HALLADOR ENERGY CO 10-Q

ITEM 5. OTHER INFORMATION None. Rule 10b5-1 Trading Arrangements During the three months ended March 31, 2026, no director or officer of Hallador adopted or terminated a "Rule 10b5-1 trading arrangement" or " non-Rule 10b5-1 trading arrangement ," as each term is defined in Item 408 of Regulation S-K. ITEM 6. EXHIBITS ​ ​ ​ Exhibit No. ​ ​ ​ Document 1.1 ​ Underwriting Agreement dated January 13, 2026 (1) 10.1 ​ Credit Agreement, dated March 5, 2026, among Hallador Energy Company, the lenders party thereto, the letter of credit issuers party thereto and Texas Capital Bank, as administrative agent incorporated by reference to Form 8-K filed on March 10, 2026 (2) 10.2 ​ Master Power Purchase And Sale Agreement Long-Form Confirmation Letter dated May 1, 2026 * 31.1 ​ SOX 302 Certification - Chief Executive Officer * 31.2 ​ SOX 302 Certification - Chief Financial Officer * 31.3 ​ SOX 302 Certification – Chief Accounting Officer * 32 ​ SOX 906 Certification * 95.1 ​ Mine Safety Disclosures * 101.INS ​ Inline XBRL Instance Document* 101.SCH ​ Inline XBRL Schema Document* 101.CAL ​ Inline XBRL Calculation Linkbase Document* 101.LAB ​ Inline XBRL Labels Linkbase Document* 101.PRE ​ Inline XBRL Presentation Linkbase Document* 101.DEF ​ Inline XBRL Definition Linkbase Document* 104 ​ Cover Page Interactive Data File (embedded with the Inline XBRL document)* ​ ​ ​ ​ *Filed herewith. (1) Incorporated by reference to Form 8-K filed on January 15, 2026. (2) Incorporated by reference to Form 8-K filed on March 10, 2026. ​ ​ ​ ​ ​ 33 Table of Contents SIGNATURES Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized. ​ ​ ​ HALLADOR ENERGY COMPANY ​ ​ Date: May 6, 2026 /s/BRENT K. BILSLAND ​ Brent K. Bilsland, Chairman, President and CEO ​ ​ Date: May 6, 2026 /s/TODD E. TELESZ ​ Todd E. Telesz, CFO ​ ​ Date: May 6, 2026 /s/ERIC VAN DEMAN ​ Eric Van Deman, CAO ​ ​ 34