Item 1.01 Entry Into a Material Definitive Agreement On August 11, 2026, Narragansett Bancorp, Inc., a Maryland corporation (the “ Company”), Narragansett Financial Corporation, a Massachusetts-chartered mutual holding company (the “ MHC”), and BayCoast Bank (the “ Bank,” and together with the Company and the MHC, the “ Narragansett Parties”) entered into an Agency Agreement with Piper Sandler & Co. (“ Piper Sandler”). Piper Sandler will assist in the marketing of the Company’s common stock during the Company’s stock offering in connection with the Bank’s and the MHC’s two-tierholding company reorganization. For its marketing agent services, Piper Sandler will receive a fee of (a) 1.35% of the aggregate dollar amount of shares sold in the subscription offering, plus(b) 3.00% of the aggregate dollar amount of shares sold in the community offering, excluding shares purchased by or on behalf of (i) any employee benefit plan or trust of the Narragansett Parties established for the benefit of its directors, trustees, officers and employees, (ii) any director, officer or employee of the Narragansett Parties or members of their immediate families (whether directly or through a personal trust), and (iii) a charitable foundation the Company is establishing in connection with the reorganization. In the event shares of common stock are sold in a syndicated offering, Piper Sandler will receive fees of 5.00% of the aggregate dollar amount of shares of common stock sold in the syndicated offering to Piper Sandler and any other broker-dealers included in the syndicated offering. All fees payable with respect to a syndicated offering will be in addition to fees payable with respect to the subscription and community offerings. Piper Sandler also will be reimbursed for reasonable out-of-pocket accountableexpenses not to exceed $140,000, including fees and expenses of its counsel. In addition, Piper Sandler will receive a fee of $75,000 for records agent management services. Piper Sandler also will be reimbursed for reasonable out-of-pocket accountableexpenses not to exceed $35,000 without prior approval. The shares of common stock are being offered pursuant to a Registration Statement on FormS-1, as amended (RegistrationNo. 333-296731), filed by the Company under the Securities Act of 1933, as amended, and a related prospectus dated August 11, 2026.

Item 9.01 Financial Statements and Exhibits (d)  Exhibits Exhibit Description 1.1 Agency Agreement dated August 11, 2026, by and among Narragansett Bancorp, Inc., Narragansett Financial Corporation, BayCoast Bank and Piper Sandler & Co. (exhibits omitted) ────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── 104.1 The cover page for this Current Report on Form 8-K, formatted in Inline XBRL 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, hereunto duly authorized. NARRAGANSETT BANCORP, INC. DATE: August 17, 2026 By: /s/ Marie Pellegrino Marie Pellegrino President