GOLD RESOURCE CORP

false 0001160791 0001160791 2026-06-18 2026-06-18 iso4217:USD xbrli:shares iso4217:USD xbrli:shares 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): June 18, 2026 GOLD RESOURCE CORPORATION (Exact name of registrant as specified in its charter) Colorado 001-34857 84-1473173 (State or other jurisdiction of incorporation) (Commission File Number) (I.R.S. Employer Identification Number) 7887 East Belleview Avenue, Suite 1100 Denver , Colorado 80211 (Address of principal executive offices) (Zip Code) Registrant’s telephone number including area code: ( 303 ) 320-7708 (Former name or former address, if changed since last report) 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: ¨ 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: Title of each class Trading Symbol(s) Name of each exchange on which registered Common Stock GORO NYSE American Indicate by check mark whether the registrant is an emerging growth company 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 8.01 Other Events As previously announced, on January 25, 2026, Gold Resource Corporation (the “Company”) entered into an Arrangement Agreement and Plan of Merger, as amended by that certain First Amendment to Arrangement Agreement dated May 15, 2026 (the “Arrangement Agreement”), with Goldgroup Mining Inc., a corporation incorporated under the laws of the province of British Columbia (“Goldgroup”), and Goldgroup Merger Sub Inc., a Colorado corporation and direct, wholly owned subsidiary of Goldgroup (“Purchaser Sub”). The Arrangement Agreement provides that, among other things and subject to the terms and conditions of the Arrangement Agreement, Purchaser Sub will merge with and into the Company, with the Company surviving and continuing as the surviving corporation as a direct, wholly owned subsidiary of Goldgroup (such transaction, the “Merger”). In connection with the Merger, the Company filed a definitive proxy statement (the “Proxy Statement”) with the U.S. Securities and Exchange Commission (the “SEC”) on May 29, 2026. As is common in transactions of this type, multiple lawsuits have been threatened by purported shareholders of the Company, challenging the completeness and accuracy of the disclosure in the Proxy Statement. The supplemental disclosures below should be read in conjunction with the Proxy Statement, available on the SEC’s website at https://www.sec.gov, along with periodic reports and other information the Company files with the SEC. To the extent information herein differs from or updates information contained in the Proxy Statement, the information set forth herein shall supersede or supplement the information in the Proxy Statement. All page references are to the Proxy Statement, and terms used but not defined below have the meanings set forth in the Proxy Statement. The Company and Goldgroup believe the claims in the threatened lawsuits are without merit and that no supplemental disclosures are required under applicable law. However, to eliminate the burden, expense, and uncertainties inherent in such litigation, and without admitting any liability or wrongdoing, the Company is voluntarily making the supplemental disclosures set forth below. Nothing herein shall be deemed an admission of the legal necessity or materiality of any of these disclosures. The Company and Goldgroup specifically deny all allegations in the threatened lawsuits, including that any additional disclosure was or is required. Supplemental Proxy Statement Disclosures The following changes, shown in strikethrough (for deletions) and underline (for additions) text, are made to the second sentence under the heading “Who is entitled to vote at the Special Meeting?” on page 8 As of the record date, there were approximately 161,889,776 163,392,909 Company Shares outstanding, with one vote per share. The following disclosure is added immediately following the first sentence in the sixth paragraph on page 33 None of these agreements contained a “don’t ask, don’t waive” provision that would prevent the counterparty from making a proposal to acquire the Company. The following disclosure is added immediately following the second sentence of the second full paragraph on page 43 The projections provided to ATB Cormark were subject to the assumptions and limitations set forth in the section entitled “— Certain Prospective Financial and Operating Information ” beginning on page 49 of this Proxy Statement. The following disclosure is added to the top of page 49 Certain Prospective Financial and Operating Information The Company does not, as a matter of course, make public projections as to future performance, earnings, or other results due to the inherent unpredictability of projections and their underlying assumptions and estimates. However, the Company provided to Goldgroup, in connection with its due diligence review, certain non-public unaudited financial and operating projections on a stand-alone basis, without giving effect to the Merger, for the period from 2026 through 2030 (the “Company Projections for Gold Resource”). The Company prepared similar financial and operating projections for Goldgroup for the period from 2026 through 2031 based, in part, on Goldgroup’s management model and certain estimates of the Company’s management (the “Company Projections for Goldgroup” and, together with the Company Projections for Gold Resource, are referred to as the “Projections” herein); Goldgroup management was not involved in the preparation of the Company Projections for Goldgroup aside from providing the Company with Goldgroup’s management model. In addition, the Company provided the Projections to ATB Cormark in connection with the preparation of its valuation analyses and fairness opinion, as described in, and subject to the assumptions and limitations as set forth in, the section entitled “— Opinion of Our Financial Advisor .” The Projections were not prepared with a view toward public disclosure. They are only included herein because they were (i) prepared by the Company in connection with due diligence, (ii) made available to the Board in connection with its review of the potential transaction with Goldgroup and its evaluation of strategic alternatives, and (iii) used by ATB Cormark in preparing its valuation analyses and fairness opinion provided to the Board, as described in the section entitled “— Opinion of Our Financial Advisor .” The summary of the Projections is not included to influence any Company stockholder’s decision whether to vote in favor of the proposal to approve the Arrangement Agreement. The Projections may differ from published analyst estimates and forecasts. The Projections do not necessarily comply with published guidelines of the SEC, the provisions of NI 43-101, the guidelines established by the American Institute of Certified Public Accountants for preparation and presentation of financial forecasts, or generally accepted ac