6-K

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER

PURSUANT TO RULE 13A-16 OR 15D-16

UNDER THE SECURITIES EXCHANGE ACT OF 1934

For the month of September, 2020

Commission File Number: 001-37877

The Bank of N.T. Butterfield & Son Limited

(Translation of registrant’s name into English)

65 Front Street

Hamilton, HM 12

Bermuda

(Address of principal executive offices)

Indicate by check mark whether the registrant files or will file annual reports under cover Form 20-F or Form 40-F.

Form 20-F ý Form 40-F o

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(1): o

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(7): o

DOCUMENTS INCLUDED AS PART OF THIS FORM 6-K

Attached hereto as Exhibit 99.1 is the Financial Report for the Six Months Ended June 30, 2020 of The Bank of N.T. Butterfield & Son Limited.

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

EXHIBIT INDEX

bntbhalfyearreport2020

FINANCIAL REPORT FOR THE SIX MONTHS ENDED JUNE 30, 2020 THE BANK OF N.T. BUTTERFIELD & SON LIMITED

Report to shareholders & financial highlights Six months ended June 30, 2020 As a leading, independent offshore bank and trust company, In September, the Bank made a number of senior Butterfield continues to build long-term value for our management changes focused on managing risk, enhancing shareholders through strong client relationships and the the Butterfield brand, driving Trust profitability and developing provision of exceptional service. Despite the challenges our people. Sabeth Siddique, Group Chief Risk Officer; presented by the COVID-19 pandemic, the Bank recorded Bri Hidalgo, Group Head of Compliance and Operational solid earnings for the first half of 2020. Risk; and Kevin Dallas, Group Head of Marketing and Communications join Butterfield as members of the Bank’s In response to the global pandemic and as an essential service Executive Committee. Jane Pearce, who was appointed provider, Butterfield continued to serve our clients during Group Head of Trust in February 2020, has also joined the temporary government-mandated closures in our home Executive Committee. markets, providing services both in person and electronically. The Bank shifted rapidly to a remote working model with no Capital Management interruption in operations, while keeping Banking Centers The common equity tier 1 capital ratio and total capital ratios in Bermuda and Cayman open to help ensure Government were 17.0% and 21.2%, respectively, compared to 17.3% and relief payments could be processed and funds continued to 19.4% at year-end 2019. circulate in our local economies. Butterfield also offered relief to borrowers in Bermuda and Cayman through temporary Dividends totalling $0.88 per share ($0.44 in each of Q1 loan deferrals, and significantly increased contributions to and Q2) have been paid to shareholders with respect to the community-based support programs. six months ended June 30, 2020, and a total of 2.5 million common shares were repurchased during the first two quarters Net income for the period ended June 30, 2020 decreased by of 2020 under the Bank’s common share repurchase plan. 17.8% to $74.6 million from $90.7 million for the comparative six-month period ended June 30, 2019. The core return on During the second quarter, the Bank issued $100 million of average tangible common equity* for the period was 17.0%, 5.25% 10-year, fixed to floating rate subordinated debt. The compared to 25.1% for the same period last year. proceeds of the issuance will be used primarily to replace existing debt. Non-interest income increased by 1.8% from $87.6 million for the six-month period ended June 30, 2019 to $89.2 million As we prepare for an extended period of low interest rates for the period ended June 30, 2020 due to higher foreign and a changing economic landscape, and the heightened exchange, asset management, and custody revenues, offset by risks those factors present for our loan portfolio, we will a decline in Trust and banking fee revenues associated largely continue to exercise diligence in the management of credit with the pandemic. and operational risk, and expenses. We anticipate a greater emphasis on our stable fee businesses and restructuring Net interest income before provision for credit losses for the certain aspects of our business operations to realize first six months of 2020 decreased by 3.7% to $166.7 million efficiency improvements. as compared to $173.1 million for the first half of 2019, due to lower yields on investments from reduced interest rates, offset I am proud of the way Butterfield responded to the COVID-19 by higher loan interest income resulting from the onboarding pandemic, and with the changes we are making to adjust to of business from the ABN AMRO Channel Islands business in the new economic realities, the Bank will continue to be well the second half of 2019. The net interest margin decreased to positioned for profitability and growth, with a strong balance 2.56% for the six months ended June 30, 2020, compared to sheet and capital ratios. 3.24% for the same period last year. Board and Management Changes In April, independent directors Caroline Foulger and Meroe Park retired from the Board and Group Chief Financial Officer, Michael W. Collins Michael Schrum, joined the Board as an executive director. Chairman and Chief Executive Officer In August, we welcomed new independent directors Leslie Godridge and Jana Schreuder to the Board. *See table “Reconciliation of US GAAP Results to Core Earnings” for reconciliation of US GAAP results to non-GAAP measures.

Group highlights (Results for six months ended June 30, 2020 with comparisons to the period ended June 30, 2019) Net income decreased by 17.8% from $90.7 million for the Provisions for credit losses increased from a recovery of six-month period ended June 30, 2019 to $74.6 million for the $1.0 million to a provision of $9.5 million due primarily to the period ended June 30, 2020. adoption of the new Current Expected Credit Losses standard effective January 1, 2020, which is driving the reserve build Non-interest income increased by 1.8% from $87.6 million through lifetime losses, past and current conditions, as well at June 30, 2019 to $89.2 million at June 30, 2020. Foreign as reasonable and supportable forecasts. exchange income rose 10.2% to $18.9 million driven by higher volumes due to both the ABN AMRO acquisition and market Net interest margin (NIM) for the six months ended June dislocation as a result of the COVID-19 pandemic. Asset 30, 2020 was 2.56% compared to 3.24% in the comparative management revenues increased by 11.7% to $15.2 million period in the prior year. The decrease was due mainly to the and Custody and other administration services revenues rose impact of lower market rates across the yield curve, which 19.5% to $6.9 million, both primarily as a result of the ABN was partially offset by lower deposits costs. AMRO acquisition. Trust revenues decreased 4.2% to $24.5 million, driven principally by lower activity-based Other gains (losses) for the six months ended June 30, 2020 revenues due to the COVID-19 pandemic, and lower fixed fees was a gain of $0.1 million compared to a gain of $1.9 million due to the strategic exit of certain customer relationships. for the comparative period ended June 30, 2019. This is due Banking fee revenues decreased 12.3% to $20.4 million, due mainly to mark-to-market gains on equity securities and primarily to much lower economic activity resulting from the sale of available-for-sale (AFS) investments during the COVID-19-related “shelter-in-place” government mandates comparable period in 2019. across all of Butterfield’s operating jurisdictions, primarily during the months of April and May. Other non-interest Salaries and other employee benefits (including non- income increased by 46.5% to $3.5 million due to increased service employee benefits expense) decreased by 9.3% to rental income from the subletting of property in the Channel $86.1 million due primarily to salaries and other employee Islands, as well as higher unclaimed assets. benefits relating to the closure of a bank branch in Bermuda, a voluntary early retirement program and the costs Net interest income before provisions for credit losses associated with the departure of a former senior Group decreased by 3.7% from $173.1 million for the six-month executive recognized in 2019. period ended June 30, 2019 to $166.7 million for the period ended June 30, 2020. Total interest income decreased Other non-interest expenses increased by 10% from $8.8 million to $187.7 million due to lower investment and $78.0 million for the six-month period to June 30, 2019 to cash yields driven by reduced interest rates as a result $85.8 million for the period to June 30, 2020 due primarily to of recent reductions in market interest rates which were an increase in technology and communications expenses by partially offset by higher loan interest income as a result of 9.7% to $32.7 million as a result of software and integration the ABN AMRO acquisition in the second half of 2019. Total costs associated with the ABN AMRO acquisition and an interest expense decreased $2.4 million to $21.0 million due increase in property expenses by 30.4% to $14.5 million to both lower term deposit volumes and costs and the impact also as a result of the ABN AMRO acquisition, as well as the of active deposit repricing in the Channel Islands. opening of the new Camana Bay Banking Centre in Grand Cayman in early 2020.

Total assets were $13.2 billion at June 30, 2020, a decrease Total deposits were $11.6 billion at June 30, 2020, a of $0.8 billion from December 31, 2019. The Bank maintained decrease of $0.8 billion from December 31, 2019. This a highly liquid position at June 30, 2020, with $7.7 billion of decrease is mainly a reflection of rate decreases in term cash and demand deposits with banks, reverse repurchase deposit products, lower GBP/USD exchange rates and agreements and liquid investments representing 58.7% of repricing initiatives in the Channel Islands. total assets, compared with 60% at December 31, 2019. Shareholders’ equity increased 2.8% from $963.7 million as Loans, net of allowance for credit losses totaled of December 31, 2019 to $990.3 million as of June 30, 2020, $5.0 billion at June 30, 2020, and had decreased by driven primarily by 2020 net income and the net change $124.7 million compared with December 31, 2019, due in unrealized gains (losses) on AFS investments, offset by primarily to the translation of the Channel Islands and UK the payment of common share dividends, purchase and loans denominated in GBP at lower GBP/USD exchange cancellation of common shares for treasury. rates. The loan portfolio represented 38.2% of total assets at June 30, 2020 (December 31, 2019: 36.9%), while loans Assets under administration were $118.1 billion at as a percentage of total deposits increased from 41.3% June 30, 2020. Assets under management were $5.4 billion at December 31, 2019 to 43.2% at June 30, 2020. The at June 30, 2020. increases in both measures are due principally to a decrease in customer deposits at June 30, 2020 including expected Complete financial statements and notes to the financial declines of Euro deposits held in the Channel Islands as the statements for the six months ended June 30, 2020 are deposit book was repriced following the acquisition of available via the Investor Relations link of our website, ABN AMRO. www.butterfieldgroup.com. Investments held at June 30, 2020 was $4.4 billion, down $82.7 million from December 31, 2019. The investment portfolio is composed of high quality assets with 99.8% invested in A-or-better-rated securities. Total net unrealized gains at June 30, 2020 were $181.9 million, compared with total net unrealized gains of $60.8 million at December 31, 2019, an increase propelled by lower long-term US-dollar interest rates.

Financial highlights In thousands of US dollars except per share data (Unaudited except where stated) As at Consolidated Balance Sheets June 30, 2020 December 31, 2019 (1) Cash due from banks, securities purchased under agreement to resell, and short-term investments 3,364,594 3,910,733 Investment in securities 4,353,720 4,436,423 Loans, net of allowance for credit losses 5,017,874 5,142,622 Premises, equipment and computer software 159,195 158,233 Total assets 13,150,702 13,921,575 Total deposits 11,615,615 12,441,625 Long-term debt (net of debt issuance costs) 241,474 143,500 Shareholders' equity 990,316 963,743 (1) Audited For the three-month period ended For the six-month period ended Consolidated Statements of Operations June 30, 2020 June 30, 2019 June 30, 2020 June 30, 2019 Non-interest income 41,650 44,239 89,220 87,619 Other gains (losses) 684 193 104 1,944 Net interest income after provision for credit losses 74,756 86,080 157,170 174,097 Total net revenue 117,090 130,512 246,494 263,660 Salaries and other employee benefits (2) 41,506 52,101 86,075 94,891 Other non-interest expenses (3) 41,250 39,769 85,808 78,020 Net income 34,334 38,642 74,611 90,749 Non-core items (4) 60 12,491 540 12,105 Core net income (4) 34,394 51,133 75,151 102,854 (2) Includes non-service employee benefits expense (3) Includes income taxes Shareholder data Return on common equity (%) 14.0% 17.1% 15.3% 20.3% Core return on average tangible common equity (%) (4) 15.5% 24.6% 17.0% 25.1% Return on average assets 1.0% 1.4% 1.1% 1.6% Core return on average tangible assets (4) 1.1% 1.8% 1.1% 1.9% Efficiency ratio 66.7% 70.0% 65.4% 65.2% Core efficiency ratio(4) 66.7% 60.3% 65.1% 60.2% Book value per common share (in $) 19.73 17.53 19.73 17.53 Tangible book value per share (in $) (4) 17.94 16.16 17.94 16.16 Earnings per share ($) Basic 0.68 0.73 1.45 1.70 Diluted 0.67 0.72 1.44 1.68 Diluted - core (4) 0.67 0.95 1.45 1.91 Number of common shares (5) 50,203,126 52,987,770 50,203,126 52,987,770 Dividend paid - common (6) 0.44 0.44 0.88 0.88 (4) See table “Reconciliation of US GAAP Results to Core Earnings” for During the six-month period ended June 30, 2020, 272,211 restricted reconciliation of US GAAP results to non-GAAP measures. common shares of the Bank were granted to executive officers and (5) Actual outstanding excludes common shares held as treasury stock. no unrestricted common shares were granted to directors. During (6) Common share capital, BMD 0.01 par, authorised voting ordinary the same period, no stock options were granted by the Bank and no shares 2,000,000,000 and non-voting ordinary shares 6,000,000,000. outstanding stock options were exercised by executive officers or directors. Directors’ and Executive Officers’ Share Interests Pursuant to Regulation 6.9(2)(x)(a) and (b) of Section IIA of the Further Financial Information Bermuda Stock Exchange Listing Regulations, the total interests of all The Group’s results are stated in accordance with US GAAP. directors and executive officers of the Bank as at June 30, 2020 in the Further financial information may be found on our web site at: common shares of the Bank were 598,202 shares. www.butterfieldgroup.com.

Reconciliation of to exclude certain income or expense items that are not representative of our business operations, or “non-core”. US GAAP results to Core net income includes revenue, gains, losses and expense items incurred in the normal course of business. We believe core earnings that expressing earnings and certain other financial measures excluding these non-core items provides a meaningful base for period-to-period comparisons, which management The table below shows the reconciliation of net income in believes will assist investors in analysing the operating results accordance with US GAAP to core earnings, a non-GAAP of the Bank and predicting future performance. We believe measure, which excludes certain significant items that are that presentation of these non-GAAP financial measures will included in our US GAAP results of operations. We focus on permit investors to assess the performance of the Bank on core net income, which we calculate by adjusting net income the same basis as management. For the three-month period ended For the six-month period ended (in millions except per share amounts) June 30, 2020 June 30, 2019 June 30, 2020 June 30, 2019 Net income to common shareholders A 34.3 38.6 74.6 90.7 Non-core items Non-core (gains) losses Gain on disposal of a pass-through note investment (formerly a SIV) — — — (1.0) Total non-core (gains) losses B — — — (1.0) Non-core expenses     Early retirement program, redundancies and other non-core compensation costs 0.1 11.3 0.5 11.3 Business acquisition costs — 1.2 0.1 1.8 Total non-core expenses C 0.1 12.5 0.6 13.1 Total non-core items D=B+C 0.1 12.5 0.6 12.1 Core net income attributable to common shareholders E=A+D 34.4 51.1 75.2 102.9 Average common equity F 985.0 905.7 979.0 900.0 Less: average goodwill and intangible assets (90.5) (73.0) (92.5) (73.9) Average tangible common equity G 894.5 832.7 886.5 826.1 Return on equity A/F 14.0 % 17.1 % 15.3 % 20.3 % Core return on average tangible common equity E/G 15.5 % 24.6 % 17.0 % 25.1 % Core earnings per common share fully diluted       Adjusted weighted average number of diluted common shares (in thousands) H 50,984.5 53,547.1 51,700.2 53,912.9 Earnings per common share fully diluted A/H 0.67 0.72 1.44 1.68 Non-core items per share D/H — 0.23 0.01 0.22 Core earnings per common share fully diluted E/H 0.67 0.95 1.45 1.91 Core return on average tangible assets       Total average assets I 13,202.8 11,294.3 13,522.8 11,177.5 Less: average goodwill and intangible assets   (90.5) (73.0) (92.5) (73.9) Average tangible assets J 13,112.3 11,221.3 13,430.3 11,103.6 Return on average assets A/I 1.0 % 1.4 % 1.1 % 1.6 % Core return on average tangible assets E/J 1.1 % 1.8 % 1.1 % 1.9 % Tangible equity to tangible assets       Shareholders’ equity K 990.3 928.7 990.3 928.7 Less: goodwill and intangible assets   (89.7) (72.2) (89.7) (72.2) Tangible common equity L 900.7 856.5 900.7 856.5 Basic participating shares outstanding (in millions) M 50.2 53.0 50.2 53.0 Book value per common share N=K/M 19.73 17.53 19.73 17.53 Tangible book value per common share O=L/M 17.94 16.16 17.94 16.16 Efficiency ratio       Non-interest expenses   82.0 91.7 170.1 172.6 Less: Amortization of intangibles   (1.4) (1.2) (2.9) (2.5) Non-interest expenses before amortization of intangibles P 80.6 90.5 167.2 170.1 Non-interest income   41.7 44.2 89.2 87.6 Net interest income before provision for credit losses 79.1 85.2 166.7 173.1 Net revenue before provision for credit losses and other gains/losses Q 120.8 129.4 255.9 260.8 Efficiency ratio P/Q 66.7 % 70.0 % 65.4 % 65.2 % Core efficiency ratio       Non-interest expenses   82.0 91.7 170.1 172.6 Less: non-core expenses (C) (0.1) (12.5) (0.6) (13.1) Less: amortization of intangibles   (1.4) (1.2) (2.9) (2.5) Core non-interest expenses before amortization of intangibles R 80.5 78.0 166.7 157.0 Core revenue before other gains and losses and provision for credit losses S 120.8 129.4 255.9 260.8 Core efficiency ratio R/S 66.7 % 60.3 % 65.1 % 60.2 %

FORWARD-LOOKING STATEMENTS This report contains certain forward-looking statements within the meaning of the US Private Securities Litigation Reform Act of 1995. Forward-looking statements include statements with respect to our beliefs, plans, objectives, goals, expectations, anticipations, assumptions estimates, intentions, and future performance, and involve known and unknown risks, uncertainties and other factors, which may be beyond our control, and which may cause the actual results, performance, capital, ownership or achievements of Butterfield to be materially different from future results, performance or achievements expressed or implied by such forward-looking statements due to a variety of factors, including the impact of the COVID-19 pandemic, the scope and duration of the pandemic, actions taken by governmental authorities in response to the pandemic, worldwide economic conditions and fluctuations of interest rates, the successful completion and integration of acquisitions or the realization of the anticipated benefits of such acquisitions in the expected time-frames or at all, success in business retention and obtaining new business and other factors. Forward-looking statements can be identified by words such as "anticipate," "assume," "believe," "estimate," "expect," "indicate," "intend," "may," "plan," "point to," "predict," "project," "seek," "target," "potential," "will," "would," "could," "should," "continue," "contemplate" and other similar expressions, although not all forward-looking statements contain these identifying words. All statements other than statements of historical fact are statements that could be forward-looking statements. All forward-looking statements in this report are expressly qualified in their entirety by this cautionary notice, including, without limitation, those risks and uncertainties described in our SEC reports and filings. Such reports are available upon request from Butterfield, or from the SEC, including through the SEC’s website at https://www.sec.gov. Except as otherwise required by law, Butterfield assumes no obligation and does not undertake to review, update, revise or correct any of the forward-looking statements included in this report, whether as a result of new information, future events or other developments. You are cautioned not to place undue reliance on the forward-looking statements made by Butterfield in this report. Comparisons of results for current and any prior periods are not intended to express any future trends or indications of future performance, and should only be viewed as historical data. The Bank of N.T. Butterfield & Son Limited 65 Front Street Hamilton, Bermuda butterfieldgroup.com