Additional Proxy Soliciting Materials (Form DEFA14A)

NAME & ADDRESS HERE You must use the 11-digit Control Number located in the box to vote via Internet, or to request proxy materials. Important Notice Regarding the Internet Availability of Proxy Materials for the Annual Meeting of Stockholders to be held on June 12, 2026 at 1:00 p.m. Mountain Daylight Time. This communication is not a form of voting and presents only an overview of the more complete proxy materials that are available to you on the Internet. We encourage you to access and review all of the important information contained in the proxy materials before voting. The Proxy Statement and Annual Report are available at https://web.viewproxy.com/AUMN/2026 If you want to receive a paper or email copy of these documents, you must request one by following the instructions on the reverse side of this Notice on or before June 1, 2026 to facilitate timely delivery. There is no charge to you for requesting a copy. Important information regarding the Internet availability of the Company's proxy materials, instructions for accessing your proxy materials and voting online, and instructions for requesting paper or e-mail copies of your proxy materials are outlined in this Notice. CONTROL NUMBER STOCKHOLDERS ARE CORDIALLY INVITED TO ATTEND THE ANNUAL MEETING. To the Stockholders of GOLDEN MINERALS COMPANY: The 2026 Annual Meeting of Stockholders of GOLDEN MINERALS COMPANY will be held on June 12, 2026 at 1:00 p.m. Mountain Daylight Time. Notice is hereby given that the Annual Meeting of Stockholders of GOLDEN MINERALS COMPANY will be held on June 12, 2026, at 1:00p.m. Mountain Daylight Time at Embassy Suites by Hilton Denver International Airport, Room Mount Evans, 7001 Yampa Street, Denver, CO 80249, for the following purposes: The Board recommends a vote "FOR" Proposals 1 and 2. 1. To elect five members to the Board of Directors; 2. To ratify the appointment of Haynie & Company as 1a. Jeffrey G. Clevenger our independent registered public accounting firm for 1b. Pablo Castanos the fiscal year ended December 31, 2026. 1c. Deborah J. Friedman 1d. Kevin R. Morano 1e. David H. Watkins NOTE: To conduct any other business properly brought before the Annual Meeting or any adjournment, postponement, or rescheduling thereof.

The Securities and Exchange Commission rules permit us to make our proxy materials available to our stockholders via the Internet. Materials for this Annual Meeting and future meetings may be requested by one of the following methods: CONTROL NUMBER Internet Go to https://web.viewproxy.com/AUMN/2026. Have the 11-digit Control Number available when you access the website and follow the instructions. Telephone Call 1-877-777-2857 Toll Free E-Mail By e-mail at: [email protected] * If requesting material by e-mail, please send a blank e-mail with the company name and your 11-digit Control Number in the subject line. No other requests, instructions, or other inquiries should be included within this email request. VOTING METHODS Via Internet prior to the Annual Meeting: Go to http://www.aalvote.com/AUMN. Have your 11-digit Control Number available and follow the prompts. • Your electronic vote prior to the Annual Meeting authorizes the named proxies to vote your shares in the same manner as if you marked, signed, dated, and returned a proxy card. Use any touch-tone telephone to vote your proxy. Have your proxy card available when you call. Follow the voting instructions to vote your shares. Via Telephone: Call 1-866-804-9616