Gold Resource Corporation (NYSE:GORO) (the "Company," "we," "our," or "GRC") announced that it has received notification from the FTSE Russell that following the Company’s previously announced merger (the "Merger") with Goldgroup Mining Inc. ("Goldgroup"), the combined company will not be eligible for inclusion in the Russell 2000 Comprehensive Factor Index beginning on July 20, 2026, as Goldgroup does not meet FTSE Russell’s nationality eligibility requirements within the Russell Index family, apparently based on Goldgroup’s Canadian home country indicators. Previously, GRC had been added to certain Russell Indexes effective after the market close on June 26, 2026 in connection with the annual and semi-annual Russell U.S. Indexes reconstitution. Subject to obtaining all required approvals and the satisfaction or waiver of all required closing conditions for the Merger, the Merger is expected to be consummated after the market close on July 17, 2026.

About GRC:

Gold Resource Corporation is a gold and silver producer, developer, and explorer with its operations centered on the Don David Gold Mine in Oaxaca, Mexico. Under the direction of an experienced board and senior leadership team, the Company’s focus is to unlock the significant upside potential of its existing infrastructure and large land position surrounding the mine in Oaxaca, Mexico and to develop the Back Forty Project in Michigan, USA. For more information, please visit the Company’s website, located at www.goldresourcecorp.com.

Forward-Looking Statements:

This press release contains forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended (the "Securities Act"), and Section 21E of the Securities Exchange Act of 1934, as amended. Forward-looking words such as "plan," "target," "anticipate," "believe," "estimate," "intend" and "expect" and similar expressions are intended to identify such forward-looking statements. Such forward-looking statements include, without limitation, the statements regarding the eligibility of the Company for the Russell 2000 Comprehensive Factor Index and the expected closing of the Merger. All forward-looking statements in this press release are based upon information available to the Company as of the date of this press release, and the Company assumes no obligation to update any such forward-looking statements. Forward-looking statements involve a number of risks and uncertainties, and there can be no assurance that such statements will prove to be accurate. The Company’s actual results could differ materially from those discussed in this press release. Forward-looking statements are subject to risks and uncertainties. Additional risks related to the Company may be found in the periodic and current reports filed with the SEC by the Company, including the Company’s Annual Report on Form 10-K for the year ended December 31, 2025, as amended, which are available on the SEC’s website at https://www.sec.gov.

View source version on businesswire.com: https://www.businesswire.com/news/home/20260717997930/en/

Allen Palmiere

Chief Executive Officer

Gold Resource Corporation

720-459-3854

Allen.Palmiere@GRC-USA.com

www.goldresourcecorp.com