Material Event (Form 8-K)

On September 15, 2025, Puget Sound Energy, Inc. ("Puget Sound Energy") consummated its public offering of $500,000,000 principal amount of 5.598% Senior Notes due September 15, 2055 (the "Senior Notes") pursuant to a purchase agreement dated September 8, 2025 (the "Purchase Agreement") with Mizuho Securities USA LLC, MUFG Securities Americas Inc., and RBC Capital Markets, LLC, and each of the other underwriters named in Schedule A thereto (collectively, the "Underwriters"). The Senior Notes were issued under an Indenture dated as of December 1, 1997, as supplemented by a Fifth Supplemental Indenture thereto, dated as of May 23, 2018, between the Company and U.S. Bank National Association, as trustee. Puget Sound Energy intends to use the proceeds from the issuance of the Senior Notes to pay down its outstanding commercial paper, if any, fund capital expenditures and for general corporate purposes.

The Senior Notes were registered pursuant to a registration statement (Registration No. 333-289101)on Form S-3under the Securities Act of 1933 that Puget Sound Energy filed and which became effective upon filing with the U.S. Securities and Exchange Commission (the "Commission") on July 30, 2025 (the "Registration Statement"). The Registration Statement was supplemented by a Prospectus Supplement setting forth the terms of the Senior Notes that Puget Sound Energy filed with the Commission on September 8, 2025.

Initially, the Senior Notes will be secured by a series of Puget Sound Energy's electric utility first mortgage bonds, referred to as "Pledged First Mortgage Bonds," which are secured by the Company's electric utility property. The Pledged First Mortgage Bonds were issued under the Company's First Mortgage, dated as of June 2, 1924, as supplemented by a Ninety-Second Supplemental Indenture thereto, dated as of May 1, 2013, between the Company and U.S. Bank National Association, as trustee.

The foregoing description of the Purchase Agreement is qualified in its entirety by reference to the Purchase Agreement, a copy of which is filed as Exhibit 1.1 to this Report.

Perkins Coie LLP, counsel to Puget Sound Energy, has issued an opinion, dated September 15, 2025, regarding the legality of the Senior Notes. A copy of the opinion as to legality is filed as Exhibit 5.1 hereto.