryforwards.

Deposit Insurance Premiums

The Bank’s deposits have the benefit of FDIC insurance up to applicable limits. The FDIC’s Deposit Insurance Fund is funded by assessments on insured depository institutions, which depend on the risk category of an institution and the amount of assets that it holds. The FDIC may increase or decrease the assessment rate schedule on a semi-annual basis.

On September 29, 2009, the FDIC adopted a Notice of Proposed Rulemaking (NPR) that required insured institutions to prepay their estimated quarterly risk-based assessments for the fourth quarter of 2009 and for all of 2010, 2011 and 2012. The FDIC Board voted to adopt a uniform three-basis point increase in assessment rates effective on January 1, 2011, and extend the restoration period from seven to eight years. This rule was finalized on November 2, 2009. The Company’s quarterly risk-based deposit insurance assessments were paid from this amount until June 30, 2013. The Company received a refund of $2.4 million of prepaid FDIC assessments in June 2013.

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In February 2011, the FDIC approved a rule to change the assessment base from adjusted domestic deposits to average consolidated total assets minus average tangible equity. The rule has kept the overall amount collected from the industry very close to the amount collected prior to the new calculation.

Risk-Based Capital Guidelines

Federal banking regulators have issued risk-based capital guidelines, which assign risk factors to asset categories and off-balance-sheet items. Also, the Basel Committee has issued capital standards entitled “Basel III: A global regulatory framework for more resilient banks and banking systems” (“Basel III”). The Federal Reserve Board has finalized its rule implementing the Basel III regulatory capital framework. The rule that came into effect in January 2015 sets the Basel III minimum regulatory capital requirements for all organizations. It includes a new common equity Tier I ratio of 4.5 percent of risk-weighted assets, raises the minimum Tier I capital ratio from 4 percent to 6 percent of risk-weighted assets and would set a new conservation buffer of 2.5 percent of risk-weighted assets. The implementation of the framework did not have a material impact on the Company’s financial condition or results of operations.

Competition

The Company experiences substantial competition in attracting deposits and making loans from commercial banks, thrift institutions and other enterprises such as insurance companies and mutual funds. These competitors include several major commercial banks whose greater resources may afford them a competitive advantage by enabling them to maintain numerous branch offices and mount extensive advertising campaigns. A number of these competitors are not subject to the regulatory oversight that the Company is subject to, which increases these competitors’ flexibility.

Forward-Looking Statements

Certain statements contained herein are not based on historical facts and are “forward-looking statements” within the meaning of Section 21A of the Securities Exchange Act of 1934. Forward-looking statements, which are based on various assumptions (some of which are beyond the Company’s control), may be identified by reference to a future period or periods, or by the use of forward-looking terminology, such as “may,” “will,” “believe,” “expect,” “estimate,” “anticipate,” “continue” or similar terms or variations on those terms, or the negative of these terms. Actual results could differ materially from those set forth in forward-looking statements due to a variety of factors, including, but not limited to, those related to the economic environment, particularly in the market areas in which the Company operates, competitive products and pricing, fiscal and monetary policies of the U.S. Government, changes in government regulations affecting financial institutions, including regulatory fees and capital requirements, changes in prevailing interest rates, acquisitions and the integration of acquired businesses, credit risk management, asset/liability management, the financial and securities markets, and the availability of and costs associated with sources of liquidity.

The Company does not undertake, and specifically disclaims any obligation, to publicly release the result of any revisions which may be made to any forward-looking statements to reflect the occurrence of anticipated or unanticipated events or circumstances after the date of such statements.

The risk factors that may affect the Company’s performance and results of operations include the following:

(i) the Company’s business is dependent upon general economic conditions in Massachusetts, New Hampshire, Rhode Island, Connecticut, and New York. The national and local economies may adversely affect the Company’s performance and results of operations;

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(ii) the Company’s earnings depend, to a great extent, upon the level of net interest income generated by the Company, and therefore the Company’s results of operations may be adversely affected by increases or decreases in interest rates or by the shape of the yield curve;

(iii) the banking business is highly competitive and the profitability of the Company depends upon the Company’s ability to attract loans and deposits in Massachusetts, New Hampshire, Rhode Island, Connecticut, and New York, where the Company competes with a variety of traditional banking companies, some of which have vastly greater resources, and nontraditional institutions such as credit unions and finance companies; .

(iv) at December 31, 2017, approximately 68.8% of the Company’s loan portfolio was comprised of commercial and commercial real estate loans, exposing the Company to the risks inherent in financings based upon analyses of credit risk, the value of underlying collateral, including real estate, and other more intangible factors, which are considered in making commercial loans;

(v) at December 31, 2017, approximately 24.6% of the Company’s loan portfolio was comprised of residential real estate and home equity loans, exposing the Company to the risks inherent in financings based upon analyses of credit risk and the value of underlying collateral. Accordingly, the Company’s profitability may be negatively impacted by errors in risk analyses, by loan defaults and the ability of certain borrowers to repay such loans may be adversely affected by any downturn in general economic conditions;

(vi) economic conditions and interest rate risk could adversely impact the fair value and the ultimate collectibility of the Company’s investments. Should an investment be deemed “other than temporarily impaired”, the Company would be required to writedown the carrying value of the investment through earnings. Such writedown(s) may have a material adverse effect on the Company’s financial condition and results of operations;

(vii) writedown of goodwill and other identifiable intangible assets would negatively impact our financial condition and results of operations. At December 31, 2017, our goodwill and other identifiable intangible assets were approximately $2.7 million;

(viii) acts or threats of terrorism and actions taken by the United States or other governments as a result of such acts or threats, including possible military action, could further adversely affect business and economic conditions in the United States of America generally and in the Company’s markets, which could adversely affect the Company’s financial performance and that of the Company’s borrowers and on the financial markets and the price of the Company’s Class A common stock;

(ix) changes in the extensive laws, regulations and policies governing companies generally and bank holding companies and their subsidiaries, such as the Act and the Tax Act, could alter the Company’s business environment or affect the Company’s operations;

(x) the potential need to adapt to industry changes in information technology systems, on which the Company is highly dependent to secure bank and customer financial information, could present operational issues, require significant capital spending or impact the Company’s reputation;

(xi) evolving information technologies, the need to mitigate against and react to cyber-security risks and electronic fraud risks require significant resources and notwithstanding our investment in resources, we remain subject to cyber security risks and electronic fraud;

(xii) the Company’s loan customers may not repay loans according to their terms, and the collateral securing the payment of loans may be insufficient to assure repayment or cover losses. If loan customers fail to repay loans according to the terms of the loans, the Company may experience significant credit losses which could have a material adverse effect on its operating results and capital ratios;

(xiii) the Company is subject to extensive regulation, supervision and examination. Any change in the laws or regulations or failure by the Company to comply with applicable law and regulation, or a change in regulators’ supervisory policies or examination procedures, whether by the Massachusetts Commissioner of

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Banks, the FDIC, the Federal Reserve Board, other state or federal regulators, the United States Congress, or the Massachusetts legislature could have a material adverse effect on the Company’s business, financial condition, results of operations, and cash flows. Changes in accounting policies, practices and standards, as may be adopted by the regulatory agencies as well as the Public Company Accounting Oversight Board, the Financial Accounting Standards Board, and other accounting standard setters, could also impact the Company’s financial results; and

These factors, as well as general economic and market conditions in the United States of America, may materially and adversely affect the Company’s performance, results of operations and the market price of shares of the Company’s Class A common stock.

No written comments received by the Company from the SEC regarding the Company’s periodic or current reports remain unresolved.

The Company owns its main banking office, headquarters, and operations center in Medford, Massachusetts, which were expanded in 2004, and 11 of the 26 other facilities in which its branch offices are located. The remaining offices are occupied under leases expiring on various dates from 2018 to 2028. The Company believes that its banking offices are in good condition.

During June 2016, the Company entered into a lease agreement to open a new branch located in Wellesley, Massachusetts. The Company closed its existing Wellesley branch and transferred the accounts to the new Wellesley branch which opened on December 19, 2016. On September 25, 2017 the Company purchased the new Wellesley location.

The Company and its subsidiaries are parties to various claims and lawsuits arising in the course of their normal business activities. Although the ultimate outcome of these suits cannot be ascertained at this time, it is the opinion of management that none of these matters, even if it resolved adversely to the Company, will have a material adverse effect on the Company’s consolidated financial position.

On September 7, 2017, Crimson Galeria Limited Partnership, Raj & Raj, LLC, Harvard Square Holdings LLC, and Charles River Holdings LLC (collectively, the “Plaintiffs”) filed suit in the United States District Court for the District of Massachusetts against the Attorney General of the Commonwealth of Massachusetts, the Massachusetts Department of Public Health, the City of Cambridge, the Town of Georgetown, as well as against the Bank, Healthy Pharms, Inc., (“Healthy Pharms”), Timbuktu Real Estate, LLC, Paul Overgaag, Nathaniel Averill, 4Front Advisors, LLC, 4Front Holdings LLC, Kristopher T. Krane, 3 Brothers Real Estate, LLC, Red Line Management, LLC, unspecified insurance providers to certain Plaintiffs, Tomolly, Inc., and (collectively, the “Defendants”).

The Plaintiffs allege that they own property in Cambridge, MA, and claim that the value and use of their property will be impaired by Healthy Pharms decision to open a registered medicinal marijuana dispensary in abutting or nearby situated property. The Plaintiffs further allege that the Bank has a banking relationship with Healthy Pharms and that, by entering into such relationship, the Bank conspired with Healthy Pharms to violate the Racketeer Influenced and Corrupt Organizations Act, 18 U.S.C. § 1961 et seq. The Plaintiffs seek unspecified treble damages and attorney’s costs and fees, as well as injunctive and declaratory relief.

The Company believes that the claims and allegations against the Bank set forth in the complaint are without merit, and the Company and the Bank intend to vigorously defend against them.

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On December 15, 2017, the Company filed a motion to dismiss the complaint; the plaintiffs filed an opposition brief, and the Company has filed a reply in further support of its motion.

Not applicable.

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PART II

(a) The Class A Common Stock of the Company is traded on the NASDAQ National Global Market under the symbol “CNBKA.” The price range of the Company’s Class A common stock since January 1, 2016 is shown on page 14. The Company’s Class B Common Stock is not traded on any national securities exchange or other public trading market.

The shares of Class A Common Stock are generally not entitled to vote on any matter, including in the election of Company Directors, but, in limited circumstances, may be entitled to vote as a class on certain extraordinary transactions, including any merger or consolidation (other than one in which the Company is the surviving corporation or one which by law may be approved by the directors without any stockholder vote) or the sale, lease, or exchange of all or substantially all of the property and assets of the Company. Since the vote of a majority of the shares of the Company’s Class B Common Stock, voting as a separate class, is required to approve certain extraordinary corporate transactions, the holders of Class B Common Stock have the power to prevent any takeover of the Company not approved by them.

(b) Approximate number of equity security holders as of December 31, 2017:

(c) Under the Company’s Articles of Organization, the holders of Class A Common Stock are entitled to receive dividends per share equal to at least 200% of dividends paid, if any, from time to time, on each share of Class B Common Stock.

The following table shows the dividends paid by the Company on the Class A and Class B Common Stock for the periods indicated.

The Company’s ability to pay dividends on its shares depends generally on dividends it receives from the Bank. Both Massachusetts and federal law limit the payment of dividends by the Bank to the Company. Under FDIC regulations and applicable Massachusetts law, the dollar amount of dividends and any other capital distributions that the Bank may make depends upon its capital position and recent net income. Generally, so long as the Bank remains adequately capitalized, it may potentially make capital distributions during any calendar year equal to up to 100% of net income for the year to date plus retained net income for the two preceding years. However, if the Bank’s capital becomes impaired or the FDIC or Commissioner otherwise determines that the Bank should conserve capital, the Bank may be prohibited or otherwise limited from paying any dividends or making any other capital distributions.

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The Federal Reserve Board also has authority to prohibit dividends by bank holding companies such as the Company, if their actions constitute unsafe or unsound practices. Prior to the recent financial crisis, the Federal Reserve Board issued a policy statement and supervisory guidance on the payment of cash dividends by bank holding companies, which expresses the Federal Reserve Board’s view that a bank holding company should pay cash dividends only to the extent that, (1) the company’s net income for the past year is sufficient to cover the cash dividends, (2) the rate of earnings retention is consistent with the company’s capital needs, asset quality, and overall financial condition, and (3) the minimum regulatory capital adequacy ratios are met. It is also the Federal Reserve Board’s policy that bank holding companies should not maintain dividend levels that undermine their ability to serve as a source of strength to their banking subsidiaries. It is expected that the Federal Reserve Board will be more rather than less restrictive for the foreseeable future about dividend practices.

(d) The following schedule provides information with respect to the Company’s equity compensation plans under which shares of Class A Common Stock are authorized for issuance as of December 31, 2017:

(e) The performance graph information required herein is shown on page 13.

The information required herein is shown on pages 13 through 15.

The information required herein is shown on pages 16 through 39.

The information required herein is shown on pages 37.

The information required herein is shown on pages 40 through 95.

None.

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The Company’s principal executive officer and principal financial officer have evaluated the Company’s disclosure controls and procedures as of December 31, 2017. Based on this evaluation, the principal executive officer and principal financial officer have concluded that the Company’s disclosure controls and procedures are effective. The Company’s disclosure controls and procedures also effectively ensure that information required to be disclosed in the Company’s filings and submissions with the Securities and Exchange Commission under the Securities Exchange Act of 1934 is accumulated and reported to Company management (including the principal executive officer and principal financial officer) and is recorded, processed, summarized and reported within the time periods specified by the Securities and Exchange Commission. In addition, the Company has reviewed its internal control over financial reporting and there have been no changes that occurred during the fourth fiscal quarter that have materially affected, or are reasonably likely to materially affect its internal control over financial reporting or in other factors that could significantly affect its internal control over financial reporting.

On May 14, 2013, the Committee of Sponsoring Organizations of the Treadway Commission (COSO) released an updated version of its Internal Control — Integrated Framework (2013) (2013 Framework). The 2013 Framework’s internal control components (i.e., control environment, risk assessment, control activities, information and communication, and monitoring activities) remain predominantly the same as those in the 1992 Framework. However, the 2013 Framework was expanded to include 17 principles which must be present and functioning in order to have an effective system of internal controls. The Company implemented the 2013 Framework effective December 31, 2014.

Management’s report on internal control over financial reporting is shown on page 98. The audit report of the registered public accounting firm is shown on page 97.

None.

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FINANCIAL STATEMENTS

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Financial Highlights

13

Financial Highlights — (Continued)

The stock performance graph below compares the cumulative total shareholder return of the Company’s Class A Common Stock from December 31, 2012 to December 31, 2017 with the cumulative total return of the NASDAQ Market Index (U.S. Companies) and the NASDAQ Bank Stock Index. The lines in the graph represent monthly index levels derived from compounded daily returns that include all dividends. If the monthly interval, based on the fiscal year-end, was not a trading day, the preceding trading day was used.

14

Financial Highlights — (Continued)

Comparison of Five-Year

Cumulative Total Return*

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Management’s Discussion and Analysis of Results of Operations and Financial Condition

FORWARD-LOOKING STATEMENTS

Certain statements contained herein are not based on historical facts and are “forward-looking statements” within the meaning of Section 21A of the Securities Exchange Act of 1934. Forward-looking statements, which are based on various assumptions (some of which are beyond the Company’s control), may be identified by reference to a future period or periods, or by the use of forward-looking terminology, such as “may,” “will,” “believe,” “expect,” “estimate,” “anticipate,” “continue” or similar terms or variations on those terms, or the negative of these terms. Actual results could differ materially from those set forth in forward-looking statements due to a variety of factors, including, but not limited to, those related to the economic environment, particularly in the market areas in which the Company operates, competitive products and pricing, fiscal and monetary policies of the U.S. Government, changes in government regulations affecting financial institutions, including regulatory fees and capital requirements, changes in prevailing interest rates, acquisitions and the integration of acquired businesses, credit risk management, asset/liability management, the financial and securities markets, and the availability of and costs associated with sources of liquidity.

The Company does not undertake, and specifically disclaims any obligation, to publicly release the result of any revisions which may be made to any forward-looking statements to reflect the occurrence of anticipated or unanticipated events or circumstances after the date of such statements.

RECENT MARKET DEVELOPMENTS

On July 21, 2010, the Dodd-Frank Wall Street Reform and Consumer Protection Act (the “Act”) became law. The Act was intended to address many issues arising in the recent financial crisis and is exceedingly broad in scope, affecting many aspects of bank and financial market regulation. The Act requires, or permits by implementing regulation, enhanced prudential standards for banks and bank holding companies inclusive of capital, leverage, liquidity, concentration and exposure measures. In addition, traditional bank regulatory principles such as restrictions on transactions with affiliates and insiders were enhanced. The Act also contains reforms of consumer mortgage lending practices and creates a Bureau of Consumer Financial Protection, which is granted broad authority over consumer financial practices of banks and others. It is expected as the specific new or incremental requirements applicable to the Company become effective that the costs and difficulties of remaining compliant with all such requirements will increase. The Act broadened the base for FDIC assessments to average consolidated assets less tangible equity of financial institutions and also permanently raises the current standard maximum FDIC deposit insurance amount to $250,000. The Act extended unlimited deposit insurance on non-interest bearing transaction accounts through December 31, 2012.

In addition, the Act added a new Section 13 to the Bank Holding Company Act, the so-called “Volcker Rule,” (the “Rule”) which generally restricts certain banking entities such as the Company and its subsidiaries or affiliates, from engaging in proprietary trading activities and owning equity in or sponsoring any private equity or hedge fund. The Rule became effective July 21, 2012. The final implementing regulations for the Rule were issued by various regulatory agencies in December, 2013 and under an extended conformance regulation compliance was required to be achieved by July 21, 2015. The conformance period for investments in and relationships with certain “legacy covered funds” has been extended to July 21, 2017. Under the Rule, the Company may be restricted from engaging in proprietary trading, investing in third party hedge or private equity funds or sponsoring new funds unless it qualifies for an exemption from the rule. The Company has little involvement in prohibited proprietary trading or investment activities in covered funds and the Company does not expect that complying with the requirements of the Rule will have any material effect on the Company’s financial condition or results of operation.

Federal banking regulators have issued risk-based capital guidelines, which assign risk factors to asset categories and off-balance-sheet items. Also, the Basel Committee has issued capital standards entitled “Basel III: A global regulatory framework for more resilient banks and banking systems” (“Basel III”). The Federal Reserve Board has finalized its rule implementing the Basel III regulatory capital framework. The rule

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Management’s Discussion and Analysis of Results of Operations and Financial Condition — (Continued)

that came into effect in January 2015 sets the Basel III minimum regulatory capital requirements for all organizations. It included a new common equity Tier I ratio of 4.5 percent of risk-weighted assets, raised the minimum Tier I capital ratio from 4 percent to 6 percent of risk-weighted assets and would set a new conservation buffer of 2.5 percent of risk-weighted assets. The implementation of the framework did not have a material impact on the Company’s financial condition or results of operations.

On December 22, 2017, the Tax Cuts and Jobs Act (the “Tax Act”) was enacted, which represents the most comprehensive reform to the U.S. tax code in over thirty years. The majority of the provisions of the Tax Act takes effect on January 1, 2018. The Tax Act lowers the Company’s federal tax rate from 34% to 21%. Also, for tax years beginning after December 31, 2017, the corporate Alternative Minimum Tax (“AMT”) has been repealed. For 2018 through 2021, the AMT credit carryforward can offset regular tax liability and is refundable in an amount equal to 50% (100% for 2021) of the excess of the minimum tax credit for the tax year over the amount of the credit allowable for the year against regular tax liability. Accordingly, the full amount of the alternative minimum tax credit carryforward will be recovered in tax years beginning before 2022. The Tax Act also contains other provisions that may affect the Company currently or in future years. Among these are changes to the deductibility of meals and entertainment, the deductibility of executive compensation, the dividend received deduction and net operating loss carryforwards. Tax Act changes for individuals include lower tax rates, mortgage interest and state and local tax limitations as well as an increase in the standard deduction, among others.

OVERVIEW

Century Bancorp, Inc. (together with its bank subsidiary, unless the context otherwise requires, the “Company”) is a Massachusetts state-chartered bank holding company headquartered in Medford, Massachusetts. The Company is a Massachusetts corporation formed in 1972 and has one banking subsidiary (the “Bank”): Century Bank and Trust Company formed in 1969. At December 31, 2017, the Company had total assets of $4.8 billion. Currently, the Company operates 27 banking offices in 20 cities and towns in Massachusetts, ranging from Braintree in the south to Andover in the north. The Bank’s customers consist primarily of small and medium-sized businesses and retail customers in these communities and surrounding areas, as well as local governments and large healthcare and higher education institutions throughout Massachusetts, New Hampshire, Rhode Island, Connecticut and New York.

The Company’s results of operations are largely dependent on net interest income, which is the difference between the interest earned on loans and securities and interest paid on deposits and borrowings. The results of operations are also affected by the level of income and fees from loans, deposits, as well as operating expenses, the provision for loan losses, the impact of federal and state income taxes and the relative levels of interest rates and economic activity.

The Company offers a wide range of services to commercial enterprises, state and local governments and agencies, non-profit organizations and individuals. It emphasizes service to small and medium sized businesses and retail customers in its market area. In recent years, the Company has increased business to larger institutions, specifically, healthcare and higher education. The Company makes commercial loans, real estate and construction loans and consumer loans, and accepts savings, time, and demand deposits. In addition, the Company offers its corporate and institutional customers automated lock box collection services, cash management services and account reconciliation services, and actively promotes the marketing of these services to the municipal market. Also, the Company provides full service securities brokerage services through a program called Investment Services at Century Bank, which is supported by LPL Financial, a third party full-service securities brokerage business.

The Company has municipal cash management client engagements in Massachusetts, New Hampshire and Rhode Island comprised of approximately 250 government entities.

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Management’s Discussion and Analysis of Results of Operations and Financial Condition — (Continued)

The Company had net income of $22,301,000 for the year ended December 31, 2017, compared with net income of $24,534,000 for the year ended December 31, 2016 and net income of $23,021,000 for the year ended December 31, 2015. Class A diluted earnings per share were $4.01 in 2017 compared to $4.41 in 2016 and compared to $4.13 in 2015.

During 2017, the Company’s earnings were negatively impacted by a reduction in the value of its net deferred tax asset resulting in a charge of $8.4 million to income tax expense. This was the result of the enactment of the Tax Act on December 22, 2017, which lowered the Company’s federal tax rate from 34% to 21%. During 2017 and 2016, the Company’s earnings were positively impacted primarily by an increase in net interest income. This increase was primarily due to an increase in earning assets. Also contributing to the increase in earnings for 2016 was a decrease in the provision for loan losses. This was primarily the result of changes in the risk profile of the Company’s new loan originations, related methodology enhancements to address these changes, as well as net recoveries being realized during the year. During 2016 and 2015, the U.S. economy experienced a low short-term rate environment. The lower short-term rates negatively impacted the net interest margin as the rate at which short-term deposits could be invested declined more than the rates offered on those deposits.

Earnings per share (EPS) for each class of stock and for each year ended December 31, is as follows:

The trends in the net interest margin are illustrated in the graph below:

Net Interest Margin

During the second and third quarters of 2015 the net interest margin increased primarily as a result of an increase in higher yielding assets as well as prepayment penalties collected. The increase in higher yielding assets was primarily the result of increased purchases of securities held-to-maturity. The margin decreased during the fourth quarter of 2015 primarily as a result of lower yielding loan originations. The margin increased during the first quarter of 2016 primarily as a result of an increase in rates on earning assets. The margin decreased during the second, third, and fourth quarters of 2016 primarily as a result of a decrease in rates on earning assets. The margin increased during 2017 primarily as a result of an increase in rates on earning assets. This increase was primarily the result of the yield on floating rate assets increasing as a result of recent increases in short term interest rates as well as an increase in prepayment penalties collected during the second quarter of 2017. Prepayment penalties collected amounted to $825,000 and contributed approximately seven basis points to the net interest margin for the second quarter. During 2017, the Company has not seen a corresponding increase in short term rates on interest bearing liabilities. While management will continue its efforts to improve the net

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Management’s Discussion and Analysis of Results of Operations and Financial Condition — (Continued)

interest margin, there can be no assurance that certain factors beyond its control, such as the prepayment of loans and changes in market interest rates, will continue to positively impact the net interest margin.

Historical U.S. Treasury Yield Curve

A yield curve is a line that typically plots the interest rates of U.S. Treasury Debt, which have different maturity dates but the same credit quality, at a specific point in time. The three main types of yield curve shapes are normal, inverted and flat. Over the past three years, the U.S. economy has experienced low short-term rates. During 2016 and 2017, short-term rates increased more than longer-term rates resulting in a flattening of the yield curve. This flattening of the yield curve became more pronounced during 2017.

Total assets were $4,785,572,000 at December 31, 2017, an increase of 7.2% from total assets of $4,462,608,000 at December 31, 2016.

On December 31, 2017, stockholders’ equity totaled $260,297,000, compared with $240,041,000 on December 31, 2016. Book value per share increased to $46.75 at December 31, 2017, from $43.11 on December 31, 2016.

During June 2016, the Company entered into a lease agreement to open a new branch located in Wellesley, Massachusetts. The Company closed its existing Wellesley branch and transferred the accounts to the new Wellesley branch which opened on December 19, 2016. On September 25, 2017 the Company purchased the new Wellesley location.

CRITICAL ACCOUNTING POLICIES

Accounting policies involving significant judgments and assumptions by management, which have, or could have, a material impact on the carrying value of certain assets and impact income, are considered critical accounting policies.

The Company considers allowance for loan losses and income taxes to be its critical accounting policies.

Allowance for Loan Losses

Arriving at an appropriate level of allowance for loan losses necessarily involves a high degree of judgment. Management maintains an allowance for loan losses to absorb losses inherent in the loan portfolio. The allowance is based on assessments of the probable estimated losses inherent in the loan portfolio. Management’s methodology for assessing the appropriateness of the allowance consists of several key elements, which include the specific allowances, if appropriate, for identified problem loans, formula allowance, and possibly an unallocated allowance. Arriving at an appropriate level of allowance for loan losses necessarily involves a high degree of judgment.

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Management’s Discussion and Analysis of Results of Operations and Financial Condition — (Continued)

Specific allowances for loan losses entail the assignment of allowance amounts to individual loans on the basis of loan impairment. Under this method, loans are selected for evaluation based upon a change in internal risk rating, occurrence of delinquency, loan classification or nonaccrual status. The formula allowances are based on evaluations of homogenous loans to determine the allocation appropriate within each portfolio segment. Formula allowances are based on internal risk ratings or credit ratings from external sources. After considering the above components, an unallocated component may be generated to cover uncertainties that could affect management’s estimate of probable losses. Further information regarding the Company’s methodology for assessing the appropriateness of the allowance is contained within Note 1 of the “Notes to Consolidated Financial Statements”.

During 2016 and 2017, the Company continued to enhance its methodology to the allowance for loan losses by updating qualitative factors on certain loan portfolios. Management believes that the allowance for loan losses is adequate. In addition, various regulatory agencies, as part of the examination process, periodically review the Company’s allowance for loan losses. Such agencies may require the Company to recognize additions to the allowance based on their judgments about information available to them at the time of their examination.

Income Taxes

Certain areas of accounting for income taxes require management’s judgment, including determining the expected realization of deferred tax assets and the adequacy of liabilities for uncertain tax positions. Judgments are made regarding various tax positions, which are often subjective and involve assumptions about items that are inherently uncertain. If actual factors and conditions differ materially from estimates made by management, the actual realization of the net deferred tax assets or liabilities for uncertain tax positions could vary materially from the amounts previously recorded.

Deferred tax assets arise from items that may be used as a tax deduction or credit in future income tax returns, for which a financial statement tax benefit has already been recognized. The realization of the net deferred tax asset generally depends upon future levels of taxable income. Valuation allowances are recorded against those deferred tax assets determined not likely to be realized. Deferred tax liabilities represent items that will require a future tax payment. They generally represent tax expense recognized in the Company’s financial statements for which payment has been deferred, or a deduction taken on the Company’s tax return but not yet recognized as an expense in the Company’s financial statements. Deferred tax liabilities are also recognized for certain non-cash items such as goodwill.

FINANCIAL CONDITION

Investment Securities

The Company’s securities portfolio consists of securities available-for-sale (“AFS”) and securities held-to-maturity (“HTM”).

Securities available-for-sale consist of certain U.S. Treasury, U.S. Government Sponsored Enterprises, SBA Backed Securities, and U.S. Government Sponsored Enterprise mortgage-backed securities; state, county and municipal securities; privately issued mortgage-backed securities; other debt securities; and other marketable equities.

These securities are carried at fair value, and unrealized gains and losses, net of applicable income taxes, are recognized as a separate component of stockholders’ equity. The fair value of securities available-for-sale at December 31, 2017 totaled $397,475,000 and included gross unrealized gains of $860,000 and gross unrealized losses of $948,000. A year earlier, the fair value of securities available-for-sale was $499,297,000 including gross unrealized gains of $555,000 and gross unrealized losses of $1,478,000. In 2017, the Company recognized gains of $47,000 on the sale of available-for-sale securities. In 2016 and 2015, the Company recognized gains of $52,000 and $289,000, respectively.

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Management’s Discussion and Analysis of Results of Operations and Financial Condition — (Continued)

Securities classified as held-to-maturity consist of U.S. Government Sponsored Enterprises, SBA Backed Securities, and U.S. Government Sponsored Enterprise mortgage-backed securities. Securities held-to-maturity as of December 31, 2017 are carried at their amortized cost of $1,701,233,000. A year earlier, securities held-to-maturity totaled $1,653,986,000. In 2017 the company did not recognize any gains on the sale of held-to-maturity securities. In 2016 and 2015 the company recognized gains of $12,000 and $305,000, respectively, on the sale of held-to-maturity securities. The sales from securities held-to-maturity relate to certain mortgage-backed securities for which the Company had previously collected a substantial portion of its principal investment.

The following table sets forth the fair value and percentage distribution of securities available-for-sale at the dates indicated.

Fair Value of Securities Available-for-Sale

The majority of the Company’s securities AFS are classified as Level 2, as defined in Note 1 of the “Notes to Consolidated Financial Statements.” The fair values of these securities are obtained from a pricing service, which provides the Company with a description of the inputs generally utilized for each type of security. These inputs include benchmark yields, reported trades, broker/dealer quotes, issuer spreads, two-sided markets, benchmark securities, bids, offers and reference data. Management’s understanding of a pricing service’s pricing methodologies includes obtaining an understanding of the valuation risks, assessing its qualification, verification of sources of information and processes used to develop prices and identifying, documenting, and testing controls. Management’s validation of a vendor’s pricing methodology includes establishing internal controls to determine that the pricing information received by a pricing service and used by management in the valuation process is relevant and reliable. Market indicators and industry and economic events are also monitored. The decline in fair value from amortized cost for individual available-for-sale securities that are temporarily impaired is not attributable to changes in credit quality. Because the Company does not intend to sell any of its debt securities and it is not more likely than not that it will be required to sell the debt securities before the anticipated recovery of their remaining amortized cost, the Company does not consider these investments to be other-than-temporarily impaired at December 31, 2017.

The increase in SBA Backed Securities was primarily the result of an increased investment return combined with a lower risk rating in these types of securities. The decrease in Obligations Issued by States and Political

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Management’s Discussion and Analysis of Results of Operations and Financial Condition — (Continued)

Subdivisions was primarily the result of increased competition in the bidding process for these types of securities.

Securities available-for-sale totaling $82,600,000, or 1.7% of assets, are classified as Level 3, as defined in Note 1 of the “Notes to Consolidated Financial Statements.” These securities are generally municipal securities with no readily determinable fair value. The Company also utilizes internal pricing analysis on various municipal securities using market rates on comparable securities. The securities are carried at fair value with periodic review of underlying financial statements and credit ratings to assess the appropriateness of these valuations.

Debt securities of Government Sponsored Enterprises refer primarily to debt securities of Fannie Mae and Freddie Mac.

The following table sets forth the amortized cost and percentage distribution of securities held-to-maturity at the dates indicated.

Amortized Cost of Securities Held-to-Maturity

The following two tables set forth contractual maturities of the Bank’s securities portfolio at December 31, 2017. Actual maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties.

Fair Value of Securities Available-for-Sale Amounts Maturing

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Management’s Discussion and Analysis of Results of Operations and Financial Condition — (Continued)

Amortized Cost of Securities Held-to-Maturity Amounts Maturing

At December 31, 2017 and 2016, the Bank had no investments in obligations of individual states, counties, municipalities or nongovernment corporate entities which exceeded 10% of stockholders’ equity. In 2017, sales of securities totaling $18,180,000 in gross proceeds resulted in a net realized gain of $47,000. In 2016, sales of securities totaling $2,568,000 in gross proceeds resulted in a net realized gain of $64,000. There were no sales of state, county or municipal securities during 2017 and 2016.

Management reviews the investment portfolio for other-than-temporary impairment of individual securities on a regular basis. The results of such analysis are dependent upon general market conditions and specific conditions related to the issuers of our securities.

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Management’s Discussion and Analysis of Results of Operations and Financial Condition — (Continued)

Loans

The Company’s lending activities are conducted principally in Massachusetts, New Hampshire, Rhode Island, Connecticut and New York. The Company grants single-family and multi-family residential loans, commercial and commercial real estate loans, municipal loans, and a variety of consumer loans. To a lesser extent, the Company grants loans for the construction of residential homes, multi-family properties, commercial real estate properties and land development. Most loans granted by the Company are secured by real estate collateral. The ability and willingness of commercial real estate, commercial, construction, residential and consumer loan borrowers to honor their repayment commitments are generally dependent on the health of the real estate market in the borrowers’ geographic areas and of the general economy.

The following summary shows the composition of the loan portfolio at the dates indicated.