NSTAR Electric Company PFD 4.25% (NSARP) 8-KCreation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): September 25, 2023

NSTAR ELECTRIC COMPANY

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code: (800) 286-5000

Not Applicable

(Former name or former address, if changed since last report.)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

Securities registered pursuant to Section 12(b) of the Act:

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (17 CFR §230.405) or Rule 12b-2 of the Securities Exchange Act of 1934 (17 CFR §240.12b-2).

Emerging growth company ¨

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ¨

On September 25, 2023, NSTAR Electric Company, doing business as Eversource Energy (“NSTAR Electric”), issued $150,000,000 aggregate principal amount of its 5.60% Debentures due 2028 (“Debentures”) pursuant to an Underwriting Agreement, dated September 18, 2023, between NSTAR Electric and BofA Securities, Inc., Goldman Sachs & Co. LLC, PNC Capital Markets LLC, RBC Capital Markets, LLC and TD Securities (USA) LLC, as representatives of the several underwriters named therein. The Debentures were issued under an indenture dated as of September 1, 1988, between NSTAR Electric (formerly Boston Edison Company) and The Bank of New York Mellon Trust Company, N.A., formerly known as The Bank of New York Trust Company, N.A. (as successor to The Bank of New York, as successor to Bank of Montreal Trust Company), as trustee. NSTAR Electric has registered its Debentures with the U.S. Securities and Exchange Commission under the Securities Act of 1933, as amended, pursuant to a Registration Statement on Form S-3 (Commission File No. 333-264278-02).

The Debentures mature on October 1, 2028 and bear interest at 5.60%, payable semi-annually on each April 1 and October 1, commencing on April 1, 2024. Interest on the Debentures will accrue from September 25, 2023 and will be computed on the basis of a 360-day year consisting of twelve 30-day months.

SIGNATURE

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.