ECA Marcellus Trust I Unit 2025年度报告

FORM10-K (Mark One)ANNUAL REPORT PURSUANT TO SECTION13 OR 15(d)OF THE SECURITIESEXCHANGEACTOF1934For the fiscal year ended December31, 2025OrTRANSITION REPORT PURSUANT TO SECTION13 OR 15(d)OF THE SECURITIESEXCHANGEACT OF1934For the transition period fromtoCommission File Number001-34800 ECA Marcellus Trust I Securities registered pursuant to Section12(b)of the Act:None Securities registered pursuant to Section12(g)of the Act:None Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule405 of the Securities Act. YesNo. Indicate by check mark if the registrant is not required to file reports pursuant to Section13 or Section15(d)of the Act. YesNo. Indicate by check mark whether the registrant (1)has filed all reports required to be filed by Section13 or 15(d)of the SecuritiesExchange Act of 1934 during the preceding 12months (or for such shorter period that the registrant was required to file such reports),and (2)has been subject to such filing requirements for the past 90days. YesNo Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submittedpursuant to Rule405 of RegulationS-T (§232.405 of this chapter) during the preceding 12months (or for such shorter period that theregistrant was required to submit such files). YesNo Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smallerreporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smallerreporting company,” and “emerging growth company” in Rule12b-2 of the Exchange Act. Large acceleratedfilerAcceleratedfilerNon-acceleratedfilerSmaller reportingcompanyEmerging growth company If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period forcomplying with any new or revised financial accounting standards provided pursuant to Section13(a)of the Exchange Act. Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of theeffectiveness of its internal control over financial reporting under Section404(b)of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by theregistered public accounting firm that prepared or issued its audit report. If securities are registered pursuant to Section12(b)of the Act, indicate by check mark whether the financial statements of theregistrant included in the filing reflect the correction of an error to previously issued financial statements. Indicate by check mark whether any of those error corrections are restatements that required a recovery analysis of incentive-basedcompensation received by any of the registrant’s executive officers during the relevant recovery period pursuant to §240.10D-1(b). Indicate by check mark whether the registrant is a shell company (as defined in Rule12b-2 of the Act). YesNo The aggregate market value of Common Units representing beneficial interests in ECA Marcellus Trust I held by non-affiliates onJune30, 2025, the last business day of the registrant’s most recently completed second fiscal quarter, was $11,091,150. As of March24, 2026, 17,605,000 Common Units representing beneficial interests in ECA Marcellus Trust I were outstanding. Documents Incorporated By Reference: None TABLE OF CONTENTS Forward-Looking Statements2Glossary of Certain Oil and Natural Gas Terms3PARTIItem1.Business6Item1A.Risk Factors21Item1B.Unresolved Staff Comments39Item 1C.Cybersecurity39Item2.Properties41Item3.Legal Proceedings46Item4.Mine Safety Disclosures46PARTIIItem5.Market for Registrant’s Common Equity, Related Unitholder Matters and Issuer Purchases of Equity Securities47Item6.[Reserved]47Item7.Trustee’s Discussion and Analysis of Financial Condition and Results of Operations48Item7A.Quantitative and Qualitative Disclosure About Market Risk52Item8.Financial Statements and Supplementary Data53Item9.Changes in and Disagreements with Accountants on Accounting and Financial Disclosure62Item9A.Controls and Procedures62Item9B.Other Information63Item 9C.Disclosure Regarding Foreign Jurisdictions that Prevent Inspections63PARTIIIItem10.Directors, Executive Officers and Corporate Governance64Item11.Executive Compensation64Item12.Security Ownership of Certain Beneficial Owners and Management and Related Unitholder Matters64Item13.Certain Relationships and Related Transactions, and Director Independence65Item14.Principal Accountant Fees and Services65PARTIVItem15.Exhibitand Financial Statement Schedules66Item 16.Form10-K Summary67SIGNATURES68AppendixA. Report of Ryder Scott Company,L.P.A-1 References to the “Trust” in this document are to ECA Marcellus Trust I. As discussed in “ Business – “Introduction” in Item1, in November2017 Greylock Energy, LLC and certain of its wholly owned subsidiaries acquired substantially all of the gasproductio