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 ~~August,~~September 2025

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 ~~Pillar~~press 3release ~~filing~~announcing senior leadership appointments of The Bank of N.T. Butterfield & Son Limited ~~for the six-month period ended June 30, 2025~~.

SIGNATURES

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.

Date: August 29, 2025	THE BANK OF N.T. BUTTERFIELD & SON LIMITED
Date: September 2, 2025	THE BANK OF N.T. BUTTERFIELD & SON LIMITED
	By:	/s/ ~~Craig~~Michael ~~Bridgewater~~Schrum
	Name:	~~Craig~~Michael ~~Bridgewater~~Schrum
	Title:	President and Group Chief Financial Officer


2

EXHIBIT INDEX

Exhibit						Description
99.1						~~Pillar~~Butterfield 3Announces ~~filing~~Senior -Leadership ~~June 30, 2025~~Appointments


3

Filing Compare · Bank of N.T. Butterfield & Son Ltd