NORTHERN STATES POWER CO /WI/

Q: Jun 30 2026

Q: Mar 31 2026

FY: Dec 31 2025

Q: Sep 30 2025

Q: Jun 30 2025

Q: Mar 31 2025

FY: Dec 31 2024

Q: Sep 30 2024

Q: Jun 30 2024

Q: Mar 31 2024

FY: Dec 31 2023

Q: Sep 30 2023

Q: Jun 30 2023

Q: Mar 31 2023

FY: Dec 31 2022

Q: Sep 30 2022

Q: Jun 30 2022

Q: Mar 31 2022

FY: Dec 31 2021

Q: Sep 30 2021

Results of Operations and Financial Condition

Entry into a Material Definitive Agreement

Results of Operations and Financial Condition

Results of Operations and Financial Condition

Other Events

Results of Operations and Financial Condition

Other Events

Results of Operations and Financial Condition

Other Events

Entry into a Material Definitive Agreement

Results of Operations and Financial Condition

Other Events

Results of Operations and Financial Condition

Results of Operations and Financial Condition

2.02,9.01

8.01,9.01

2.02,9.01

2.02,9.01

8.01

2.02,9.01

Prospectus Supplement for Delayed or Continuous Offering

Free Writing Prospectus

Prospectus Supplement for Primary Offering

Prospectus Supplement for Delayed or Continuous Offering

Prospectus Supplement for Primary Offering

Free Writing Prospectus

Automatic Shelf Registration

Automatic Shelf Registration

Prospectus Supplement for Delayed or Continuous Offering

Free Writing Prospectus

Prospectus Supplement for Primary Offering

Prospectus Supplement for Delayed or Continuous Offering

Prospectus Supplement for Primary Offering

Free Writing Prospectus

Automatic Shelf Registration

Prospectus Supplement for Delayed or Continuous Offering

Prospectus Supplement for Primary Offering

Free Writing Prospectus

Prospectus Supplement for Delayed or Continuous Offering

Prospectus Supplement for Primary Offering

Letter from the SEC

Letter from the SEC

Correspondence with the SEC