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

September 13 4, ~~2023~~2025

Date of Report (Date of earliest event reported)

Exact name of registrant as specified in its charter

~~Exact name of registrant as specified in its charter~~

State or other jurisdiction of incorporation or organization

~~State or other jurisdiction of incorporation or organization~~

Commission

Address of principal executive offices

IRS Employer

~~Address of principal executive offices~~

~~IRS Employer~~

File Number

Registrant's telephone number, including area code

Identification No.

~~Registrant's telephone number, including area code~~

~~Identification No.~~

000-00508

SIERRA PACIFIC POWER COMPANY

88-0044418

~~SIERRA PACIFIC POWER COMPANY~~

~~88-0044418~~

(A Nevada Corporation)

~~(A Nevada Corporation)~~

6100 Neil Road

~~6100 Neil Road~~

Reno, Nevada 89511

~~Reno, Nevada 89511~~

775-834-4011

~~775-834-4011~~

N/A

~~N/A~~

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

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

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing ~~obligations~~obligation of the ~~registrants~~registrant under any of the following provisions:

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

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

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

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

Registrant	Securities registered pursuant to Section 12(b) of the Act:
SIERRA PACIFIC POWER COMPANY	None

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

Emerging growth company o ¨

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. o¨

Item 28.0301. ~~Creation~~ ofOther ~~a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant~~Events.

On September 15 8, ~~2023~~2025, Sierra Pacific Power Company (the “Company”), completed the sale of $~~400~~ 450 million in aggregate principal amount of its 56.~~900~~200% ~~General~~Fixed-to-Fixed ~~and~~Reset ~~Refunding~~Rate ~~Mortgage~~Junior Subordinated Notes, SPPC ~~Series~~JSN ~~2023A~~Series 2025A, due ~~2054~~2055 (the "“Notes"”) pursuant to aan ~~Purchase~~Underwriting Agreement, dated September 13 4, ~~2023~~2025, between the Company and ~~representatives~~the ofunderwriters named therein (the ~~purchasers~~“Underwriters”). The ~~sale~~Underwriting ~~was~~Agreement ~~exempt~~contains ~~from~~certain customary representations, warranties and covenants concerning the Company and the registration ~~requirements~~statement relating to the offering of the Notes. In addition, the Company has agreed to indemnify the Underwriters against certain liabilities, including liabilities under the Securities Act of 1933, as amended, and the Securities Exchange Act of 1934, as amended.

The ~~Company will pay interest on the~~ Notes ~~semi-annually in arrears on March 15 and September 15 of each year, beginning on March 15, 2024. The Notes~~ were issued ~~under~~pursuant ~~and~~to ~~secured~~an ~~by the General and Refunding Mortgage Indenture~~indenture, ~~dated~~by ~~as of May 1, 2001, as amended~~ and ~~supplemented (the “G&R Indenture”),~~ between the Company and The Bank of New York Mellon Trust Company, N.A., as Trustee., ~~The~~dated ~~Notes~~September 8, ~~will~~2025 ~~mature~~(the on“Base ~~March 15~~Indenture”), as ~~2054.~~supplemented ~~The~~by ~~Company~~a ~~intends~~first tosupplemental ~~use~~indenture, ~~the~~dated ~~net~~September 8, ~~proceeds~~2025 to(the ~~fund~~“First ~~capital~~Supplemental ~~expenditures~~Indenture” and, ~~for~~together with ~~general~~the ~~corporate~~Base ~~purposes.~~Indenture, Wethe ~~will~~“Indenture”). ~~initially~~The ~~use~~Company aintends ~~portion~~to ofuse the net proceeds tofrom ~~repay short-term borrowings incurred under~~ the ~~Company's~~sale ~~revolving credit facility in connection with the redemption in August 2023~~ of the ~~Company’s~~Notes ~~3.375%~~to ~~General~~fund capital expenditures and ~~Refunding~~for ~~Mortgage~~general ~~Notes,~~corporate ~~Series T, due 2023~~purposes.

AtThe ~~any~~Notes ~~time~~will ~~prior~~bear tointerest ~~September~~(i) from 15and including September 8, ~~2053~~2025 (the “~~Par~~Original ~~Call~~Issue Date”) to, ~~the~~but ~~Company~~excluding, ~~may~~December 15, ~~redeem~~2030 (the ~~Notes~~“First Reset Date”) at ~~its~~the ~~option,~~rate inof ~~whole~~6.200% orper inannum ~~part,~~and at(ii) from ~~any time~~ and ~~from~~including ~~time~~the toFirst ~~time~~Reset Date, atduring aeach ~~redemption~~Reset ~~price~~Period ~~equal~~(as todefined in the ~~greater of (1~~Indenture) at (a) ~~the~~rate ~~sum~~per ofannum ~~the~~equal ~~present~~to ~~values of~~ the ~~remaining~~Five-year ~~scheduled~~U.S. ~~payments~~Treasury ofRate ~~principal~~(as ~~and~~defined ~~interest~~in ~~thereon discounted to~~ the ~~redemption~~Indenture) ~~date~~as ~~(assuming~~of the ~~Notes~~most ~~matured~~recent onReset ~~the~~Interest ~~Par Call~~ Determination Date) on(as adefined ~~semi-annual~~in ~~basis~~the ~~(assuming~~Indenture) plus a ~~360-day~~spread ~~year consisting~~ of ~~twelve~~2.549%, ~~30-day~~to ~~months)~~be atreset ~~the~~on ~~Treasury~~each ~~Rate~~Reset ~~plus~~Date ~~25 basis points less~~ (b)as ~~interest~~defined ~~accrued~~in to the ~~date of redemption~~Indenture), and ~~(2)~~will ~~100%~~mature on ofDecember 15, ~~the~~2055. ~~principal~~Interest ~~amount~~on of the Notes towill be ~~redeemed,~~payable ~~plus,~~semi-annually in ~~either~~arrears ~~case,~~on ~~accrued~~June 15 and ~~unpaid~~December 15 ~~interest~~of ~~thereon~~each year, tobeginning ~~the~~on ~~redemption~~December 15, ~~date~~2025.

OnThe Company may redeem some or all of the Notes, at its option, in whole or in part (i) on any day in the period commencing on the date falling 90 days prior to the First Reset Date and ending on and including the First Reset Date and (ii) after the ~~Par~~First ~~Call~~Reset Date, on any interest payment date, at a redemption price in cash equal to 100% of the principal amount of the Notes being redeemed, plus, subject to the terms of the Indenture, accrued and unpaid interest on the Notes to be redeemed to, but excluding, the redemption date. The Company also may at its option redeem the Notes, in whole orbut not in part, (a) for a period of 120 days following the occurrence of a Tax Event (as defined in the Indenture) at ~~any~~a ~~time~~redemption price in cash equal to 100% of the principal amount of the Notes, plus, subject to the terms of the Indenture, accrued and ~~from~~unpaid ~~time~~interest on the Notes to, ~~time~~but excluding, the redemption date, and (b) for a period of 120 days following the occurrence of a Rating Agency Event (as defined in the Indenture) at a redemption price in cash equal to ~~100~~102% of the principal amount of the Notes, plus, ~~being~~subject ~~redeemed,~~to ~~plus~~the terms described in the Indenture, accrued and unpaid interest ~~thereon~~on the Notes to, but excluding, the redemption date.

The Notes ~~are~~will ~~subject~~be tounsecured ~~the~~obligations ~~terms~~ and ~~conditions~~will ofrank ~~the~~junior ~~G&R Indenture, including without limitation the provisions relating to “Events of Default”~~ and ~~the~~subordinate in ~~acceleration~~right of ~~the~~payment ~~Notes~~to ~~upon~~ the ~~occurrence~~prior ofpayment anin ~~Event~~full of ~~Default.~~the ~~Events~~Company’s ofexisting ~~Default~~and ~~are~~future ~~generally~~Senior ~~any~~Debt ~~of the following events:~~ (i)as ~~failure~~defined toin ~~pay interest on any security outstanding under~~ the ~~G&R~~ Indenture ~~within~~). The 60Notes ~~days,~~will orrank ~~principal~~equally ofin orright ~~premium~~of ~~on any such security within three business days, after such~~ payment iswith ~~due; (ii) failure to perform, or breach of,~~ any ~~covenant,~~future ~~agreement~~unsecured orindebtedness ~~warranty~~that of the Company ~~contained~~may inincur ~~the~~from ~~G&R~~time ~~Indenture which continues for 90 days after written notice thereof is given~~ to ~~the~~time ~~Company by~~ if the ~~Trustee~~terms ~~or to the Company and the Trustee by the holders~~ of atsuch ~~least~~indebtedness ~~thirty-three~~provide ~~percentum~~that ~~(33%)~~it inranks ~~principal~~equally ~~amount~~with of the ~~securities~~Notes ~~outstanding~~in ~~under~~right ~~the G&R Indenture; or (iii) certain events relating to the reorganization, bankruptcy or insolvency~~ of ~~the Company or appointment of a receiver or trustee for the Company’s property~~payment.

InThe ~~connection~~foregoing ~~with~~descriptions ~~the sale~~ of the ~~Notes,~~Underwriting ~~the Company entered into a registration rights agreement, dated as of September 15, 2023 (the “Registration Rights~~ Agreement”), ~~with~~ the ~~representatives~~Base Indenture ofand the ~~initial~~First ~~purchasers~~Supplemental ofIndenture ~~the~~do ~~Notes,~~not ~~pursuant~~purport to ~~which~~be ~~the~~complete ~~Company agreed to register with the Securities~~ and ~~Exchange~~are ~~Commission,~~qualified noin ~~later~~their ~~than~~entirety ~~September~~by ~~13,~~reference ~~2024, an offer~~ to ~~exchange~~ the ~~Notes~~full text ~~for~~of ~~exchange~~the ~~notes~~Underwriting ~~that~~Agreement, ~~will be issued under~~ the ~~G&R~~Base Indenture ~~in the same aggregate principal amount as~~ and ~~with terms that will be substantially identical to~~ the ~~Notes. If~~First ~~the~~Supplemental ~~Company~~Indenture, ~~fails~~copies toof ~~satisfy~~which ~~its~~are ~~registration~~filed ~~obligations~~ as ~~required~~Exhibits ~~by the Registration Rights Agreement~~1.1, ~~the Company may be required to pay additional interest at a rate of 0~~ 4.~~25%~~1 ~~per annum for a 90-day period,~~ and 04.~~50% thereafter~~2, ~~until the failure is cured~~respectively, uphereto toand aare ~~maximum~~incorporated ~~period~~by ofreference ~~two years~~herein.

The foregoing discussion of the Notes and the Registration Rights Agreement is a summary and is qualified in its entirety by reference to the Officer’s Certificate establishing the terms of the Notes under the G&R Indenture and the Registration Rights Agreement, copies of which are filed as Exhibit 4.1 and 4.2, respectively, to this Form 8-K.

Item 8.01. Other Events

On June 3, 2022, the Company filed a Current Report on Form 8-K (the “June 2022 Form 8-K”) reporting the sale of $250 million in aggregate principal amount of its 4.71% General and Refunding Mortgage Bonds, Series W, due 2052 (the “Series W Bonds”).

The June 2022 Form 8-K incorrectly summarizes the Events of Default under the G&R Indenture. The Events of Default under the G&R Indenture, which were not modified by the Third Supplemental Indenture, dated as of May 31, 2022, and apply to all series of securities issued under the G&R Indenture, including the Series W Bonds and the Notes, are generally any of the following events: (i) failure to pay interest on any security outstanding under the G&R Indenture within 60 days, or principal of or premium on any such security within three business days, after such payment is due; (ii) failure to perform, or breach of, any covenant, agreement or warranty of the Company contained in the G&R Indenture which continues for 90 days after written notice thereof is given to the Company by the Trustee or to the Company and the Trustee by the holders of at least thirty-three percentum (33%) in principal amount of the securities outstanding under the G&R Indenture; or (iii) certain events relating to the reorganization, bankruptcy or insolvency of the Company or appointment of a receiver or trustee for the Company’s property.

The foregoing discussion of the Events of Default is qualified in its entirety by reference to (i) the G&R Indenture previously filed with the U.S. Securities and Exchange Commission and (ii) the Third Supplemental Indenture, a copy of which is filed as Exhibit 4.3 to this Form 8-K.

The information in this Item 8.01 amends and replaces the incorrect information in the June 2022 Form 8-K.

Item 9.01.

Financial Statements and Exhibits.

(d) Exhibits

Exhibit No.	Description	~~Description~~
4.1		Officer’s Certificate establishing the terms of Sierra Pacific Power Company’s 5.900% General and Refunding Mortgage Bonds, SPPC Series 2023A, due 2054.
1.1	Underwriting Agreement, dated September 4, 2025, between Sierra Pacific Power Company and the underwriters named therein.
4.2		Registration Rights Agreement dated September 15, 2023 by and among Sierra Pacific Power Company and BofA Securities, Inc., J.P. Morgan Securities LLC, Mizuho Securities USA LLC, RBC Capital Markets, LLC, and Truist Securities, Inc. as representatives of the several Purchasers listed therein.
4.1	Indenture, dated as of September 8, 2025, by and between Sierra Pacific Power Company and The Bank of New York Mellon Trust Company, N.A., as trustee, relating to the 6.200% Fixed-to-Fixed Reset Rate Junior Subordinated Notes, SPPC JSN Series 2025A, due 2055.
4.3		Third Supplemental Indenture, dated as of May 31, 2022, by and between Sierra Pacific Power Company and the Bank of New York Mellon Trust Company, N.A., as Trustee.
4.2	First Supplemental Indenture, dated as of September 8, 2025, by and between Sierra Pacific Power Company and The Bank of New York Mellon Trust Company, N.A., as trustee, relating to the 6.200% Fixed-to-Fixed Reset Rate Junior Subordinated Notes, SPPC JSN Series 2025A, due 2055.
104		Cover Page Interactive Data File (embedded within the Inline XBRL document).
5.1	Opinion of ArentFox Schiff LLP.
5.2	Opinion of Hutchison & Steffen, PLLC.
104	Cover Page Interactive Data File (embedded within the Inline XBRL document).

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.

	SIERRA PACIFIC POWER COMPANY	~~SIERRA PACIFIC POWER COMPANY~~
Date: September 18, 2023
Date: September 10, 2025
	/s/ Michael J. Behrens	~~/s/ Michael J. Behrens~~
	Michael J. Behrens	~~Michael J. Behrens~~
	Vice President and Chief Financial Officer	~~Vice President and Chief Financial Officer~~

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