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): ~~October~~May 1713, ~~2025~~2026

NSTAR ELECTRIC COMPANY

(Exact name of registrant as specified in its charter)

Massachusetts

1-02301

04-1278810

(State or other jurisdiction

of organization)

(Commission File Number)

(I.R.S. Employer

Identification No.)

800 Boylston Street

Boston, Massachusetts

02199

(Address of principal executive offices)

(Zip Code)

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):

Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

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

Title of each class	Trading Symbol(s)	Name of each exchange on which registered
None	None	None

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. ¨

Section 2

Financial Information

Item 2.03

Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant.

On ~~October 17~~May 13, ~~2025~~2026, NSTAR Electric Company, doing business as Eversource Energy (“NSTAR Electric”), issued an$350,000,000 ~~additional~~aggregate principal amount of its 4.650% Debentures due 2031 (the “2031 Debentures”) and $~~300~~350,000,000 aggregate principal amount of its 5.20200% Debentures due ~~2035~~2036 (the “~~2035~~2036 Debentures” and, together with the 2031 Debentures, the “Debentures”) pursuant to an Underwriting Agreement, dated ~~October 15~~May 11, ~~2025~~2026, among NSTAR Electric and ~~BofA~~Goldman ~~Securities, Inc., J.P. Morgan Securities LLC, Morgan Stanley~~ Sachs & Co. LLC, ~~PNC~~Mizuho ~~Capital~~Securities ~~Markets~~USA LLC, ~~RBC~~TD Securities ~~Capital~~(USA) ~~Markets,~~ LLC, ~~and~~ U.S. Bancorp Investments, Inc., asand ~~representatives~~Wells ofFargo ~~the several underwriters named therein. The additional 2035 Debentures are part of the same series of debentures issued by NSTAR Electric on February 26~~Securities, ~~2025. Following the closing of this offering~~LLC, ~~the~~as ~~aggregate~~representatives ~~principal amount~~ of the ~~5.20%~~several ~~Debentures~~underwriters ~~due 2035 outstanding totaled $700,000,000~~named therein.

The ~~2035~~ 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~~ 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 to Bank of Montreal Trust Company), as trustee. NSTAR Electric has registered its ~~2035~~ 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. 333-286362-03).

The ~~2035~~2031 Debentures mature on ~~March 1~~May 15, ~~2035~~2031 and bear interest at 54.20650%, payable semi-annually on each ~~March~~May 15 1 and ~~September 1~~November 15, beginning ~~for~~on ~~the~~November 15, 2026. ~~additional~~The ~~2035~~ 2036 Debentures mature on ~~March~~May 15, 12036 and bear interest at 5.200%, payable semi-annually on each May 15 and November 15, beginning on November 15, 2026.

Section 9

Financial Statements and Exhibits

Item 9.01

Financial Statements and Exhibits.

(d) Exhibits.

Exhibit Number		Description
1.1		Underwriting Agreement, dated ~~October~~May 1511, ~~2025~~2026, among NSTAR Electric Company, doing business as Eversource Energy, and ~~BofA~~Goldman ~~Securities,~~Sachs ~~Inc., J.P. Morgan Securities LLC, Morgan Stanley~~ & Co. LLC, ~~PNC~~Mizuho ~~Capital~~Securities ~~Markets~~USA LLC, ~~RBC~~TD ~~Capital~~Securities ~~Markets,~~(USA) LLC, ~~and~~ U.S. Bancorp Investments, Inc., and Wells Fargo Securities, LLC, as representatives of the several Underwriters named therein.
4.1		Form of 54.20650% Debenture due ~~2035 (incorporated by reference to Exhibit 4~~2031.~~2 to the Current Report on Form 8-K filed on February 26, 2025).~~
4.2		Form of 5.200% Debenture due 2036.
5.1		Legal opinion of Ropes & Gray LLP relating to the validity of the Debentures.
23.1		Consent of Ropes & Gray LLP (included in Exhibit 5.1).
104		Cover Page Interactive Data File (embedded within the Inline XBRL document).

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.

	NSTAR ELECTRIC COMPANY
	(Registrant)
October 17, 2025	By:	/s/ Matthew P. Fallon
May 13, 2026	By:	/s/ Matthew P. Fallon
		Matthew P. Fallon
		Assistant Treasurer-Corporate Finance and Cash Management

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