NWE

nwe-202602110001993004false00019930042026-02-112026-02-11

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): February 11, 2026

NorthWestern Energy Group, Inc. (Exact name of registrant as specified in its charter)

Delaware000-5659893-2020320 (State or other jurisdiction of incorporation or organization)(Commission File Number)(I.R.S. Employer Identification No.)

3010 W. 69th StreetSioux FallsSouth Dakota 57108 (Address of principal executive offices) (Zip Code)

Registrant’s telephone number, including area code: 605-978-2900

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:

RegistrantTitle of each classTrading Symbol(s)Name of each exchange on which registered NorthWestern Energy Group, Inc.Common stockNWENasdaq Stock Market LLC

Indicate by check mark whether the registrant is an emerging growth company as defined in 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 ☐ 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. ☐

Item 2.02    Results of Operations and Financial Condition On February 11, 2026, NorthWestern Energy Group, Inc. d/b/a NorthWestern Energy (Nasdaq: NWE) (the “Company”), issued a press release (the “Press Release”) discussing financial results for the year ended December 31, 2025, and announcing earnings guidance for 2026 in the range of $3.68 to $3.83 per diluted share. The Press Release is furnished as Exhibit 99.1 hereto and is incorporated herein by reference. The information in this Current Report on Form 8-K provided under Item 2.02 shall not be deemed “filed” for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or otherwise subject to the liabilities of that Section. The information provided under Item 2.02 in this Current Report shall not be incorporated by reference into any registration statement or other document pursuant to the Securities Act of 1933, as amended, except as shall be expressly set forth by specific reference in such filing. Item 7.01 Regulation FD Disclosure. As previously announced and as stated in the Press Release, the Company will host an investor conference call and webcast on Thursday, February 12, 2026, at 3:30 p.m. Eastern time to review its financial results for the year ending December 31, 2025. During the conference call, Brian Bird, president and chief executive officer, and Crystal Lail, vice president and chief financial officer of the Company, will make a slide presentation (the "Investor Call Presentation") concerning the Company's financial results. The conference call will be webcast live on the Internet at www.northwesternenergy.com/earnings-registration. To participate, please go to the site at least 15 minutes in advance of the webcast to register. An archived webcast will be available shortly after the call and remain active for one year. A copy of the Investor Call Presentation is being furnished pursuant to Regulation FD as Exhibit 99.2 to this Current Report on Form 8-K and is incorporated herein by reference. The information in the presentation shall not be deemed to be “filed” for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or otherwise subject to the liability of that section. Furthermore, the presentation shall not be deemed to be incorporated by reference into the Company's filings under the Securities Act of 1933, as amended, or under the Securities Exchange Act of 1934, as amended, except as set forth with respect thereto in any such filing.

Item 9.01    Financial Statements and Exhibits.

Exhibit No.Description of Document 99.1* Press Release, dated February 11, 2026 99.2* Investor Call Presentation, dated February 12, 2026 104Cover Page Interactive Data File – the cover page XBRL tags are embedded within the Inline XBRL document

* filed herewith

Signatures Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused thi

nwe-202510290001993004false00019930042025-10-292025-10-29

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 29, 2025

NorthWestern Energy Group, Inc. (Exact name of registrant as specified in its charter)

Delaware000-5659893-2020320 (State or other jurisdiction of incorporation or organization)(Commission File Number)(I.R.S. Employer Identification No.)

3010 W. 69th StreetSioux FallsSouth Dakota 57108 (Address of principal executive offices) (Zip Code)

Registrant’s telephone number, including area code: 605-978-2900

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:

RegistrantTitle of each classTrading Symbol(s)Name of each exchange on which registered NorthWestern Energy Group, Inc.Common stockNWENasdaq Stock Market LLC

Indicate by check mark whether the registrant is an emerging growth company as defined in 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 ☐ 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. ☐

Item 2.02    Results of Operations and Financial Condition. On October 29, 2025, NorthWestern Energy Group, Inc. d/b/a NorthWestern Energy (Nasdaq: NWE) (the “Company”) issued a press release (the “Press Release”) discussing financial results for the quarter ended September 30, 2025, and affirming earnings guidance for 2025 in the range of $3.53 to $3.65 per diluted share. The Press Release is furnished as Exhibit 99.1 hereto and is incorporated herein by reference. The information in this Current Report on Form 8-K provided under Item 2.02 shall not be deemed “filed” for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or otherwise subject to the liabilities of that Section. The information provided under Item 2.02 in this Current Report shall not be incorporated by reference into any registration statement or other document pursuant to the Securities Act of 1933, as amended, except as shall be expressly set forth by specific reference in such filing. Item 7.01 Regulation FD Disclosure. As previously announced and as stated in the Press Release, the Company will host an investor conference call and webcast on October 30, 2025, at 3:30 p.m. Eastern time to review its financial results. During the conference call, Brian Bird, president and chief executive officer, and Crystal Lail, vice president and chief financial officer, will make a slide presentation (the "Investor Call Presentation") concerning the Company's financial results. A live webcast of the investor conference call can be accessed from the Company’s website at www.northwesternenergy.com/earnings-registration. To listen and view the slideshow presentation, please go to the site at least 15 minutes in advance of the call to register. An archived webcast will be available shortly after the event and remain active for one year. A copy of the Investor Call Presentation is being furnished pursuant to Regulation FD as Exhibit 99.2 to this Current Report on Form 8-K and is incorporated herein by reference. The information in the presentations shall not be deemed to be “filed” for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or otherwise subject to the liability of that section. Furthermore, the presentations shall not be deemed to be incorporated by reference into the Company's filings under the Securities Act of 1933, as amended, or under the Securities Exchange Act of 1934, as amended, except as set forth with respect thereto in any such filing. Item 9.01    Financial Statements and Exhibits.

Exhibit No.Description of Document 99.1* Press Release, dated October 29, 2025 99.2* Investor Call Presentation, dated October 30, 2025 104Cover Page Interactive Data File – the cover page XBRL tags are embedded within the Inline XBRL document

* filed herewith

Signatures Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this

nwe-202507300001993004false00019930042025-07-302025-07-30

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): July 30, 2025

NorthWestern Energy Group, Inc. (Exact name of registrant as specified in its charter)

Delaware000-5659893-2020320 (State or other jurisdiction of incorporation or organization)(Commission File Number)(I.R.S. Employer Identification No.)

3010 W. 69th StreetSioux FallsSouth Dakota 57108 (Address of principal executive offices) (Zip Code)

Registrant’s telephone number, including area code: 605-978-2900

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:

RegistrantTitle of each classTrading Symbol(s)Name of each exchange on which registered NorthWestern Energy Group, Inc.Common stockNWENasdaq Stock Market LLC

Indicate by check mark whether the registrant is an emerging growth company as defined in 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 ☐ 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. ☐

Item 2.02    Results of Operations and Financial Condition. On July 30, 2025, NorthWestern Energy Group, Inc. d/b/a NorthWestern Energy (Nasdaq: NWE) (the “Company”) issued a press release (the “Press Release”) discussing financial results for the quarter ended June 30, 2025, and announcing earnings guidance for 2025 in the range of $3.53 to $3.65 per diluted share. The Press Release is furnished as Exhibit 99.1 hereto and is incorporated herein by reference. The information in this Current Report on Form 8-K provided under Item 2.02 shall not be deemed “filed” for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or otherwise subject to the liabilities of that Section. The information provided under Item 2.02 in this Current Report shall not be incorporated by reference into any registration statement or other document pursuant to the Securities Act of 1933, as amended, except as shall be expressly set forth by specific reference in such filing. Item 7.01 Regulation FD Disclosure. As previously announced and as stated in the Press Release, the Company will host an investor conference call and webcast on July 31, 2025, at 3:30 p.m. Eastern time to review its financial results. During the conference call, Brian Bird, president and chief executive officer, and Crystal Lail, vice president and chief financial officer, will make a slide presentation (the "Investor Call Presentation") concerning the Company's financial results. A live webcast of the investor conference call can be accessed from the Company’s website at www.northwesternenergy.com/earnings-registration. To listen and view the slideshow presentation, please go to the site at least 15 minutes in advance of the call to register. An archived webcast will be available shortly after the event and remain active for one year. A copy of the Investor Call Presentation is being furnished pursuant to Regulation FD as Exhibit 99.2 to this Current Report on Form 8-K and is incorporated herein by reference. The information in the presentations shall not be deemed to be “filed” for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or otherwise subject to the liability of that section. Furthermore, the presentations shall not be deemed to be incorporated by reference into the Company's filings under the Securities Act of 1933, as amended, or under the Securities Exchange Act of 1934, as amended, except as set forth with respect thereto in any such filing. Item 9.01    Financial Statements and Exhibits.

Exhibit No.Description of Document 99.1* Press Release, dated July 30, 2025 99.2* Investor Call Presentation, dated July 31, 2025 104Cover Page Interactive Data File – the cover page XBRL tags are embedded within the Inline XBRL document

* filed herewith

Signatures Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed