Commitments and Contingencies	9 Months Ended
Sep. 30, 2026
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Merger-Related Litigation Counsel for TXNM has received a number of demand letters from certain law firms on behalf of individuals who are purported TXNM shareholders, accompanied by draft complaints naming TXNM and its directors as defendants and alleging that TXNM’s preliminary proxy statement with respect to the Merger omitted or misrepresented certain material information. Such draft complaints include a request for injunctive relief with respect to the TXNM shareholder vote to approve, and the closing of, the Merger, as well as other remedies, including counsel fees. In August 2025, reported shareholders filed complaints in New York state court alleging disclosure violations and seeking injunctive relief. TXNM believes that the allegations set forth in the demand letters, draft complaints, and complaints are without merit and will defend against such actions vigorously. Overview There are various claims and lawsuits pending against the Company. In addition, the Company is subject to federal, state, and local environmental laws and regulations and periodically participates in the investigation and remediation of various sites. In addition, the Company periodically enters into financial commitments in connection with its business operations. Also, the Company is involved in various legal and regulatory proceedings in the normal course of its business. See Note 12. It is not possible at this time for the Company to determine fully the effect of all litigation and other legal and regulatory proceedings on its financial position, results of operations, or cash flows. With respect to some of the items listed below, the Company has determined that a loss is not probable or that, to the extent probable, cannot be reasonably estimated. In some cases, the Company is not able to predict with any degree of certainty the range of possible loss that could be incurred. The Company assesses legal and regulatory matters based on current information and makes judgments concerning their potential outcome, giving due consideration to the nature of the claim, the amount and nature of any damages sought, and the probability of success. Such judgments are made with the understanding that the outcome of any litigation, investigation, or other legal proceeding is inherently uncertain. The Company records liabilities for matters where it is probable a loss has been incurred, and the amount of loss is reasonably estimatable. The actual outcomes of the items listed below could ultimately differ from the judgments made and the differences could be material. The Company cannot make any assurances that the amount of reserves or potential insurance coverage will be sufficient to cover the cash obligations that might be incurred as a result of litigation or regulatory proceedings. Except as otherwise disclosed, the Company does not expect that any known lawsuits, environmental costs, or commitments will have a material effect on its financial condition, results of operations, or cash flows. Additional information concerning commitments and contingencies is contained in Note 16 of the Notes to Consolidated Financial Statements in the 2025 Annual Reports on Form 10-K. Commitments and Contingencies Related to the Environment Nuclear Spent Fuel and Waste Disposal Nuclear power plant operators are required to enter into spent fuel disposal contracts with the DOE that require the DOE to accept and dispose of all spent nuclear fuel and other high-level radioactive wastes generated by domestic power reactors. Although the Nuclear Waste Policy Act required the DOE to develop a permanent repository for the storage and disposal of spent nuclear fuel by 1998, the DOE announced that it would not be able to open the repository by 1998 and sought to excuse its performance of these requirements. In November 1997, the DC Circuit issued a decision preventing the DOE from excusing its own delay but refused to order the DOE to begin accepting spent nuclear fuel. Based on this decision and the DOE’s delay, a number of utilities, including APS (on behalf of itself and the other PVNGS owners, including PNM), filed damages actions against the DOE in the Court of Federal Claims. The lawsuits filed by APS alleged that damages were incurred due to DOE’s continuing failure to remove spent nuclear fuel and high-level waste from PVNGS. APS and the DOE entered into a settlement agreement, subsequently extended, that established a process for the payment of claims for costs incurred through December 31, 2025. Under the settlement agreement, APS must submit claims annually for payment of allowable costs. APS is currently in the process of extending the settlement to cover costs paid through December 31, 2028. PNM records estimated claims on a quarterly basis. The benefit from the claims is passed through to customers under the FPPAC. PNM estimates that it will incur approximately $55.6 million (in 2023 dollars) for its share of the costs related to the on-site interim storage of spent nuclear fuel at PVNGS for the remaining term of the operating licenses. PNM accrues these costs as a component of fuel expense as the nuclear fuel is consumed. At September 30, 2026 and December 31, 2025, PNM had a liability for interim storage costs of $16.9 million and $15.5 million, which is included in other deferred credits. PVNGS has sufficient capacity at its on-site Independent Spent Fuel Storage Installation (“ISFSI”) to store all of the nuclear fuel that will be irradiated during the initial operating license period, which ends in December 2027. Additionally, PVNGS has sufficient capacity at its on-site ISFSI to store a portion of the fuel that will be irradiated during the period of extended operation, which ends in November 2047. If uncertainties regarding the U.S. Government’s obligation to accept and store spent fuel are not favorably resolved, APS will evaluate alternative storage solutions that may obviate the need to expand the ISFSI to accommodate all of the fuel that will be irradiated during the period of extended operation. The New Mexico Energy Transition Act The New Mexico Energy Transition Act (“ETA”) sets a statewide standard that requires investor-owned electric utilities to have specified percentages of their electric-generating portfolios be from renewable and zero-carbon generating resources. The passage of the ETA amended the REA to require utilities operating in New Mexico to have renewable portfolios equal to 50% by 2030, 80% by 2040, and 100% zero-carbon energy by 2045. The amendments also allow for the recovery of undepreciated investments and decommissioning costs related to qualifying EGUs that the NMPRC has required be removed from retail jurisdictional rates, provided replacement resources to be included in retail rates have lower or zero-carbon emissions. The ETA requires the NMPRC to review and approve utilities’ annual renewable portfolio plans to ensure compliance with the RPS. Also pursuant to the ETA, the NM Environmental Improvement Board adopted standards of performance that limit CO2 emissions to no more than 1,100 lbs. per MWh beginning January 1, 2023, for new and existing coal-fired EGUs with original installed capacities exceeding 300 MW. The ETA provides for a transition from fossil-fuel generation resources to renewable and other carbon-free resources through certain provisions relating to the abandonment of coal-fired generating facilities. These provisions include the use of energy transition bonds to finance certain costs of abandoning coal-fired facilities that are retired prior to January 1, 2023, for facilities operated by a “qualifying utility,” or prior to January 1, 2032, for facilities that are not operated by a qualifying utility. The amount of energy transition bonds that can be issued to recover abandonment costs is limited to the lesser of $375.0 million or 150% of the undepreciated investment of the facility as of the abandonment date. Proceeds provided by energy transition bonds must be used only for purposes related to providing utility service to customers and to pay energy transition costs (as defined by the ETA). These costs may include plant decommissioning and coal mine reclamation costs provided those costs have not previously been recovered from customers or disallowed by the NMPRC or by a court order. Proceeds from energy transition bonds may also be used to fund severances for employees of the retired facility and related coal mine and to promote economic development, education and job training in areas impacted by the retirement of the coal-fired facilities. Energy transition bonds must be issued under a NMPRC-approved financing order, are secured by “energy transition property,” are non-recourse to the issuing utility, and are repaid by a non-bypassable charge paid by all customers of the issuing utility. These customer charges are subject to an adjustment mechanism designed to provide for timely and complete payment of principal and interest due under the energy transition bonds. The ETA also provides that utilities must obtain NMPRC approval of competitively procured replacement resources that shall be evaluated based on their cost, economic development opportunity, ability to provide jobs with comparable pay and benefits to those lost upon retirement of the facility, and that do not exceed emissions thresholds specified in the ETA. In determining whether to approve replacement resources, the NMPRC must give preference to resources with the least environmental impacts, those with higher ratios of capital costs to fuel costs, and those located in the school district of the abandoned facility. The ETA also provides for the procurement of energy storage facilities and gives utilities discretion to maintain, control, and operate these systems to ensure reliable and efficient service. The ETA has had and will have a significant impact on PNM’s future generation portfolio, including PNM’s retirement of SJGS in 2022. PNM cannot predict the full impact of the ETA with respect to Four Corners or the outcome of its future generating resource abandonment and replacement resource filings with the NMPRC. Clean Transportation Fuel Program (“CTFP”) In April 2026, New Mexico became the fourth state to adopt a clean fuel standard by launching the CTFP administered by NMED. The primary goal of the CTFP is to reduce overall climate pollution from transportation fuel used in New Mexico by establishing annual statewide CI standards for transportation fuel, allocating credits and calculating deficits for importers, producers or dispensers of transportation fuel in New Mexico based on whether their fuel is below or above the CI standards. The CTFP also creates a marketplace where CI standards may be met by generating credits from importing or producing low-carbon fuel, using banked credits, or acquiring credits. PNM has opted into the CTFP as a low-carbon fuel producer to participate in this marketplace by generating credits and selling credits. PNM expects the first batch of credits to be produced from residential EV charging to be available towards the end of 2026 and sold in the marketplace within the first half of 2027. PNM will use the proceeds from the sale of the credits to further support transportation electrification through the current TEP rider. The Clean Air Act Regional Haze Pursuant to the CAA, states are required to establish goals for improving visibility in national parks and wilderness areas (also known as Class I areas) and to develop long-term strategies for reducing emissions of air pollutants that cause visibility impairment in their own states and for preventing degradation in other states. States must establish a series of interim goals to ensure continued progress by adopting a new SIP every ten years. In the first SIP planning period, states were required to conduct Best Available Retrofit Technology determinations for certain covered facilities, including utility boilers, built between 1962 and 1977 that have the potential to emit more than 250 tons per year of visibility impairing pollution. For all future SIP planning periods, states must evaluate whether additional emissions reduction measures may be needed to continue making reasonable progress toward natural visibility conditions. SIPs for the second planning period were due in July 2021, which deadline NMED was unable to meet. During NMED’s preparation of the SIP for the second compliance period, PNM was notified that a regional haze four-factor analysis for SJGS was not required since PNM retired its share of SJGS in 2022. NMED petitioned the NM Environmental Improvement Board to adopt a proposed SIP and submitted a final revised plan to the NM Environmental Improvement Board in March 2025. PNM submitted comments on the proposed SIP in response to a request for comments by NMED. No PNM generating stations were identified as reasonable progress units under the adopted SIP indicating that no additional emissions reductions measures may be necessary at this time. On March 11, 2026, the NMED submitted a SIP revision for the second planning period requesting approval by EPA. On March 12, 2025, as part of EPA’s list of 31 deregulatory actions, EPA announced it would restructure the Regional Haze Program. On October 2, 2025, EPA published an advanced notice of proposed rulemaking to solicit information from the public to help develop regulatory changes on the implementation and structure of the Regional Haze Rule (“RHR”). The advanced notice itself does not impose any requirements but requests input on how EPA can revise the RHR to streamline regulatory requirements impacting states’ visibility improvement obligations. Comments were due December 1, 2025. On December 31, 2025, EPA extended the deadline for the third planning period SIPs to July 31, 2031. In February 2026, EPA updated its guidance to ensure that the SIPs account for grid reliability and strategies to prevent premature plant closures. Carbon Dioxide Emissions In 2015, EPA established standards to limit CO2 emissions from power plants, including (1) Carbon Pollution Standards for new, modified, and reconstructed power plants; and (2) the Clean Power Plan for existing power plants. Challengers successfully petitioned the U.S. Supreme Court for a stay of the Clean Power Plan. In 2019, EPA repealed the Clean Power Plan, promulgated the ACE Rule, and revised the implementing regulations for all emission guidelines. The ACE Rule was also challenged, and on January 19, 2021, the DC Circuit issued an opinion in American Lung Association and American Public Health Association v. EPA, et al., vacating the ACE Rule. Numerous parties sought review by the U.S. Supreme Court, and on June 30, 2022, the U.S. Supreme Court held that the “generation shifting” approach in the Clean Power Plan exceeded the powers granted to EPA by Congress. Of broader significance in administrative law, the Court’s opinion expressly invoked the “major question” doctrine, which requires rules involving issues of “vast economic or political significance” to be supported by clear statutory authorization. In cases where there is no clear statement of authority, courts need not defer to the agency’s statutory interpretation on “major questions.” The decision sets legal precedent for future rulemakings by EPA and other federal regulatory agencies whereby the agencies’ authority may be limited based upon similar reasoning. The litigation over the Carbon Pollution Standards remains held in abeyance but could be reactivated by the parties upon a determination by the court that reconsideration of the rule has concluded. In 2024, EPA adopted regulatory actions under CAA Sections 111(b) and (d) to replace the Clean Power Plan and the ACE Rule. The final rules included revised new source performance standards under CAA Section 111(b) for all new natural gas-fired combustion turbines and emission guidelines under CAA Section 111(d) requiring states to develop standards of performance for GHG emissions from existing fossil-fuel-fired electric steam generating units. In the final rules, EPA determined that the standards for existing coal- or gas-fired steam generating units must be based on the use of either CCS (long-term), natural gas co-firing (medium-term), or exempt from the rule via early retirement. The standards for new combustion turbines must be based on CCS (base load), efficient simple cycle design (intermediate load), or lower-emitting fuels (low load). Over a dozen states, several industry groups and some power companies and labor unions filed challenges to the rule at the DC Circuit. On January 20, 2025, President Trump issued several executive orders directing his Administration to review all agency actions and suspend, revise, or rescind those identified as imposing an undue burden on domestic energy resources. On March 12, 2025, as part of EPA’s reconsideration of 31 environmental regulations, EPA announced it will reconsider the previous Administration’s regulations on GHG standards and guidelines for power plants. On June 17, 2025, EPA published a proposed rule in the Federal Register with two alternatives to repeal or revise the GHG emission standards for EGUs. EPA primarily proposed to find that GHG emissions from fossil fuel-fired power plants “do not contribute significantly to dangerous air pollution” under the meaning of CAA Section 111, which would preclude EPA from regulating GHG emissions from those plants. As a result, EPA proposed to repeal all GHG standards for the power sector promulgated under CAA Section 111 in both 2015 and 2024. EPA also proposed, in the alternative, to find that CCS is not adequately demonstrated and that neither CCS nor gas co-firing are the best system of emission reduction for GHG emissions from power plants, which findings also support repeal of those specific requirements from the rules adopted in 2024. Comments were due by September 15, 2025. On September 14, 2026, EPA published a notice of its decision to finalize the alternative proposal to partially repeal the 2024 standards, including the CCS-based standards and all of the standards for existing steam generating units. That final rule is expected to be effective on November 16, 2026, and it has been challenged by numerous parties in the DC Circuit. At the same time EPA issued the notice of a final partial repeal of the 2024 standards, EPA also issued a supplemental proposal on the subject of whether EPA may regulate GHG emissions from the power sector under CAA Section 111 at all, similar to the primary proposal issued in 2025 but under a different legal theory focused on whether the emissions constitute “air pollution” anticipated to “endanger human health and welfare.” Comments on that supplemental proposal are due on November 2, 2026. If finalized as proposed, the supplemental proposal would result in the repeal of all of the remaining GHG standards from EPA’s 2015 and 2024 rulemakings, including the efficiency standards for natural gas-fired combustion turbines and the partial CCS requirements for new steam generating units. In 2021, then President Biden signed an extensive executive order aimed at addressing a wide range of issues, including establishing climate change concerns as an essential element of U.S. foreign and security policy, identifying a process to determine the U.S. INDC under the Paris Agreement, and establishing a Special Presidential Envoy for Climate that would sit on the National Security Council. On April 22, 2021, at the Earth Day Summit, as part of the U.S.’s re-entry into the Paris Agreement, then President Biden unveiled the goal to cut U.S. emissions by 50% - 52% from 2005 levels by 2030. The 2030 emissions goal supported other climate goals which included a carbon pollution-free power sector by 2035 and a net-zero emissions economy by no later than 2050. In an executive order issued on January 20, 2025, President Trump ordered his Administration to withdraw the U.S. from the Paris Agreement and from any agreement, pact, accord, or similar commitment made under the United Nations Framework Convention on Climate Change. On August 1, 2025, EPA published a proposal to rescind the 2009 final rule commonly known as the Endangerment Finding. In the Endangerment Finding, EPA found that current and projected atmospheric concentrations of the well-mixed combination of six GHGs threaten public health and welfare, and that the combined emissions of these GHGs from new motor vehicles and engines contribute to the GHG pollution that threatens public health and welfare. On February 12, 2026, the rule was finalized as proposed, repealing all GHG emission standards for certain vehicles and engines promulgated on the basis of the Endangerment Finding. While the Endangerment Finding did not directly impose any requirements on EGUs, EPA cited the Endangerment Finding as a basis for its authority to regulate GHG emissions from EGUs under CAA Section 111, and EPA has identified that reliance on the Endangerment Finding as a basis for its supplemental proposal to find that CAA Section 111 does not authorize EPA to regulate GHG emissions from the power sector. PNM’s review of the GHG emission reductions standards that have or may occur as a result of legislation or regulation is ongoing. We are currently determining what impact, if any, the final rules will have on our business, results of operations, and financial condition. National Ambient Air Quality Standards (“NAAQS”) The CAA requires EPA to set NAAQS for pollutants reasonably anticipated to endanger public health or welfare. EPA has set NAAQS for certain pollutants, including NOx, SO2, ozone, and particulate matter. NOx Standard – In 2018, EPA published the final rule to retain the current primary health-based NOx standards of which NO2 is the constituent of greatest concern and is the indicator for the primary NAAQS. EPA concluded that the current 1-hour and annual primary NO2 standards are requisite to protect public health with an adequate margin of safety. The rule became effective on May 18, 2018. The State of New Mexico has attained the current NOx NAAQS standards. SO2 Standard – In 2019, EPA announced its final decision to retain, without changes, the primary health-based NAAQS for SO2. Specifically, EPA retained the current 1-hour standard for SO2, which is 75 parts per billion, based on the 3-year average of the 99th percentile of daily maximum 1-hour SO2 concentrations. In 2021, EPA published in the Federal Register the initial air quality designations for all remaining areas not yet designated under the 2010 SO2 Primary NAAQS. All areas of New Mexico have been designated attainment/unclassifiable through four rounds of designations by EPA. Ozone Standard – In 2015, EPA finalized the new ozone NAAQS and lowered both the primary and secondary 8-hour standard from 75 to 70 parts per billion. With ozone standards becoming more stringent, fossil-fueled generation units will come under increasing pressure to reduce emissions of NOx and volatile organic compounds since these are the pollutants that form ground-level ozone. During 2017 and 2018, EPA released rules establishing area designations for ozone. In those rules, San Juan County, New Mexico, where Four Corners is located, is designated as attainment/unclassifiable and only a small area in Doña Ana County, New Mexico is designated as marginal non-attainment. Although Afton Generating Station is located in Doña Ana County, it is not located within the small area designated as non-attainment for the 2015 ozone standard. PNM does not believe there will be material impacts to its facilities because of the non-attainment designation of the small area within Doña Ana County. Until EPA approves attainment designations for the Navajo Nation and releases a proposal to implement the revised ozone NAAQS, PNM is unable to predict what impact the adoption of these standards may have on Four Corners. On July 13, 2020, EPA proposed to retain the existing ozone NAAQS based on a review of the full body of currently available scientific evidence and exposure/risk information, but on August 21, 2023, EPA announced an entirely new review of the ozone standard. PNM cannot predict the outcome of this matter. In 2019, EPA issued findings that several states, including New Mexico, had failed to submit interstate transport SIPs for the 2015 8-hour ozone NAAQS, triggering an obligation for EPA to issue a FIP within two years. In response, NMED submitted a Good Neighbor SIP on July 27, 2021, that demonstrates that there are no significant contributions from New Mexico to downwind problems in meeting the federal ozone standard. On March 15, 2023, EPA Administrator Regan signed a final action imposing a FIP on multiple states but did not include a FIP for New Mexico because the most updated modeling available at the time of the proposal confirmed the state did not contribute to downwind ozone nonattainment or maintenance areas. However, the updated modeling EPA used in the final rule indicated that New Mexico may be significantly contributing to one or more non-attainment or maintenance areas. In light of that modeling result, on February 16, 2024, the EPA published a proposed rule partially disapproving the SIPs for New Mexico and four other states (Arizona, Iowa, Kansas, and Tennessee) and expanding the Good Neighbor FIP to apply to these states. The FIP aspect of the proposed rule would have required fossil fuel-fired power plants in these five states to participate in an allowance-based ozone season NOx emissions trading program beginning in 2025, but the outgoing Biden Administration did not finalize the rule. On March 10, 2025, in the DC Circuit, the EPA filed a motion for voluntary remand of its ozone interstate transport FIP for the 2015 ozone NAAQS to reconsider the rule and had anticipated completing a new rulemaking by Fall 2026. In addition, EPA has now reconsidered the policies underlying its Good Neighbor rule, and, on January 30, 2026, EPA issued a proposed rule to approve New Mexico’s SIP submission because it will not contribute significantly to nonattainment or interfere with maintenance of the 2015 8-hour ozone NAAQS in any other state. If finalized, the EPA will withdraw the prior proposed partial SIP disapproval. PM Standard – In 2023, EPA published, in the Federal Register, a proposal to lower the annual fine PM standard to between 9-10 µg/m3 but retain the rest of its PM standards, including the current daily fine PM standard, the daily coarse PM standard, and the secondary PM standards. The final rule was published on March 6, 2024, lowering the primary annual PM 2.5 NAAQS to 9 ug/m3, and became effective May 6, 2024. States will have until March 2032 to attain compliance with the new standard for any areas designated as nonattainment. This implementation process also applies to the Albuquerque-Bernalillo County Environmental Health Department who may combine efforts with NMED. However, even before any designations are made, the new standard is effective for conducting required modeling for permit applications and revisions. The lower standard is expected to result in new nonattainment areas throughout the country and could prompt additional PM control requirements, but PNM cannot predict the impacts of the outcome of future rulemaking. The PM standard was challenged in the D.C. Circuit, and, following the change in administration, EPA filed a motion for voluntary vacatur of the rule, but the court denied that motion and upheld the new standard on June 26, 2026. The Northern District of California has ordered EPA to promulgate final designations for all areas of the country no later than February 6, 2027. Cooling Water Intake Structures In 2014, EPA issued a rule establishing national standards for certain cooling water intake structures at existing power plants and other facilities under the Clean Water Act to protect fish and other aquatic organisms by minimizing impingement mortality (the capture of aquatic wildlife on intake structures or against screens) and entrainment mortality (the capture of fish or shellfish in water flow entering and passing through intake structures). To minimize impingement mortality, the rule provides operators of facilities, such as Four Corners, seven options for meeting Best Technology Available (“BTA”) standards for reducing impingement. The permitting authority must establish the BTA for entrainment on a site-specific basis, taking into consideration an array of factors, including endangered species and social costs and benefits. Affected sources must submit source water baseline characterization data to the permitting authority to assist in the BTA determination. Compliance deadlines under the rule are tied to permit renewals, including any subject to a schedule of compliance established by the permitting authority in the permit itself. In 2018, several environmental groups sued EPA Region IX in the U.S. Court of Appeals for the Ninth Circuit over EPA’s failure to timely reissue the Four Corners NPDES permit. The petitioners asked the court to issue a writ of mandamus compelling EPA Region IX to take final action on the pending NPDES permit by a reasonable date. EPA subsequently reissued the NPDES permit. The permit did not contain conditions related to the cooling water intake structure rule, because EPA determined that the facility had achieved BTA for both impingement and entrainment by operating a closed-cycle recirculation system. Several environmental groups filed a petition for review with EPA’s Environmental Appeals Board (“EAB”) concerning the reissued permit. The environmental groups alleged that the permit was reissued in contravention of the Clean Water Act and did not contain limits or conditions required by EPA’s ELG applicable to Four Corners or EPA’s cooling water intake structures rule, among others. EPA withdrew the Four Corners NPDES permit in order to examine the issues raised by the environmental groups and then issued an updated NPDES permit in 2019. The permit was once again appealed to the EAB and was stayed before the effective date, but the EAB issued an order denying the petition for review on September 30, 2020. Thereafter, the Regional Administrator of the EPA signed a notice of final permit decision, and the NPDES permit was issued on November 9, 2020. The permit became effective December 1, 2020. On January 22, 2021, the environmental groups filed a petition for review of the EAB’s decision with the U.S. Court of Appeals for the Ninth Circuit. The September 2019 permit remained in effect pending the outcome of this appeal. On March 21, 2022, EPA provided notice in the Federal Register of a proposed settlement agreement with the environmental groups. The parties subsequently executed the settlement agreement as of May 2, 2022. Under the settlement, the lawsuit was administratively closed through September 6, 2023, during which time a third-party consultant spent 12 months sampling discharges from Four Corners and EPA spent three months completing an analysis. On December 1, 2023, EPA issued a modification, effective December 31, 2023, to the NPDES permit that had been issued on November 9, 2020. The modification applies to permit elements related to effluent discharge. PNM cannot predict whether the analysis required to be performed by EPA under the settlement agreement will result in further changes to the NPDES permit but does not anticipate that it will have a material impact on PNM’s financial position, results of operations, or cash flows. Effluent Limitation Guidelines In 2013, EPA published proposed revised wastewater ELG establishing technology-based wastewater discharge limitations for fossil fuel-fired electric power plants. EPA signed the final Steam Electric ELG rule in 2015. The final rule, which became effective on January 4, 2016, phased in the new, more stringent requirements in the form of effluent limits for arsenic, mercury, selenium, and nitrogen for wastewater discharged from wet scrubber systems and zero discharge of pollutants in ash transport water that must be incorporated into plants’ NPDES permits. The 2015 rule required each plant to comply between 2018 and 2023 depending on when it needed a new or revised NPDES permit. The Steam Electric ELG rule was challenged in the U.S. Court of Appeals for the Fifth Circuit by numerous parties. In 2017, EPA signed a notice indicating its intent to reconsider portions of the rule, and the Fifth Circuit issued an order severing the issues under reconsideration and holding the case in abeyance as to those issues. However, the court allowed challenges to other portions of the rule to proceed. In 2019, the Fifth Circuit granted those challenges and issued an opinion vacating several portions of the rule, specifically those related to legacy wastewater and leachate, for which the court deemed the standards selected by EPA to be arbitrary and capricious. In 2017, EPA published a final rule for postponement of certain compliance dates. The rule postponed the earliest date on which compliance with the ELG for regulated waste streams would be required from November 1, 2018 until November 1, 2020. In 2019, EPA published a proposed rule revising the original ELG while maintaining the compliance dates. In 2020, EPA published in the Federal Register the final Steam Electric ELG and Standards for the Steam Electric Power Generating Point Source Category, revising the final 2015 guidelines for both flue gas desulfurization wastewater and bottom ash transport water. The 2020 rule required compliance with new limits as soon as possible on or after October 13, 2021, but no later than December 31, 2025. In 2021, EPA published notice that it would undertake a supplemental rulemaking to revise the ELG after completing its review of the rules reconsidered in 2020. As part of this process, EPA committed to determine whether more stringent limitations and standards would be appropriate. On March 29, 2023, EPA published the proposed ELG Rule in the Federal Register. The proposed rule included stricter limitations for wastewater discharges for coal-fired facilities but allowed for flexibilities for those coal-powered facilities that would decommission or repower by December 31, 2028, to December 31, 2032. On May 9, 2024, EPA published a final rule to further revise the ELG. This final supplemental rule updated the technology-based limitations applicable to flue gas desulfurization wastewater, bottom ash transport water, and legacy wastewater at existing sources, as well as combustion residual leachate at new and existing sources. The 2024 rule was challenged in the U.S. Court of Appeals for the Eighth Circuit, but the court denied motions for a stay, so the rule remains in effect. On March 12, 2025, EPA announced it would reconsider the ELGs for the steam electric power generating industry. On October 2, 2025, EPA published proposed and direct final rules for extension of deadlines and other provisions. Comments were due November 3, 2025. On November 28, 2025, EPA withdrew the direct final rule due to adverse comments and on December 31, 2025, published a final rule revising various deadlines and other provisions in the 2024 rule. On March 9, 2026, EPA sent a proposed rule to Office of Management and Budget reconsidering the technology-based effluent limitations and standards promulgated in 2024. On May 18, 2026, EPA published its proposed rule revising ELGs for unmanaged combustion residual leachate. Comments were due June 17, 2026. The final rule is expected to be published in March 2027. Reeves Station discharges cooling tower blowdown to a publicly owned treatment plant and no longer holds an NPDES permit; therefore, it is expected that no ELG requirements will be imposed. See “Cooling Water Intake Structures” above for additional discussion of Four Corners’ current NPDES permit. Four Corners may be required to change equipment and operating practices affecting boilers and ash handling systems, as well as change its waste disposal techniques during the next NPDES permit renewal. PNM is unable to predict the outcome of these matters or a range of the potential costs of compliance. Santa Fe Generating Station PNM and NMED are parties to agreements under which PNM has installed a remediation system to treat water from a City of Santa Fe municipal supply well and an extraction well to address gasoline contamination in the groundwater at the site of PNM’s former Santa Fe Generating Station and service center. A 2008 NMED site inspection report states that neither the source nor extent of contamination at the site has been determined and that the source may not be the former Santa Fe Generating Station. During 2013 and 2014, PNM and NMED collected additional samples that showed elevated concentrations of nitrate and volatile organic compounds in some of the monitoring wells at the site. In addition, one monitoring well contained free-phase hydrocarbon products. PNM collected a sample of the product for “fingerprint” analysis. The results of this analysis indicated the product was a mixture of older and newer fuels. The presence of newer fuels in the sample suggests the hydrocarbon product likely originated from off-site sources. In 2015, PNM and NMED entered into a memorandum of understanding to address changing groundwater conditions at the site under which PNM agreed to continue hydrocarbon investigation under the supervision of NMED. Qualified costs are eligible for payment through the New Mexico Corrective Action Fund (“CAF”), which is administered by the NMED Petroleum Storage Tank Bureau. In 2019, PNM received notice from NMED that an abatement plan for the site is required to address concentrations of previously identified compounds, unrelated to those discussed above, found in the groundwater. NMED approved PNM’s abatement plan proposal, which covers ongoing field work monitoring and reporting. Additional monitoring well installations along with periodic groundwater sampling and reporting under NMED-approved CAF and abatement plan requirements have continued and support PNM’s contention that off-site sources have impacted, and are continuing to impact, the local groundwater in the vicinity of the former Santa Fe Generating Station. The City of Santa Fe has stopped operating its well at the site, which is needed for PNM’s groundwater remediation system to operate. As a result, PNM has stopped performing remediation activities at the site. However, PNM’s monitoring and other abatement activities at the site are ongoing and will continue until the groundwater meets applicable federal and state standards or until NMED determines that remediation is not required, whichever is earlier. PNM is also in communications with the City of Santa Fe to determine when operations at the site might resume. PNM is not able to assess the duration of this project or estimate the impact on its obligations if PNM is required to resume groundwater remediation activities at the site. PNM is unable to predict the outcome of these matters. Coal Combustion Residuals Waste Disposal CCRs consisting of fly ash, bottom ash, and gypsum generated from coal combustion and emission control equipment at SJGS have been disposed of in the surface mine pits adjacent to the plant. SJGS does not operate any onsite CCR impoundments or landfills. The NMMMD currently regulates mine reclamation activities at the San Juan mine, including placement of CCRs in the surface mine pits, with federal oversight by the OSM. APS disposes of CCRs in onsite ponds and dry storage areas at Four Corners. Ash management at Four Corners is regulated by EPA and the New Mexico State Engineer’s Office. EPA’s 2015 coal ash rule included a non-hazardous waste determination for coal ash and sets minimum criteria for existing and new CCR landfills and surface impoundments. In 2016, the Water Infrastructure Improvements for the Nation Act (the “WIIN Act”) was signed into law to address critical water infrastructure needs in the U.S. and contained a number of provisions related to CCRs. Among other things, the WIIN Act allowed, but did not require, states to develop and submit CCR permit programs for EPA approval, provided flexibility for states to incorporate EPA’s 2015 rule for CCRs or develop other criteria that are at least as protective as EPA’s rule, and required EPA to approve state permit programs within 180 days of submission by the state. Because states are not required to implement their own CCR permit programs, EPA was required to develop a federal permit program in states that chose not to implement a program, subject to congressional funding. Until state or federal permit programs are in effect, the 2015 rule continues to be self-implementing in nature, subject to enforcement by EPA or citizen groups. For facilities located within the boundaries of Native American reservations, such as the Navajo Nation where Four Corners is located, EPA is required to develop a federal permit program regardless of appropriated funds. In 2018, EPA published a rule that constitutes “Phase One, Part One” of its ongoing reconsideration and revision of the 2015 CCR rule. The final Phase One, Part One rule extended the deadline to allow EGUs with unlined impoundments or that fail to meet the uppermost aquifer requirement to continue to receive coal ash until October 31, 2020, which was again extended by subsequent amendments. The rule also authorized a “Participating State Director” or EPA to approve suspension of groundwater monitoring requirements and to issue certifications related to the location restrictions, design criteria, groundwater monitoring, remedy selection and implementation. The rule also modified groundwater protection standards for certain constituents, which include cobalt, molybdenum, lithium, and lead without a maximum contamination level. In 2019, EPA published a second round of proposed revisions, which are commonly referred to as the “Phase Two” revisions, to address reporting and accessibility to public information, “CCR piles” and “beneficial use” definitions, and the requirements for management of CCR piles. EPA reopened and extended the Phase Two comment period several times. To date, EPA has not yet finalized provisions in Phase Two related to beneficial use of CCR and CCR piles. Since its Phase Two proposal, EPA has finalized three other rules addressing various CCR rule provisions. In 2020, EPA promulgated its proposed Holistic Approach to Closure Part A (“Part A”), which set forth a new deadline of April 11, 2021, for companies to initiate closure of unlined CCR impoundments. In accordance with the DC Circuit’s vacatur of portions of the 2015 CCR Rule, Part A also changed the classification of compacted soil-lined or clay-lined surface impoundments from “lined” to “unlined”, triggering closure or retrofit requirements for those impoundments. In addition, Part A delineated a process for owners/operators to submit requests for alternative closure deadlines. EPA also issued the Holistic Approach to Closure Part B (“Part B”) in 2020, which delineated the process for owners/operators to submit alternate liner demonstrations for clay-lined surface impoundments that could otherwise meet applicable requirements. This rule did not include beneficial use of CCR for closure, which EPA explained would be addressed in subsequent rulemaking actions. On May 18, 2023, EPA published a proposed rule establishing the regulatory requirements for inactive surface impoundments at inactive facilities and a new category of regulated unit called a CCR management unit (“CCRMU”), including groundwater monitoring, corrective action, closure, and post-closure care requirements for all CCR management units (regardless of how or when that CCR was placed), and several technical corrections to the existing regulations. Comments on the proposed rule were due July 17, 2023. On May 8, 2024, EPA published a final rule that extended federal CCR regulatory requirements to (1) inactive CCR surface impoundments at inactive utilities and (2) CCRMU, including CCR impoundments and landfills that closed prior to the effective date of the 2015 CCR rule, inactive CCR landfills, and other areas where CCR was managed directly on the land (“Legacy Rule”). The Legacy Rule became effective on November 8, 2024. EPA included deferral options for smaller CCRMU containing between one and 1,000 tons of CCR, CCRMU located beneath critical infrastructure or large buildings or structures vital to the continuation of current site activities, and CCRMU that closed prior to the effective date of the new rule (subject to certain eligibility conditions). EPA also codified the controversial definitions of infiltration and liquids that were litigated in the DC Circuit. Six petitions for review of the Legacy Rule were filed and were consolidated into one case by the DC Circuit. The Utility Solid Waste Activities Group, of which TXNM is a member, is a petitioner jointly with the National Rural Electric Cooperative Association, and American Public Power Association. The U.S. Supreme Court denied a requested stay of the rule by East Kentucky Power Cooperative. The DC Circuit agreed to hold the case in abeyance pending the outcome of EPA’s reconsideration of the Legacy Rule, with status reports due on March 16, 2026, and at 90-day intervals thereafter. On July 22, 2025, EPA published a final rule and companion proposal revising the compliance deadlines for CCRMU requirements under the Legacy Rule. In September 2025, EPA withdrew the direct final rule due to adverse comments but subsequently issued a final extension rule on February 6, 2026, delaying the deadline to complete the “Facility Evaluation Report Part 1” until February 9, 2027, and extending all subsequent deadlines, as well. The final extension rule was published in the Federal Register on February 10, 2026. On April 13, 2026, EPA published proposed Legacy Rule/CCRMU Amendments that, among other things, would rescind all the requirements related to CCRMU and authorize site-specific tailoring of certain rule requirements through federal permits or approved state permits. The comment period for that proposal ended June 29, 2026. PNM submitted comments through EEI, relating to the definitions of CCRMU but not related to the federal permit program for CCR as there are no CCR units at SJGS. As of the effective date of the Legacy Rule, one CCRMU was identified at SJGS. SJGS is required, at a minimum, to conduct a two-part evaluation of historic and current CCRMUs with reporting due dates of February 9, 2027, and February 8, 2028 (based on the new final extension rule), with each report posted to a company website by the due date. At this time, PNM is still evaluating the financial impacts of this final regulation for Four Corners. Initial CCRMU site surveys and final site investigation reports are expected to be finalized by February 9, 2027. Based on the information available to the Company at this time, PNM cannot reasonably estimate the fair value of the entire CCRMU ARO. PNM cannot predict the outcome of the CCRMU site evaluations and investigations, or how these outcomes might affect the associated costs, which might have a material impact on PNM’s operations, financial position, or cash flows. In 2020, EPA published a proposed rule establishing a federal permitting program for the handling of CCR within the boundaries of Native American reservations and in states without their own federally authorized state programs. Permits for units within the boundaries of Native American reservations would be due 18 months after the effective date of the rule. EPA has not yet finalized the federal permitting program rule. On May 8, 2026, EPA published a notice reopening the comment period on the proposed federal CCR permit program. Comments were due July 29, 2026. EPA has coordinated with the affected permits for the three facilities with CCR disposal units located on Native American lands. PNM cannot predict the outcome of EPA’s rulemaking activity or the outcome of any related litigation, and whether or how such a ruling would affect operations at Four Corners. Separately, on July 13, 2026, EPA issued an advance notice of proposed rulemaking to solicit comments on a potential federal general permit option for CCR facilities. The comment period ended on October 13, 2026. EPA’s CCR rule does not cover mine placement of coal ash. In the preamble to its 2015 rule, EPA explained that the OSM and, as necessary, EPA would address the management of CCR in mine fills in a separate regulatory action, recognizing OSM’s expertise in this area. EPA’s decision to defer to OSM was based on a recommendation from the National Academy of Sciences (“NAS”), which was commissioned by Congress in 2006 to investigate the health, safety and environmental risks associated with the use of CCR for mine reclamation. The NRC report recommended that enforceable federal standards be established for the disposal of CCR in mine fills to ensure that states have specific authority and that states implement adequate safeguards. In 2007, OSM published an advance notice of proposed rulemaking on the placement of CCR at mine sites. In that notice, OSM explained its intent to develop the proposed regulations based on its existing authority under the Surface Mining Control and Reclamation Act. Since 2007, however, OSM has not taken any further action to advance this rulemaking. PNM cannot predict the outcome of OSM’s proposed rulemaking regarding CCR regulation, including mine placement of CCRs, or whether OSM’s actions will have a material impact on PNM’s operations, financial position, or cash flows. As noted above, SJGS did not operate any onsite CCR impoundments or landfills that are regulated under the 2015 CCR rule, and as of November 8, 2024, identified only one CCRMU that would potentially be regulated under the Legacy Rule. The CCR has since been removed from that unit and PNM will conduct the requisite site investigation reports. PNM would seek recovery from its retail customers of all CCR costs for jurisdictional assets that are ultimately incurred. Utilities that own or operate CCR disposal units, such as those at Four Corners, as indicated above, were required to collect sufficient groundwater sampling data to initiate a detection monitoring program. Four Corners completed the analysis for its CCR disposal units, which identified several units that needed corrective action. Four Corners continues to gather additional groundwater data and perform remedial evaluations and activities. At this time, PNM does not anticipate its share of the cost to complete these corrective actions to close the CCR disposal units, or to gather and perform remedial evaluations on groundwater at Four Corners, will have a significant impact on its operations, financial position, or cash flows. Other Commitments and Contingencies Coal Supply Four Corners APS purchases all of Four Corners’ coal requirements from NTEC, an entity owned by the Navajo Nation, under the Four Corners CSA that expires in 2031. The coal comes from reserves located within the Navajo Nation. The contract provides for pricing adjustments over its term based on economic indices and certain minimum payments that may be required if no deliveries of coal are taken. PNM’s share of the coal costs is being recovered through the FPPAC. See additional discussion of the Four Corners CSA in Note 17 of the Notes to Consolidated Financial Statements in the 2025 Annual Reports on Form 10-K. Coal Mine Reclamation As indicated under Coal Combustion Residuals Waste Disposal above, SJGS disposed of CCRs in the surface mine pits adjacent to the plant and Four Corners disposes of CCRs in ponds and dry storage areas. Under the terms of the SJGS CSA, PNM and the other SJGS owners are obligated to compensate WSJ LLC for all reclamation costs associated with the supply of coal from the San Juan mine. PNM and Westmoreland have entered into an agreement under which mine reclamation services for SJGS would be provided. In the third quarter of 2025, PNM and Westmoreland amended the mine reclamation services agreement to update the capital recovery charges due in each year from 2025 through 2028, which resulted in an increase in overall reclamation costs. As a result, as of September 30, 2025, there was an increase in the liabilities related to both the underground mine of $0.2 million and the surface mine of $0.2 million. PNM recorded the increase in the liability related to the underground mine as a regulatory asset and the increase related to the surface mine liability was recognized as a regulatory disallowance on the Condensed Consolidated Statements of Earnings for the three and nine months ended September 30, 2025. PNM’s estimate of the costs necessary to reclaim the mine that serves SJGS is subject to many assumptions, including the timing of reclamation, generally accepted practices at the time reclamation activities occur, and current inflation and discount rates. PNM cannot predict the ultimate cost to reclaim the mine that serves SJGS and would seek to recover all costs related to reclaiming the underground mine from its customers but could be exposed to additional loss related to surface mine reclamation. In connection with certain mining permits relating to the operation of the San Juan mine, Westmoreland was required to post reclamation bonds of $118.7 million with the NMMMD. In order to facilitate the posting of reclamation bonds by sureties on behalf of Westmoreland, TXNM entered into the WFB LOC Facility under which letters of credit aggregating $19.3 million are outstanding as of September 30, 2026. In 2025, APS provided an update to the cumulative MMBTU consumption for Four Corners for the purpose of allocating final mine reclamation costs. Based on the consumption outlook, PNM’s forecasted share of final reclamation costs was reduced from 9.755% to 9.096%. As a result, PNM recorded a decrease in the liability related to the surface mine of $0.9 million as a reduction in regulatory disallowance on the Condensed Consolidated Statements of Earnings for the three and nine months ended September 30, 2025. Based on the most recent estimates, PNM’s remaining payments as of September 30, 2026, for mine reclamation, in future dollars, are estimated to be $17.5 million for the surface mines at both SJGS and Four Corners and $63.1 million for the underground mine at SJGS. At September 30, 2026 and December 31, 2025, liabilities, in current dollars, of $9.3 million and $20.8 million for surface mine reclamation and $56.9 million and $55.2 million for underground mine reclamation were recorded in other deferred credits. The SJGS owners are parties to a reclamation trust funds agreement to provide financial assurance for post-term coal mine reclamation obligations. The trust funds agreement requires each owner to enter into an individual trust agreement with a financial institution as trustee, create an irrevocable reclamation trust, and meet year-end funding targets set by funding curves that are approved by the SJGS ownership. PNM began using its mine reclamation trust to pay for final mine reclamation costs in April 2023. Because the trust agreement requires meeting specific funding targets at year end, it may be necessary for PNM to make additional contributions to meet those targets. PNM contributed $7.0 million in 2025. Based on PNM’s reclamation trust fund balance at September 30, 2026, current forecasts, and current funding curve targets, PNM anticipates contributing $3.4 million in 2026 and anticipates making contributions of $0.4 million in 2027 and $4.7 million in 2028. Under the Four Corners CSA, PNM is required to fund its share of estimated final reclamation costs in annual installments into an irrevocable escrow account solely dedicated to the final reclamation cost of the surface mine at Four Corners. PNM did not make any contributions in 2025 and anticipates contributing $0.5 million per year for 2026, 2027 and 2028. PNM recovers from retail customers’ reclamation costs associated with the underground mine. However, the NMPRC capped the amount collected from retail customers for final reclamation of the surface mines at $100.0 million for both SJGS and Four Corners. If future estimates increase the liability for surface mine reclamation, the excess would be expensed at that time. The impacts of changes in New Mexico state law as a result of the enactment of the ETA and regulatory determinations made by the NMPRC may also affect PNM’s financial position, results of operations, and cash flows. PNM is currently unable to determine the outcome of these matters. SJGS Decommissioning In 2021, the San Juan County Commission approved the Coal-Fired Electricity Generating Facility Demolition and Remediation Ordinance (“Ordinance 121”), requiring the full demolition of SJGS upon its complete and permanent closure. Ordinance 121 required the SJGS owners to submit a proposed demolition and remediation plan no later than three months after SJGS was retired. PNM and the other SJGS entered into the San Juan Decommissioning and Trust Funds Agreement, which requires PNM to fund its ownership share of final decommissioning costs into an irrevocable trust. Under the agreement, PNM is required to make funding contributions of which the amount and timing are subject to revised decommissioning cost studies and agreement among the SJGS owners. PNM began using its decommissioning trust to pay for demolition and decommissioning costs in October 2023. PNM has posted a surety bond in the amount of $46.0 million in connection with certain environmental decommissioning obligations and must maintain the bond or other financial assurance until those obligations are satisfied. The surety bond only represents a liability if the SJGS owners fail to deliver on its contractual liability. PNM records its share of the SJGS decommissioning obligation as an ARO on its Condensed Consolidated Balance Sheets. Studies on the decommissioning costs of SJGS are performed periodically and revisions to the ARO liability are recorded. On July 29, 2025, PNM received a letter from the NMED indicating that the NMED designated PNM as a responsible party and requiring a Stage 1 Abatement Plan (“S1AP”) proposal for SJGS for groundwater and soil contamination associated with former operations at SJGS. On November 26, 2025, PNM submitted the S1AP to NMED that was approved on February 9, 2026. The S1AP estimates site investigation and monitoring to be completed by the first quarter of 2027. PNM is currently conducting site investigations, groundwater sampling, and monitoring detailed in the S1AP. PVNGS Liability and Insurance Matters Public liability for incidents at nuclear power plants is governed by the Price-Anderson Nuclear Industries Indemnity Act, which limits the liability of nuclear reactor owners to the amount of insurance available from both commercial sources and an industry-wide retrospective payment plan. The insurance limit is subject to an adjustment every five years based upon the aggregate percentage change in the Consumer Price Index. The most recent adjustment took effect on January 1, 2024. As of that date, in accordance with this act, the PVNGS participants are insured against public liability exposure for a nuclear incident up to $16.4 billion per occurrence. PVNGS maintains the maximum available nuclear liability insurance in the amount of $500 million, which is provided by American Nuclear Insurers. The remaining $15.9 billion is provided through a mandatory industry-wide retrospective assessment program. If losses at any nuclear power plant covered by the program exceed the accumulated funds, PNM could be assessed retrospective premium adjustments. The maximum retrospective premium per reactor under the program for each nuclear liability incident is $165.9 million, subject to a maximum annual premium of $24.7 million per incident. Based on PNM’s ownership interest in the three units, PNM’s maximum retrospective premium per incident for all three units is $12.1 million, with a maximum annual payment limitation of $1.8 million, to be adjusted periodically for inflation. The PVNGS participants maintain insurance for damage to and decontamination of property at PVNGS in the aggregate amount of $2.8 billion, a substantial portion of which must first be applied to stabilization and decontamination. These coverages are provided by Nuclear Electric Insurance Limited (“NEIL”). If NEIL’s losses in any policy year exceed accumulated funds, PNM is subject to retrospective premium adjustments of $5.0 million. The insurance coverage discussed in this and the previous paragraph are subject to certain policy conditions, sublimits, and exclusions.

Counsel for TXNM has received a number of demand letters from certain law firms on behalf of individuals who are purported TXNM shareholders, accompanied by draft complaints naming TXNM and its directors as defendants and alleging that TXNM’s preliminary proxy statement with respect to the Merger omitted or misrepresented certain material information. Such draft complaints include a request for injunctive relief with respect to the TXNM shareholder vote to approve, and the closing of, the Merger, as well as other remedies, including counsel fees. In August 2025, reported shareholders filed complaints in New York state court alleging disclosure violations and seeking injunctive relief. TXNM believes that the allegations set forth in the demand letters, draft complaints, and complaints are without merit and will defend against such actions vigorously.

With respect to some of the items listed below, the Company has determined that a loss is not probable or that, to the extent probable, cannot be reasonably estimated. In some cases, the Company is not able to predict with any degree of certainty the range of possible loss that could be incurred. The Company assesses legal and regulatory matters based on current information and makes judgments concerning their potential outcome, giving due consideration to the nature of the claim, the amount and nature of any damages sought, and the probability of success. Such judgments are made with the understanding that the outcome of any litigation, investigation, or other legal proceeding is inherently uncertain. The Company records liabilities for matters where it is probable a loss has been incurred, and the amount of loss is reasonably estimatable. The actual outcomes of the items listed below could ultimately differ from the judgments made and the differences could be material. The Company cannot make any assurances that the amount of reserves or potential insurance coverage will be sufficient to cover the cash obligations that might be incurred as a result of litigation or regulatory proceedings. Except as otherwise disclosed, the Company does not expect that any known lawsuits, environmental costs, or commitments will have a material effect on its financial condition, results of operations, or cash flows.

Nuclear power plant operators are required to enter into spent fuel disposal contracts with the DOE that require the DOE to accept and dispose of all spent nuclear fuel and other high-level radioactive wastes generated by domestic power reactors. Although the Nuclear Waste Policy Act required the DOE to develop a permanent repository for the storage and disposal of spent nuclear fuel by 1998, the DOE announced that it would not be able to open the repository by 1998 and sought to excuse its performance of these requirements. In November 1997, the DC Circuit issued a decision preventing the DOE from excusing its own delay but refused to order the DOE to begin accepting spent nuclear fuel. Based on this decision and the DOE’s delay, a number of utilities, including APS (on behalf of itself and the other PVNGS owners, including PNM), filed damages actions against the DOE in the Court of Federal Claims. The lawsuits filed by APS alleged that damages were incurred due to DOE’s continuing failure to remove spent nuclear fuel and high-level waste from PVNGS. APS and the DOE entered into a settlement agreement, subsequently extended, that established a process for the payment of claims for costs incurred through December 31, 2025. Under the settlement agreement, APS must submit claims annually for payment of allowable costs. APS is currently in the process of extending the settlement to cover costs paid through December 31, 2028. PNM records estimated claims on a quarterly basis. The benefit from the claims is passed through to customers under the FPPAC.

PVNGS has sufficient capacity at its on-site Independent Spent Fuel Storage Installation (“ISFSI”) to store all of the nuclear fuel that will be irradiated during the initial operating license period, which ends in December 2027. Additionally, PVNGS has sufficient capacity at its on-site ISFSI to store a portion of the fuel that will be irradiated during the period of extended operation, which ends in November 2047. If uncertainties regarding the U.S. Government’s obligation to accept and store spent fuel are not favorably resolved, APS will evaluate alternative storage solutions that may obviate the need to expand the ISFSI to accommodate all of the fuel that will be irradiated during the period of extended operation.

undepreciated investments and decommissioning costs related to qualifying EGUs that the NMPRC has required be removed from retail jurisdictional rates, provided replacement resources to be included in retail rates have lower or zero-carbon emissions. The ETA requires the NMPRC to review and approve utilities’ annual renewable portfolio plans to ensure compliance with the RPS. Also pursuant to the ETA, the NM Environmental Improvement Board adopted standards of performance that limit CO2 emissions to no more than 1,100 lbs. per MWh beginning January 1, 2023, for new and existing coal-fired EGUs with original installed capacities exceeding 300 MW.

The ETA provides for a transition from fossil-fuel generation resources to renewable and other carbon-free resources through certain provisions relating to the abandonment of coal-fired generating facilities. These provisions include the use of energy transition bonds to finance certain costs of abandoning coal-fired facilities that are retired prior to January 1, 2023, for facilities operated by a “qualifying utility,” or prior to January 1, 2032, for facilities that are not operated by a qualifying utility. The amount of energy transition bonds that can be issued to recover abandonment costs is limited to the lesser of $375.0 million or 150% of the undepreciated investment of the facility as of the abandonment date. Proceeds provided by energy transition bonds must be used only for purposes related to providing utility service to customers and to pay energy transition costs (as defined by the ETA). These costs may include plant decommissioning and coal mine reclamation costs provided those costs have not previously been recovered from customers or disallowed by the NMPRC or by a court order. Proceeds from energy transition bonds may also be used to fund severances for employees of the retired facility and related coal mine and to promote economic development, education and job training in areas impacted by the retirement of the coal-fired facilities. Energy transition bonds must be issued under a NMPRC-approved financing order, are secured by “energy transition property,” are non-recourse to the issuing utility, and are repaid by a non-bypassable charge paid by all customers of the issuing utility. These customer charges are subject to an adjustment mechanism designed to provide for timely and complete payment of principal and interest due under the energy transition bonds.

The ETA also provides that utilities must obtain NMPRC approval of competitively procured replacement resources that shall be evaluated based on their cost, economic development opportunity, ability to provide jobs with comparable pay and benefits to those lost upon retirement of the facility, and that do not exceed emissions thresholds specified in the ETA. In determining whether to approve replacement resources, the NMPRC must give preference to resources with the least environmental impacts, those with higher ratios of capital costs to fuel costs, and those located in the school district of the abandoned facility. The ETA also provides for the procurement of energy storage facilities and gives utilities discretion to maintain, control, and operate these systems to ensure reliable and efficient service.

In April 2026, New Mexico became the fourth state to adopt a clean fuel standard by launching the CTFP administered by NMED. The primary goal of the CTFP is to reduce overall climate pollution from transportation fuel used in New Mexico by establishing annual statewide CI standards for transportation fuel, allocating credits and calculating deficits for importers, producers or dispensers of transportation fuel in New Mexico based on whether their fuel is below or above the CI standards. The CTFP also creates a marketplace where CI standards may be met by generating credits from importing or producing low-carbon fuel, using banked credits, or acquiring credits. PNM has opted into the CTFP as a low-carbon fuel producer to participate in this marketplace by generating credits and selling credits. PNM expects the first batch of credits to be produced from residential EV charging to be available towards the end of 2026 and sold in the marketplace within the first half of 2027. PNM will use the proceeds from the sale of the credits to further support transportation electrification through the current TEP rider.

Pursuant to the CAA, states are required to establish goals for improving visibility in national parks and wilderness areas (also known as Class I areas) and to develop long-term strategies for reducing emissions of air pollutants that cause visibility impairment in their own states and for preventing degradation in other states. States must establish a series of interim goals to ensure continued progress by adopting a new SIP every ten years. In the first SIP planning period, states were required to conduct Best Available Retrofit Technology determinations for certain covered facilities, including utility boilers, built between 1962 and 1977 that have the potential to emit more than 250 tons per year of visibility impairing pollution. For all

SIPs for the second planning period were due in July 2021, which deadline NMED was unable to meet. During NMED’s preparation of the SIP for the second compliance period, PNM was notified that a regional haze four-factor analysis for SJGS was not required since PNM retired its share of SJGS in 2022. NMED petitioned the NM Environmental Improvement Board to adopt a proposed SIP and submitted a final revised plan to the NM Environmental Improvement Board in March 2025. PNM submitted comments on the proposed SIP in response to a request for comments by NMED. No PNM generating stations were identified as reasonable progress units under the adopted SIP indicating that no additional emissions reductions measures may be necessary at this time. On March 11, 2026, the NMED submitted a SIP revision for the second planning period requesting approval by EPA.

On March 12, 2025, as part of EPA’s list of 31 deregulatory actions, EPA announced it would restructure the Regional Haze Program. On October 2, 2025, EPA published an advanced notice of proposed rulemaking to solicit information from the public to help develop regulatory changes on the implementation and structure of the Regional Haze Rule (“RHR”). The advanced notice itself does not impose any requirements but requests input on how EPA can revise the RHR to streamline regulatory requirements impacting states’ visibility improvement obligations. Comments were due December 1, 2025. On December 31, 2025, EPA extended the deadline for the third planning period SIPs to July 31, 2031. In February 2026, EPA updated its guidance to ensure that the SIPs account for grid reliability and strategies to prevent premature plant closures.

In 2015, EPA established standards to limit CO2 emissions from power plants, including (1) Carbon Pollution Standards for new, modified, and reconstructed power plants; and (2) the Clean Power Plan for existing power plants. Challengers successfully petitioned the U.S. Supreme Court for a stay of the Clean Power Plan. In 2019, EPA repealed the Clean Power Plan, promulgated the ACE Rule, and revised the implementing regulations for all emission guidelines. The ACE Rule was also challenged, and on January 19, 2021, the DC Circuit issued an opinion in American Lung Association and American Public Health Association v. EPA, et al., vacating the ACE Rule.

Numerous parties sought review by the U.S. Supreme Court, and on June 30, 2022, the U.S. Supreme Court held that the “generation shifting” approach in the Clean Power Plan exceeded the powers granted to EPA by Congress. Of broader significance in administrative law, the Court’s opinion expressly invoked the “major question” doctrine, which requires rules involving issues of “vast economic or political significance” to be supported by clear statutory authorization. In cases where there is no clear statement of authority, courts need not defer to the agency’s statutory interpretation on “major questions.” The decision sets legal precedent for future rulemakings by EPA and other federal regulatory agencies whereby the agencies’ authority may be limited based upon similar reasoning.

In 2024, EPA adopted regulatory actions under CAA Sections 111(b) and (d) to replace the Clean Power Plan and the ACE Rule. The final rules included revised new source performance standards under CAA Section 111(b) for all new natural gas-fired combustion turbines and emission guidelines under CAA Section 111(d) requiring states to develop standards of performance for GHG emissions from existing fossil-fuel-fired electric steam generating units. In the final rules, EPA determined that the standards for existing coal- or gas-fired steam generating units must be based on the use of either CCS (long-term), natural gas co-firing (medium-term), or exempt from the rule via early retirement. The standards for new combustion turbines must be based on CCS (base load), efficient simple cycle design (intermediate load), or lower-emitting fuels (low load). Over a dozen states, several industry groups and some power companies and labor unions filed challenges to the rule at the DC Circuit.

On January 20, 2025, President Trump issued several executive orders directing his Administration to review all agency actions and suspend, revise, or rescind those identified as imposing an undue burden on domestic energy resources. On March 12, 2025, as part of EPA’s reconsideration of 31 environmental regulations, EPA announced it will reconsider the previous Administration’s regulations on GHG standards and guidelines for power plants. On June 17, 2025, EPA published a proposed rule in the Federal Register with two alternatives to repeal or revise the GHG emission standards for EGUs. EPA primarily proposed to find that GHG emissions from fossil fuel-fired power plants “do not contribute significantly to dangerous air pollution” under the meaning of CAA Section 111, which would preclude EPA from regulating GHG emissions from those plants. As a result, EPA proposed to repeal all GHG standards for the power sector promulgated under CAA Section 111 in

On September 14, 2026, EPA published a notice of its decision to finalize the alternative proposal to partially repeal the 2024 standards, including the CCS-based standards and all of the standards for existing steam generating units. That final rule is expected to be effective on November 16, 2026, and it has been challenged by numerous parties in the DC Circuit. At the same time EPA issued the notice of a final partial repeal of the 2024 standards, EPA also issued a supplemental proposal on the subject of whether EPA may regulate GHG emissions from the power sector under CAA Section 111 at all, similar to the primary proposal issued in 2025 but under a different legal theory focused on whether the emissions constitute “air pollution” anticipated to “endanger human health and welfare.” Comments on that supplemental proposal are due on November 2, 2026. If finalized as proposed, the supplemental proposal would result in the repeal of all of the remaining GHG standards from EPA’s 2015 and 2024 rulemakings, including the efficiency standards for natural gas-fired combustion turbines and the partial CCS requirements for new steam generating units.

In 2021, then President Biden signed an extensive executive order aimed at addressing a wide range of issues, including establishing climate change concerns as an essential element of U.S. foreign and security policy, identifying a process to determine the U.S. INDC under the Paris Agreement, and establishing a Special Presidential Envoy for Climate that would sit on the National Security Council. On April 22, 2021, at the Earth Day Summit, as part of the U.S.’s re-entry into the Paris Agreement, then President Biden unveiled the goal to cut U.S. emissions by 50% - 52% from 2005 levels by 2030. The 2030 emissions goal supported other climate goals which included a carbon pollution-free power sector by 2035 and a net-zero emissions economy by no later than 2050. In an executive order issued on January 20, 2025, President Trump ordered his Administration to withdraw the U.S. from the Paris Agreement and from any agreement, pact, accord, or similar commitment made under the United Nations Framework Convention on Climate Change.

On August 1, 2025, EPA published a proposal to rescind the 2009 final rule commonly known as the Endangerment Finding. In the Endangerment Finding, EPA found that current and projected atmospheric concentrations of the well-mixed combination of six GHGs threaten public health and welfare, and that the combined emissions of these GHGs from new motor vehicles and engines contribute to the GHG pollution that threatens public health and welfare. On February 12, 2026, the rule was finalized as proposed, repealing all GHG emission standards for certain vehicles and engines promulgated on the basis of the Endangerment Finding. While the Endangerment Finding did not directly impose any requirements on EGUs, EPA cited the Endangerment Finding as a basis for its authority to regulate GHG emissions from EGUs under CAA Section 111, and EPA has identified that reliance on the Endangerment Finding as a basis for its supplemental proposal to find that CAA Section 111 does not authorize EPA to regulate GHG emissions from the power sector.

SO2 Standard – In 2019, EPA announced its final decision to retain, without changes, the primary health-based NAAQS for SO2. Specifically, EPA retained the current 1-hour standard for SO2, which is 75 parts per billion, based on the 3-year average of the 99th percentile of daily maximum 1-hour SO2 concentrations. In 2021, EPA published in the Federal Register the initial air quality designations for all remaining areas not yet designated under the 2010 SO2 Primary NAAQS. All areas of New Mexico have been designated attainment/unclassifiable through four rounds of designations by EPA.

come under increasing pressure to reduce emissions of NOx and volatile organic compounds since these are the pollutants that form ground-level ozone. During 2017 and 2018, EPA released rules establishing area designations for ozone. In those rules, San Juan County, New Mexico, where Four Corners is located, is designated as attainment/unclassifiable and only a small area in Doña Ana County, New Mexico is designated as marginal non-attainment. Although Afton Generating Station is located in Doña Ana County, it is not located within the small area designated as non-attainment for the 2015 ozone standard.

PNM does not believe there will be material impacts to its facilities because of the non-attainment designation of the small area within Doña Ana County. Until EPA approves attainment designations for the Navajo Nation and releases a proposal to implement the revised ozone NAAQS, PNM is unable to predict what impact the adoption of these standards may have on Four Corners. On July 13, 2020, EPA proposed to retain the existing ozone NAAQS based on a review of the full body of currently available scientific evidence and exposure/risk information, but on August 21, 2023, EPA announced an entirely new review of the ozone standard. PNM cannot predict the outcome of this matter.

In 2019, EPA issued findings that several states, including New Mexico, had failed to submit interstate transport SIPs for the 2015 8-hour ozone NAAQS, triggering an obligation for EPA to issue a FIP within two years. In response, NMED submitted a Good Neighbor SIP on July 27, 2021, that demonstrates that there are no significant contributions from New Mexico to downwind problems in meeting the federal ozone standard. On March 15, 2023, EPA Administrator Regan signed a final action imposing a FIP on multiple states but did not include a FIP for New Mexico because the most updated modeling available at the time of the proposal confirmed the state did not contribute to downwind ozone nonattainment or maintenance areas. However, the updated modeling EPA used in the final rule indicated that New Mexico may be significantly contributing to one or more non-attainment or maintenance areas. In light of that modeling result, on February 16, 2024, the EPA published a proposed rule partially disapproving the SIPs for New Mexico and four other states (Arizona, Iowa, Kansas, and Tennessee) and expanding the Good Neighbor FIP to apply to these states. The FIP aspect of the proposed rule would have required fossil fuel-fired power plants in these five states to participate in an allowance-based ozone season NOx emissions trading program beginning in 2025, but the outgoing Biden Administration did not finalize the rule. On March 10, 2025, in the DC Circuit, the EPA filed a motion for voluntary remand of its ozone interstate transport FIP for the 2015 ozone NAAQS to reconsider the rule and had anticipated completing a new rulemaking by Fall 2026. In addition, EPA has now reconsidered the policies underlying its Good Neighbor rule, and, on January 30, 2026, EPA issued a proposed rule to approve New Mexico’s SIP submission because it will not contribute significantly to nonattainment or interfere with maintenance of the 2015 8-hour ozone NAAQS in any other state. If finalized, the EPA will withdraw the prior proposed partial SIP disapproval.

PM Standard – In 2023, EPA published, in the Federal Register, a proposal to lower the annual fine PM standard to between 9-10 µg/m3 but retain the rest of its PM standards, including the current daily fine PM standard, the daily coarse PM standard, and the secondary PM standards. The final rule was published on March 6, 2024, lowering the primary annual PM 2.5 NAAQS to 9 ug/m3, and became effective May 6, 2024. States will have until March 2032 to attain compliance with the new standard for any areas designated as nonattainment. This implementation process also applies to the Albuquerque-Bernalillo County Environmental Health Department who may combine efforts with NMED. However, even before any designations are made, the new standard is effective for conducting required modeling for permit applications and revisions. The lower standard is expected to result in new nonattainment areas throughout the country and could prompt additional PM control requirements, but PNM cannot predict the impacts of the outcome of future rulemaking. The PM standard was challenged in the D.C. Circuit, and, following the change in administration, EPA filed a motion for voluntary vacatur of the rule, but the court denied that motion and upheld the new standard on June 26, 2026. The Northern District of California has ordered EPA to promulgate final designations for all areas of the country no later than February 6, 2027.

To minimize impingement mortality, the rule provides operators of facilities, such as Four Corners, seven options for meeting Best Technology Available (“BTA”) standards for reducing impingement. The permitting authority must establish the BTA for entrainment on a site-specific basis, taking into consideration an array of factors, including endangered species and social costs and benefits. Affected sources must submit source water baseline characterization data to the permitting authority to assist in the BTA determination. Compliance deadlines under the rule are tied to permit renewals, including any subject to a schedule of compliance established by the permitting authority in the permit itself.

In 2018, several environmental groups sued EPA Region IX in the U.S. Court of Appeals for the Ninth Circuit over EPA’s failure to timely reissue the Four Corners NPDES permit. The petitioners asked the court to issue a writ of mandamus compelling EPA Region IX to take final action on the pending NPDES permit by a reasonable date. EPA subsequently reissued the NPDES permit. The permit did not contain conditions related to the cooling water intake structure rule, because EPA determined that the facility had achieved BTA for both impingement and entrainment by operating a closed-cycle recirculation system. Several environmental groups filed a petition for review with EPA’s Environmental Appeals Board (“EAB”) concerning the reissued permit. The environmental groups alleged that the permit was reissued in contravention of the Clean Water Act and did not contain limits or conditions required by EPA’s ELG applicable to Four Corners or EPA’s cooling water intake structures rule, among others. EPA withdrew the Four Corners NPDES permit in order to examine the issues raised by the environmental groups and then issued an updated NPDES permit in 2019. The permit was once again appealed to the EAB and was stayed before the effective date, but the EAB issued an order denying the petition for review on September 30, 2020. Thereafter, the Regional Administrator of the EPA signed a notice of final permit decision, and the NPDES permit was issued on November 9, 2020. The permit became effective December 1, 2020. On January 22, 2021, the environmental groups filed a petition for review of the EAB’s decision with the U.S. Court of Appeals for the Ninth Circuit. The September 2019 permit remained in effect pending the outcome of this appeal. On March 21, 2022, EPA provided notice in the Federal Register of a proposed settlement agreement with the environmental groups. The parties subsequently executed the settlement agreement as of May 2, 2022. Under the settlement, the lawsuit was administratively closed through September 6, 2023, during which time a third-party consultant spent 12 months sampling discharges from Four Corners and EPA spent three months completing an analysis. On December 1, 2023, EPA issued a modification, effective December 31, 2023, to the NPDES permit that had been issued on November 9, 2020. The modification applies to permit elements related to effluent discharge. PNM cannot predict whether the analysis required to be performed by EPA under the settlement agreement will result in further changes to the NPDES permit but does not anticipate that it will have a material impact on PNM’s financial position, results of operations, or cash flows.

In 2013, EPA published proposed revised wastewater ELG establishing technology-based wastewater discharge limitations for fossil fuel-fired electric power plants. EPA signed the final Steam Electric ELG rule in 2015. The final rule, which became effective on January 4, 2016, phased in the new, more stringent requirements in the form of effluent limits for arsenic, mercury, selenium, and nitrogen for wastewater discharged from wet scrubber systems and zero discharge of pollutants in ash transport water that must be incorporated into plants’ NPDES permits. The 2015 rule required each plant to comply between 2018 and 2023 depending on when it needed a new or revised NPDES permit.

The Steam Electric ELG rule was challenged in the U.S. Court of Appeals for the Fifth Circuit by numerous parties. In 2017, EPA signed a notice indicating its intent to reconsider portions of the rule, and the Fifth Circuit issued an order severing the issues under reconsideration and holding the case in abeyance as to those issues. However, the court allowed challenges to other portions of the rule to proceed. In 2019, the Fifth Circuit granted those challenges and issued an opinion vacating several portions of the rule, specifically those related to legacy wastewater and leachate, for which the court deemed the standards selected by EPA to be arbitrary and capricious.

In 2017, EPA published a final rule for postponement of certain compliance dates. The rule postponed the earliest date on which compliance with the ELG for regulated waste streams would be required from November 1, 2018 until November 1, 2020. In 2019, EPA published a proposed rule revising the original ELG while maintaining the compliance dates. In 2020, EPA published in the Federal Register the final Steam Electric ELG and Standards for the Steam Electric Power Generating Point Source Category, revising the final 2015 guidelines for both flue gas desulfurization wastewater and bottom ash transport water. The 2020 rule required compliance with new limits as soon as possible on or after October 13, 2021, but no later than December 31, 2025.

In 2021, EPA published notice that it would undertake a supplemental rulemaking to revise the ELG after completing its review of the rules reconsidered in 2020. As part of this process, EPA committed to determine whether more stringent limitations and standards would be appropriate. On March 29, 2023, EPA published the proposed ELG Rule in the Federal Register. The proposed rule included stricter limitations for wastewater discharges for coal-fired facilities but allowed for flexibilities for those coal-powered facilities that would decommission or repower by December 31, 2028, to December 31, 2032.

wastewater at existing sources, as well as combustion residual leachate at new and existing sources. The 2024 rule was challenged in the U.S. Court of Appeals for the Eighth Circuit, but the court denied motions for a stay, so the rule remains in effect. On March 12, 2025, EPA announced it would reconsider the ELGs for the steam electric power generating industry. On October 2, 2025, EPA published proposed and direct final rules for extension of deadlines and other provisions. Comments were due November 3, 2025. On November 28, 2025, EPA withdrew the direct final rule due to adverse comments and on December 31, 2025, published a final rule revising various deadlines and other provisions in the 2024 rule. On March 9, 2026, EPA sent a proposed rule to Office of Management and Budget reconsidering the technology-based effluent limitations and standards promulgated in 2024. On May 18, 2026, EPA published its proposed rule revising ELGs for unmanaged combustion residual leachate. Comments were due June 17, 2026. The final rule is expected to be published in March 2027.

PNM and NMED are parties to agreements under which PNM has installed a remediation system to treat water from a City of Santa Fe municipal supply well and an extraction well to address gasoline contamination in the groundwater at the site of PNM’s former Santa Fe Generating Station and service center. A 2008 NMED site inspection report states that neither the source nor extent of contamination at the site has been determined and that the source may not be the former Santa Fe Generating Station. During 2013 and 2014, PNM and NMED collected additional samples that showed elevated concentrations of nitrate and volatile organic compounds in some of the monitoring wells at the site. In addition, one monitoring well contained free-phase hydrocarbon products. PNM collected a sample of the product for “fingerprint” analysis. The results of this analysis indicated the product was a mixture of older and newer fuels. The presence of newer fuels in the sample suggests the hydrocarbon product likely originated from off-site sources. In 2015, PNM and NMED entered into a memorandum of understanding to address changing groundwater conditions at the site under which PNM agreed to continue hydrocarbon investigation under the supervision of NMED. Qualified costs are eligible for payment through the New Mexico Corrective Action Fund (“CAF”), which is administered by the NMED Petroleum Storage Tank Bureau. In 2019, PNM received notice from NMED that an abatement plan for the site is required to address concentrations of previously identified compounds, unrelated to those discussed above, found in the groundwater. NMED approved PNM’s abatement plan proposal, which covers ongoing field work monitoring and reporting.

The City of Santa Fe has stopped operating its well at the site, which is needed for PNM’s groundwater remediation system to operate. As a result, PNM has stopped performing remediation activities at the site. However, PNM’s monitoring and other abatement activities at the site are ongoing and will continue until the groundwater meets applicable federal and state standards or until NMED determines that remediation is not required, whichever is earlier. PNM is also in communications with the City of Santa Fe to determine when operations at the site might resume. PNM is not able to assess the duration of this project or estimate the impact on its obligations if PNM is required to resume groundwater remediation activities at the site. PNM is unable to predict the outcome of these matters.

CCRs consisting of fly ash, bottom ash, and gypsum generated from coal combustion and emission control equipment at SJGS have been disposed of in the surface mine pits adjacent to the plant. SJGS does not operate any onsite CCR impoundments or landfills. The NMMMD currently regulates mine reclamation activities at the San Juan mine, including placement of CCRs in the surface mine pits, with federal oversight by the OSM. APS disposes of CCRs in onsite ponds and dry storage areas at Four Corners. Ash management at Four Corners is regulated by EPA and the New Mexico State Engineer’s Office.

EPA’s 2015 coal ash rule included a non-hazardous waste determination for coal ash and sets minimum criteria for existing and new CCR landfills and surface impoundments. In 2016, the Water Infrastructure Improvements for the Nation Act (the “WIIN Act”) was signed into law to address critical water infrastructure needs in the U.S. and contained a number of provisions related to CCRs. Among other things, the WIIN Act allowed, but did not require, states to develop and submit CCR permit programs for EPA approval, provided flexibility for states to incorporate EPA’s 2015 rule for CCRs or develop other criteria that are at least as protective as EPA’s rule, and required EPA to approve state permit programs within 180 days of submission by the state. Because states are not required to implement their own CCR permit programs, EPA was required to develop a federal permit program in states that chose not to implement a program, subject to congressional funding. Until state or federal permit programs are in effect, the 2015 rule continues to be self-implementing in nature, subject to enforcement by EPA or citizen groups. For facilities located within the boundaries of Native American reservations, such as the Navajo Nation where Four Corners is located, EPA is required to develop a federal permit program regardless of appropriated funds.

In 2018, EPA published a rule that constitutes “Phase One, Part One” of its ongoing reconsideration and revision of the 2015 CCR rule. The final Phase One, Part One rule extended the deadline to allow EGUs with unlined impoundments or that fail to meet the uppermost aquifer requirement to continue to receive coal ash until October 31, 2020, which was again extended by subsequent amendments. The rule also authorized a “Participating State Director” or EPA to approve suspension of groundwater monitoring requirements and to issue certifications related to the location restrictions, design criteria, groundwater monitoring, remedy selection and implementation. The rule also modified groundwater protection standards for certain constituents, which include cobalt, molybdenum, lithium, and lead without a maximum contamination level.

Since its Phase Two proposal, EPA has finalized three other rules addressing various CCR rule provisions. In 2020, EPA promulgated its proposed Holistic Approach to Closure Part A (“Part A”), which set forth a new deadline of April 11, 2021, for companies to initiate closure of unlined CCR impoundments. In accordance with the DC Circuit’s vacatur of portions of the 2015 CCR Rule, Part A also changed the classification of compacted soil-lined or clay-lined surface impoundments from “lined” to “unlined”, triggering closure or retrofit requirements for those impoundments. In addition, Part A delineated a process for owners/operators to submit requests for alternative closure deadlines.

EPA also issued the Holistic Approach to Closure Part B (“Part B”) in 2020, which delineated the process for owners/operators to submit alternate liner demonstrations for clay-lined surface impoundments that could otherwise meet applicable requirements. This rule did not include beneficial use of CCR for closure, which EPA explained would be addressed in subsequent rulemaking actions. On May 18, 2023, EPA published a proposed rule establishing the regulatory requirements for inactive surface impoundments at inactive facilities and a new category of regulated unit called a CCR management unit (“CCRMU”), including groundwater monitoring, corrective action, closure, and post-closure care requirements for all CCR management units (regardless of how or when that CCR was placed), and several technical corrections to the existing regulations. Comments on the proposed rule were due July 17, 2023.

On May 8, 2024, EPA published a final rule that extended federal CCR regulatory requirements to (1) inactive CCR surface impoundments at inactive utilities and (2) CCRMU, including CCR impoundments and landfills that closed prior to the effective date of the 2015 CCR rule, inactive CCR landfills, and other areas where CCR was managed directly on the land (“Legacy Rule”). The Legacy Rule became effective on November 8, 2024. EPA included deferral options for smaller CCRMU containing between one and 1,000 tons of CCR, CCRMU located beneath critical infrastructure or large buildings or structures vital to the continuation of current site activities, and CCRMU that closed prior to the effective date of the new rule (subject to certain eligibility conditions). EPA also codified the controversial definitions of infiltration and liquids that were litigated in the DC Circuit. Six petitions for review of the Legacy Rule were filed and were consolidated into one case by the DC Circuit. The Utility Solid Waste Activities Group, of which TXNM is a member, is a petitioner jointly with the National Rural Electric Cooperative Association, and American Public Power Association. The U.S. Supreme Court denied a requested stay of the rule by East Kentucky Power Cooperative. The DC Circuit agreed to hold the case in abeyance pending the outcome of EPA’s reconsideration of the Legacy Rule, with status reports due on March 16, 2026, and at 90-day intervals thereafter. On July 22, 2025, EPA published a final rule and companion proposal revising the compliance deadlines for CCRMU requirements under the Legacy Rule. In September 2025, EPA withdrew the direct final rule due to adverse comments but subsequently issued a final extension rule on February 6, 2026, delaying the deadline to complete the “Facility Evaluation Report Part 1” until February 9, 2027, and extending all subsequent deadlines, as well. The final extension rule was published in the Federal

At this time, PNM is still evaluating the financial impacts of this final regulation for Four Corners. Initial CCRMU site surveys and final site investigation reports are expected to be finalized by February 9, 2027. Based on the information available to the Company at this time, PNM cannot reasonably estimate the fair value of the entire CCRMU ARO. PNM cannot predict the outcome of the CCRMU site evaluations and investigations, or how these outcomes might affect the associated costs, which might have a material impact on PNM’s operations, financial position, or cash flows.

In 2020, EPA published a proposed rule establishing a federal permitting program for the handling of CCR within the boundaries of Native American reservations and in states without their own federally authorized state programs. Permits for units within the boundaries of Native American reservations would be due 18 months after the effective date of the rule. EPA has not yet finalized the federal permitting program rule. On May 8, 2026, EPA published a notice reopening the comment period on the proposed federal CCR permit program. Comments were due July 29, 2026. EPA has coordinated with the affected permits for the three facilities with CCR disposal units located on Native American lands. PNM cannot predict the outcome of EPA’s rulemaking activity or the outcome of any related litigation, and whether or how such a ruling would affect operations at Four Corners. Separately, on July 13, 2026, EPA issued an advance notice of proposed rulemaking to solicit comments on a potential federal general permit option for CCR facilities. The comment period ended on October 13, 2026.

EPA’s CCR rule does not cover mine placement of coal ash. In the preamble to its 2015 rule, EPA explained that the OSM and, as necessary, EPA would address the management of CCR in mine fills in a separate regulatory action, recognizing OSM’s expertise in this area. EPA’s decision to defer to OSM was based on a recommendation from the National Academy of Sciences (“NAS”), which was commissioned by Congress in 2006 to investigate the health, safety and environmental risks associated with the use of CCR for mine reclamation. The NRC report recommended that enforceable federal standards be established for the disposal of CCR in mine fills to ensure that states have specific authority and that states implement adequate safeguards. In 2007, OSM published an advance notice of proposed rulemaking on the placement of CCR at mine sites. In that notice, OSM explained its intent to develop the proposed regulations based on its existing authority under the Surface Mining Control and Reclamation Act. Since 2007, however, OSM has not taken any further action to advance this rulemaking. PNM cannot predict the outcome of OSM’s proposed rulemaking regarding CCR regulation, including mine placement of CCRs, or whether OSM’s actions will have a material impact on PNM’s operations, financial position, or cash flows.

Utilities that own or operate CCR disposal units, such as those at Four Corners, as indicated above, were required to collect sufficient groundwater sampling data to initiate a detection monitoring program. Four Corners completed the analysis for its CCR disposal units, which identified several units that needed corrective action. Four Corners continues to gather additional groundwater data and perform remedial evaluations and activities. At this time, PNM does not anticipate its share of the cost to complete these corrective actions to close the CCR disposal units, or to gather and perform remedial evaluations on groundwater at Four Corners, will have a significant impact on its operations, financial position, or cash flows.

In the third quarter of 2025, PNM and Westmoreland amended the mine reclamation services agreement to update the capital recovery charges due in each year from 2025 through 2028, which resulted in an increase in overall reclamation costs. As a result, as of September 30, 2025, there was an increase in the liabilities related to both the underground mine of $0.2 million and the surface mine of $0.2 million. PNM recorded the increase in the liability related to the underground mine as a regulatory asset and the increase related to the surface mine liability was recognized as a regulatory disallowance on the Condensed Consolidated Statements of Earnings for the three and nine months ended September 30, 2025.

PNM’s estimate of the costs necessary to reclaim the mine that serves SJGS is subject to many assumptions, including the timing of reclamation, generally accepted practices at the time reclamation activities occur, and current inflation and discount rates. PNM cannot predict the ultimate cost to reclaim the mine that serves SJGS and would seek to recover all costs related to reclaiming the underground mine from its customers but could be exposed to additional loss related to surface mine reclamation. In connection with certain mining permits relating to the operation of the San Juan mine, Westmoreland was required to post reclamation bonds of $118.7 million with the NMMMD. In order to facilitate the posting of reclamation bonds by sureties on behalf of Westmoreland, TXNM entered into the WFB LOC Facility under which letters of credit aggregating $19.3 million are outstanding as of September 30, 2026.

The SJGS owners are parties to a reclamation trust funds agreement to provide financial assurance for post-term coal mine reclamation obligations. The trust funds agreement requires each owner to enter into an individual trust agreement with a financial institution as trustee, create an irrevocable reclamation trust, and meet year-end funding targets set by funding curves that are approved by the SJGS ownership. PNM began using its mine reclamation trust to pay for final mine reclamation costs in April 2023. Because the trust agreement requires meeting specific funding targets at year end, it may be necessary for PNM to make additional contributions to meet those targets. PNM contributed $7.0 million in 2025. Based on PNM’s reclamation trust fund balance at September 30, 2026, current forecasts, and current funding curve targets, PNM anticipates contributing $3.4 million in 2026 and anticipates making contributions of $0.4 million in 2027 and $4.7 million in 2028.

PNM recovers from retail customers’ reclamation costs associated with the underground mine. However, the NMPRC capped the amount collected from retail customers for final reclamation of the surface mines at $100.0 million for both SJGS and Four Corners. If future estimates increase the liability for surface mine reclamation, the excess would be expensed at that time. The impacts of changes in New Mexico state law as a result of the enactment of the ETA and regulatory determinations made by the NMPRC may also affect PNM’s financial position, results of operations, and cash flows. PNM is currently unable to determine the outcome of these matters.

In 2021, the San Juan County Commission approved the Coal-Fired Electricity Generating Facility Demolition and Remediation Ordinance (“Ordinance 121”), requiring the full demolition of SJGS upon its complete and permanent closure. Ordinance 121 required the SJGS owners to submit a proposed demolition and remediation plan no later than three months after SJGS was retired. PNM and the other SJGS entered into the San Juan Decommissioning and Trust Funds Agreement, which requires PNM to fund its ownership share of final decommissioning costs into an irrevocable trust. Under the agreement, PNM is required to make funding contributions of which the amount and timing are subject to revised decommissioning cost studies and agreement among the SJGS owners. PNM began using its decommissioning trust to pay for demolition and decommissioning costs in October 2023. PNM has posted a surety bond in the amount of $46.0 million in connection with certain environmental decommissioning obligations and must maintain the bond or other financial assurance until those obligations are satisfied. The surety bond only represents a liability if the SJGS owners fail to deliver on its contractual liability.

On July 29, 2025, PNM received a letter from the NMED indicating that the NMED designated PNM as a responsible party and requiring a Stage 1 Abatement Plan (“S1AP”) proposal for SJGS for groundwater and soil contamination associated with former operations at SJGS. On November 26, 2025, PNM submitted the S1AP to NMED that was approved on February 9, 2026. The S1AP estimates site investigation and monitoring to be completed by the first quarter of 2027. PNM is currently conducting site investigations, groundwater sampling, and monitoring detailed in the S1AP.

Public liability for incidents at nuclear power plants is governed by the Price-Anderson Nuclear Industries Indemnity Act, which limits the liability of nuclear reactor owners to the amount of insurance available from both commercial sources and an industry-wide retrospective payment plan. The insurance limit is subject to an adjustment every five years based upon the aggregate percentage change in the Consumer Price Index. The most recent adjustment took effect on January 1, 2024. As of that date, in accordance with this act, the PVNGS participants are insured against public liability exposure for a nuclear incident up to $16.4 billion per occurrence. PVNGS maintains the maximum available nuclear liability insurance in the amount of $500 million, which is provided by American Nuclear Insurers. The remaining $15.9 billion is provided through a mandatory industry-wide retrospective assessment program. If losses at any nuclear power plant covered by the program exceed the accumulated funds, PNM could be assessed retrospective premium adjustments. The maximum retrospective premium per reactor under the program for each nuclear liability incident is $165.9 million, subject to a maximum annual premium of $24.7 million per incident. Based on PNM’s ownership interest in the three units, PNM’s maximum retrospective premium per incident for all three units is $12.1 million, with a maximum annual payment limitation of $1.8 million, to be adjusted periodically for inflation.