Proxy Materials

Northwestern Corporation Virtual Annual Meeting of Stockholders
April 29, 2022
10:00 a.m. Mountain Daylight Time
Location: www.virtualshareholdermeeting.com/NWE2022

The following materials are being provided to stockholders of record as of February 28, 2022:

To vote your proxy or to request a hard copy of our annual meeting documents and voting card, please go to www.proxyvote.com. You will need the control number found on your Notice to access this site.

YOUR VOTE IS IMPORTANT • PLEASE VOTE PROMPTLY