UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-K (Mark One) ☒ Annual report pursuant to section 13 or 15(d) of the Securities Exchange Act of 1934 for the fiscal year ended December 31, 2023 or ☐ Transition report pursuant to section 13 or 15(d) of the Securities Exchange Act of 1934 for the transition period from ____________ to ____________ Commission file number: 001-32991 WASHINGTON TRUST BANCORP, INC. (Exact name of registrant as specified in its charter) Rhode Island 05- ...