NSTAR Electric sells $700M in new debentures

NSTAR Electric Company, doing business as Eversource Energy, issued two new series of unsecured debentures totaling $700,000,000.

Rhea-AI Filing Summary

NSTAR Electric Company, doing business as Eversource Energy, issued two new series of unsecured debentures totaling $700,000,000. The company sold $350,000,000 of 4.650% Debentures due 2031 and $350,000,000 of 5.200% Debentures due 2036 under an existing indenture.

Both series pay interest semi-annually each May 15 and November 15, starting on November 15, 2026. The debt was issued pursuant to an Underwriting Agreement with a syndicate led by Goldman Sachs & Co. LLC and others, and was registered on a shelf Registration Statement on Form S-3.

Insights

Utility credit and capital structure analyst

NSTAR Electric adds $700M of fixed-rate debt maturing in 2031 and 2036.

NSTAR Electric issued two tranches of debentures: $350,000,000 at 4.650% due 2031 and $350,000,000 at 5.200% due 2036. These are long-dated, fixed-rate obligations under an existing 1988 indenture.

Fixed coupons lock in current borrowing costs through 2031 and 2036, which can help planning for a capital-intensive utility. Actual balance sheet impact depends on how proceeds are used, which is not detailed in the excerpt, and on future rate recovery decisions by regulators.

The debentures were sold through a large underwriting syndicate and registered on Form S-3, indicating a standardized, investment-grade style transaction. Future filings and regulatory materials may clarify how this new debt ties into capital spending, refinancing, or general corporate purposes.

8-K Event Classification

2 items: 2.03, 9.01

2 items

Item 2.03 Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement Financial

The company incurred a new significant debt or off-balance-sheet obligation.

Item 9.01 Financial Statements and Exhibits Exhibits

Financial statements, pro forma financial information, or exhibit attachments filed with this report.

Key Figures

Total debentures issued: $700,000,000 aggregate principal amount 2031 Debentures size: $350,000,000 principal amount 2031 coupon rate: 4.650% +4 more

7 metrics

Total debentures issued $700,000,000 aggregate principal amount 2031 and 2036 Debentures issued May 13, 2026

2031 Debentures size $350,000,000 principal amount 4.650% Debentures due May 15, 2031

2031 coupon rate 4.650% Interest rate on Debentures due 2031

2036 Debentures size $350,000,000 principal amount 5.200% Debentures due May 15, 2036

2036 coupon rate 5.200% Interest rate on Debentures due 2036

Interest payment dates May 15 and November 15 Semi-annual payments starting November 15, 2026

Registration form Form S-3 (File No. 333-286362-03) Shelf registration for debentures

Key Terms

Debentures, Underwriting Agreement, indenture, Registration Statement on Form S-3, +1 more

5 terms

Debentures financial

"issued $350,000,000 aggregate principal amount of its 4.650% Debentures due 2031 and $350,000,000 aggregate principal amount of its 5.200% Debentures due 2036"

A debenture is a company’s long-term IOU sold to investors that promises regular interest payments and repayment of principal at a set date; unlike equity, it represents debt rather than ownership. Think of it like lending money to a business in exchange for a fixed stream of payments, so investors watch a debenture’s interest rate and the borrower’s financial health to judge income reliability and risk of not being repaid.

Underwriting Agreement financial

"pursuant to an Underwriting Agreement, dated May 11, 2026, among NSTAR Electric and Goldman Sachs & Co. LLC, Mizuho Securities USA LLC, TD Securities (USA) LLC, U.S. Bancorp Investments, Inc., and Wells Fargo Securities, LLC"

An underwriting agreement is a contract where a company selling new stocks or bonds hires financial firms to buy those securities and resell them to investors. It matters because the agreement sets the offering price, number of securities, fees and which party bears the risk if sales fall short—think of it as a promise that the sale will happen and a roadmap investors can use to understand how the new securities reach the market.

indenture financial

"The Debentures were issued under an indenture dated as of September 1, 1988, between NSTAR Electric and The Bank of New York Mellon Trust Company, N.A."

An indenture is a legal agreement between a company that borrows money by issuing bonds and the people who buy those bonds. It explains the rules the company must follow, like paying back the money and keeping certain financial promises. This document helps both sides understand their rights and responsibilities.

Registration Statement on Form S-3 regulatory

"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"

A registration statement on Form S‑3 is a short, standardized filing a qualified public company uses to register new securities with regulators so they can be sold to investors; think of it as a pre-approved, reusable permission slip that speeds up future offerings. It matters to investors because it lets the company raise money more quickly and cheaply — which can fund growth or pay debt — but may also lead to share dilution or change in ownership, so it affects value and liquidity.

aggregate principal amount financial

"issued $350,000,000 aggregate principal amount of its 4.650% Debentures due 2031 and $350,000,000 aggregate principal amount of its 5.200% Debentures due 2036"

The aggregate principal amount is the total amount of money borrowed through a bond or loan that the borrower promises to repay. It’s like the original price tag on a loan or bond, showing how much money is involved in the deal. This number matters because it indicates the size of the debt and helps investors understand the scale of the borrowing.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What new debt did NSTAR Electric (NSARO) issue in May 2026?

NSTAR Electric issued two series of debentures totaling $700 million. One tranche is $350 million of 4.650% Debentures due 2031, and the other is $350 million of 5.200% Debentures due 2036, sold under an underwriting agreement.

What are the interest rates and maturities of NSTAR Electric’s new debentures?

The 2031 Debentures carry a fixed 4.650% coupon and mature on May 15, 2031. The 2036 Debentures carry a fixed 5.200% coupon and mature on May 15, 2036, providing long-term fixed-rate financing.

When will NSTAR Electric start paying interest on the new debentures?

Interest on both NSTAR Electric debenture series is payable semi-annually each May 15 and November 15. Payments begin on November 15, 2026, giving investors regular fixed income from that date forward.

Under what regulatory framework were NSTAR Electric’s debentures issued?

NSTAR Electric registered the debentures with the SEC under the Securities Act of 1933. The issuance uses a shelf Registration Statement on Form S-3, allowing standardized offerings under a pre-approved framework and an existing indenture from 1988.

Who underwrote NSTAR Electric’s May 2026 debenture offering?

The debentures were issued under an Underwriting Agreement dated May 11, 2026. Representatives included Goldman Sachs & Co. LLC, Mizuho Securities USA LLC, TD Securities (USA) LLC, U.S. Bancorp Investments, Inc., and Wells Fargo Securities, LLC, among other underwriters.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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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): May 13, 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 May 13, 2026, NSTAR Electric Company, doing business as Eversource Energy (“NSTAR Electric”), issued $350,000,000 aggregate principal amount of its 4.650% Debentures due 2031 (the “2031 Debentures”) and $350,000,000 aggregate principal amount of its 5.200% Debentures due 2036 (the “2036 Debentures” and, together with the 2031 Debentures, the “Debentures”) pursuant to an Underwriting Agreement, dated May 11, 2026, among NSTAR Electric and Goldman Sachs & Co. LLC, Mizuho Securities USA LLC, TD Securities (USA) LLC, U.S. Bancorp Investments, Inc., and Wells Fargo Securities, 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. 333-286362-03).

The 2031 Debentures mature on May 15, 2031 and bear interest at 4.650%, payable semi-annually on each May 15 and November 15, beginning on November 15, 2026. The 2036 Debentures mature on May 15, 2036 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 May 11, 2026, among NSTAR Electric Company, doing business as Eversource Energy, and Goldman Sachs & Co. LLC, Mizuho Securities USA LLC, TD Securities (USA) LLC, U.S. Bancorp Investments, Inc., and Wells Fargo Securities, LLC, as representatives of the several Underwriters named therein.
4.1		Form of 4.650% Debenture due 2031.
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)
May 13, 2026	By:	/s/ Matthew P. Fallon
		Matthew P. Fallon
		Assistant Treasurer-Corporate Finance and Cash Management

Filing Exhibits & Attachments

7 documents

Other Documents

• EX-1.1 EXHIBIT 1.1 171.9 KB
• EX-4.1 EXHIBIT 4.1 46.9 KB
• EX-4.2 EXHIBIT 4.2 45.6 KB
• EX-5.1 EXHIBIT 5.1 9.6 KB
• EX-101 XBRL TAXONOMY EXTENSION SCHEMA 2.9 KB
• EX-101 XBRL TAXONOMY EXTENSION LABEL LINKBASE 33.4 KB
• EX-101 XBRL TAXONOMY EXTENSION PRESENTATION LINKBASE 21.8 KB