ECA Marcellus Trust I

Natural Gas Reserves

Ryder Scott estimated natural gas reserves attributable to the Royalty Interests as of December 31, 2025. Numerous uncertainties are inherent in estimating reserve volumes and values, and the estimates are subject to change as additional information becomes available. The reserves actually recovered and the timing of production of the reserves may vary significantly from the estimates.

Proved Reserves of the Royalty Interests. The following table sets forth certain estimated Proved reserves, estimated future net cash flows and the discounted present value thereof attributable to the Royalty Interests, as of December 31, 2025, in each case derived from the Ryder Scott reserve report. The reserve report was prepared by Ryder Scott in accordance with criteria established by the SEC. In accordance with the SEC’s rules, the reserves presented below were determined using the twelve-month unweighted arithmetic average of the first-day-of-the-month price for the period from January 1, 2025 through December 31, 2025, and were held constant for the life of the properties. This yielded an average realized price for natural gas of $2.87 per Mcf. The net revenues attributable to the Trust’s reserves are net of the Trust’s obligation to reimburse Greylock Production for post-production costs. The reserves and cash flows attributable to the Trust’s interests include only the reserves attributable to the Underlying Properties that are expected to be produced within the remaining portion of the 20-year period in which the Trust owns the Royalty Interests as well as the residual interest in the reserves that the Trust will own on the Termination Date. A summary of the Ryder Scott reserve report dated December 19, 2025 is included as Appendix A to this report.

Proved reserves · Proved Gas Reserves (MMcf) · Estimated Future Net Cash Flows · Discounted Estimated Future Net Cash Flows(1)

(Dollars in thousands)

Royalty Interests:

Proved Developed · 14,944 · 32,583 · 17,576

(1) · The present values of future net cash flows for the Royalty Interests were determined using a discount rate of 10% per annum.

Information concerning historical changes in net Proved reserves attributable to the Royalty Interests, and the calculation of the standardized measure of discounted future net cash flows related thereto, is contained in the unaudited supplemental information contained elsewhere in this report. The Trust has not filed reserve estimates covering the Royalty Interests with any other federal authority or agency.

The Reserve Report

Technologies. The reserve report was prepared using decline curve analysis to determine the reserves of individual Producing Wells.

Internal Controls. Ryder Scott, the independent petroleum engineering consultant, estimated, in accordance with appropriate engineering, geologic, and evaluation principles and techniques that are in accordance with practices generally accepted in the petroleum industry, and definitions and guidelines established by the SEC, all of the proved reserve information in this report. These reserves estimation methods and techniques are widely taught in university petroleum curricula and throughout the industry’s ongoing training programs. Although these appropriate engineering, geologic, and evaluation principles and techniques that are in accordance with practices generally accepted in the petroleum industry are based upon established scientific concepts, the application of such principles involves extensive judgment and is subject to changes in existing knowledge and technology, economic conditions and applicable statutory and regulatory provisions. These same industry-wide applied techniques are used in determining the estimated reserve quantities attributable to the Royalty Interests. The technical persons responsible for preparing the reserves estimates presented herein meet the requirements regarding qualifications, independence, objectivity and confidentiality set forth in the Society of Petroleum Engineers’ Standards Pertaining to the Estimating and Auditing of Oil and Gas Reserves Information. Greylock Production’s internal control over its reserve reporting process is designed to result in accurate and reliable estimates in compliance with applicable regulations and guidance. Internal reserve preparation is performed by staff reservoir engineers and geoscientists before review by the Reservoir Engineering Manager. These individuals consult regularly with Ryder Scott during the reserve estimation process to review properties, assumptions, and any new data available. Additionally, Greylock Production’s senior management reviewed and approved all Ryder Scott reserve reports contained herein.

• Declines in the financial position or creditworthiness of Greylock Production or any third-party operators could impede the operation of wells.
• The Trust units may lose value as a result of title deficiencies with respect to the Underlying Properties.
• The natural gas reserves estimated to be attributable to the Underlying Properties of the Trust are depleting assets and production from those reserves will diminish over time. Furthermore, the Trust is precluded from acquiring other oil and gas properties or Royalty Interests to replace the depleting assets and production.
• The amount of cash available for distribution by the Trust will be reduced by the amount of post-production costs, applicable taxes associated with the Trust’s interest, and Trust expenses.
• The Trust has established a cash reserve for contingent liabilities and to pay expenses in accordance with the Trust Agreement, which would reduce proceeds payable to the Trust and distributions to Trust unitholders.
• An increase in the negative basis differential between the price realized by Greylock Production for natural gas produced from the Underlying Properties and the NYMEX or other benchmark price of natural gas could reduce the proceeds to the Trust and therefore the cash distributions by the Trust and the value of Trust units.
• The Trust has no hedges in place to protect against the price risk inherent in holding interest in natural gas, a commodity that is frequently characterized by significant price volatility.
• The ability of Greylock Production to satisfy its obligations to the Trust depends on the financial position of Greylock Production, and in the event of a default by Greylock Production in its obligations to the Trust, or in the event of Greylock Production’s bankruptcy, it would be expensive and time-consuming for the Trust to exercise its remedies.
• The Trust is passive in nature and has no stockholder voting rights in Greylock Production, managerial, contractual or other ability to influence Greylock Production, or control over the field operations of, sale of natural gas from, or development of, the Underlying Properties.
• Greylock Production may sell all or a portion of the Underlying Properties, subject to and burdened by the Royalty Interests. A purchaser of such Underlying Properties could have a weaker financial position and/or be less experienced in natural gas development and production than Greylock Production.
• The Trustee may, under certain circumstances, sell the Royalty Interests and dissolve the Trust. Unless sooner terminated, the Trust will begin to terminate following the end of the 20-year period in which the Trust owns the Term Royalty Interests.
• Conflicts of interest could arise between Greylock Production and the Trust unitholders.
• The Trust is administered by a Trustee who cannot be replaced except at a special meeting of Trust unitholders.
• Financial information of the Trust is not prepared in accordance with GAAP.
• The Trust is a smaller reporting company and benefits from certain reduced governance and disclosure requirements, including that the Trust’s independent registered public accounting firm is not required to attest to the effectiveness of the Trust’s internal control over financial reporting. The Trust cannot be certain if the omission of reduced disclosure requirements applicable to smaller reporting companies will make the Trust Units less attractive to investors.
• Trust unitholders have limited ability to enforce provisions of the Royalty Interests, and Greylock Production’s liability to the Trust is limited.
• The Trust units are traded on the OTCID Basic Market. As a result, Trust unitholders may have more difficulty selling Trust units or obtaining accurate quotations of the Trust units than if the Trust units were traded on a national securities exchange.
• The Private Investors may sell additional Trust units, and such sales could have an adverse effect on the trading price of the Trust units.
• Courts outside of Delaware may not recognize the limited liability of the Trust unitholders provided under Delaware law.
• Greylock Production is subject to complex federal, state, local and other laws and regulations that could adversely affect the cost, manner or feasibility of conducting its operations or expose Greylock Production to significant liabilities.
• The operations of Greylock Production are subject to environmental laws and regulations that may result in significant costs and liabilities.
• Climate change laws and regulations restricting emissions of “greenhouse gases” could result in increased operating costs and reduced demand for the natural gas that Greylock Production produces, while the physical effects of climate change could disrupt Greylock Production’s production and cause Greylock Production to incur significant costs in preparing for or responding to those effects.
• Cyber-attacks or other failures in telecommunications or information technology systems could result in information theft, data corruption and significant disruption of Greylock Energy’s business operations.
• Cyber-attacks or other failures in telecommunications or IT systems could result in information theft, data corruption and significant disruption of the Trustee’s operations.
• Tax Risks Related to the Trust Units
• The Trust’s tax treatment depends on its status as a partnership for United States federal income tax purposes. At the inception of the Trust, the Trust received an opinion from tax counsel that the Trust will be treated as a partnership for United States federal income tax purposes. If the IRS were to treat the Trust as a corporation for United States federal income tax purposes, then its cash available for distribution would be substantially reduced.
• If the Trust were subjected to a material amount of additional entity-level taxation by Pennsylvania or any other states, the Trust’s cash available for distribution to Trust unitholders would be reduced.
• If enacted, severance taxes in Pennsylvania could materially increase the applicable taxes that are borne by the Trust.
• The tax treatment of publicly traded partnerships or an investment in the Trust units could be affected by recent and potential legislative, judicial or administrative changes and differing interpretations, possibly on a retroactive basis.
• The Trust prorates items of income, gain, loss and deduction between transferors and transferees of the Trust units each month based upon the ownership of the Trust units on the first day of each month, instead of on the basis of the date a particular Trust unit is transferred.
• If the IRS contests the United States federal income tax positions the Trust takes, the market for the Trust units may be adversely impacted and the cost of any IRS contest will reduce the Trust’s cash available for distribution.
• Each Trust unitholder is required to pay taxes on the Trust unitholder’s share of the Trust’s income even if a unitholder does not receive any cash distributions from the Trust.
• Tax gain or loss on the disposition of the Trust units could be more or less than expected.
• Tax-exempt organizations and non-United States persons face unique tax issues from owning the Trust units that may result in adverse tax consequences to them.
• The Trust treats each purchaser of Trust units as having the same economic attributes without regard to the actual Trust units purchased. The IRS may challenge this treatment, which could adversely affect the value of the Trust units.
• A Trust unitholder whose Trust units are loaned to a “short seller” to cover a short sale of Trust units may be considered as having disposed of those Trust units. If so, he would no longer be treated for tax purposes as a partner with respect to those Trust units during the period of the loan and may recognize gain or loss from the disposition.
• The Trust may adopt certain valuation methodologies that may affect the income, gain, loss and deduction allocable to the Trust unitholders. The IRS may challenge this treatment, which could adversely affect the value of the Trust units.
• Certain United States federal income tax preferences currently available with respect to natural gas production may be eliminated as a result of future legislation.