REGULATORY MATTERS	9 Months Ended
Sep. 30, 2026
Regulated Operations [Abstract]
REGULATORY MATTERS	REGULATORY MATTERS FERC REGULATORY MATTERS With respect to their transmission services and rates, the FET Subsidiaries are subject to regulation by FERC. Under the FPA, FERC regulates rates for transmission of electric power, regulatory accounting and reporting under the Uniform System of Accounts, and other matters. FERC regulations require the FET Subsidiaries to provide open access transmission service at FERC-approved rates, terms and conditions. Transmission facilities of the FET Subsidiaries are subject to functional control by PJM, and transmission service using the FET Subsidiaries’ transmission facilities is provided by PJM under the PJM Tariff. Federally enforceable mandatory reliability standards apply to the bulk electric system and impose certain operating, record-keeping and reporting requirements on the FET Subsidiaries. NERC is the ERO designated by FERC to establish and enforce these reliability standards, although NERC has delegated day-to-day implementation and enforcement of these reliability standards to six regional entities, including RFC. All of the facilities that the FET Subsidiaries operate are located within the RFC region. FET actively participates in the NERC and RFC stakeholder processes and otherwise monitors and manages its companies, including the FET Subsidiaries, in response to the ongoing development, implementation and enforcement of the reliability standards implemented and enforced by RFC. FET and the FET Subsidiaries believe that they are in material compliance with all currently-effective and enforceable reliability standards. Nevertheless, in the course of operating its extensive electric utility systems and facilities FET and/or the FET Subsidiaries occasionally learn of isolated facts or circumstances that could be interpreted as excursions from the reliability standards. If and when such occurrences are found, FET and the FET Subsidiaries develop information about the occurrence and develop a remedial response to the specific circumstances, including in appropriate cases “self-reporting” an occurrence to RFC. Moreover, it is clear that NERC, RFC and FERC will continue to refine existing reliability standards as well as to develop and adopt new reliability standards. Any inability on FET's and/or the FET Subsidiaries' part to comply with the reliability standards for its bulk electric system could result in the imposition of financial penalties, or obligations to upgrade or build transmission facilities, that could have a material adverse effect on FET's and/or the FET Subsidiaries' financial condition, results of operations and cash flows. Transmission ROE Incentive On February 24, 2022, the OCC filed a complaint with FERC against ATSI, AEP’s Ohio affiliate and American Electric Power Service Corporation, and Duke Energy Ohio, Inc. asserting that FERC should reduce the ROE utilized in the utilities’ transmission formula rates by eliminating the 50 basis point adder associated with RTO membership, effective February 24, 2022. The OCC contended that this result is required because Ohio law mandates that transmission owning utilities join an RTO and that the 50 basis point adder is applicable only where RTO membership is voluntary. On December 15, 2022, FERC denied the complaint as to ATSI and Duke Energy Ohio, Inc., but granted it as to AEP’s Ohio affiliate. AEP’s Ohio affiliate and OCC appealed FERC’s orders to the Sixth Circuit. On January 17, 2025, the Sixth Circuit ruled that the 50 basis point adder is available only where RTO membership is voluntary, that Ohio law requires Ohio’s transmission utilities to be members of an RTO, and that it was unlawful for FERC to excise the adder from AEP’s Ohio affiliate rates, but not from the Duke Energy Ohio, Inc. and ATSI rates. During 2024, as a result of the ruling, ATSI recognized a $46 million pre-tax charge, with interest, of which $42 million is reported in “Transmission Revenues” and $4 million is reported in “Miscellaneous income, net” on the Consolidated Statements of Income, to reflect the expected refund owed to transmission customers back to February 24, 2022. On June 20, 2025, and June 24, 2025, ATSI and AEP’s Ohio affiliate, respectively, applied for the Supreme Court of the U.S. to review the Sixth Circuit’s decision. On November 10, 2025, the Supreme Court of the U.S. denied ATSI’s petition for the court to review the case. On November 13, 2025, the Sixth Circuit issued a mandate sending the case back to FERC for further proceedings. On June 25, 2026, FERC issued an order on remand directing ATSI to submit a compliance filing within 30 days to remove the RTO incentive and make refunds with interest within 30 days for the period beginning February 24, 2022, through the date of the refund. On July 22, 2026, FERC approved ATSI’s subsequent request to defer the deadline to issue refunds until February 28, 2027, in order to accommodate the PJM and MISO processes for processing refunds as directed by FERC’s order. On July 27, 2026, ATSI submitted to FERC a filing to amend its formula rate to remove on a going-forward basis 50 basis points of authorized earnings in compliance with FERC’s orders. ATSI also filed a request for rehearing on July 27, 2026, arguing that the Federal Power Act limited the refund period to 15 months. On August 27, 2026, FERC denied the request for rehearing by operation of law and on October 30, 2026, FERC issued an order on the merits continuing to deny the request for rehearing. On October 21, 2026, ATSI appealed FERC’s June 25, 2026, order to the Sixth Circuit, where the case remains pending. As of September 30, 2026, ATSI’s estimated refund obligation, including interest, totaled approximately $51 million, which is recorded in “Regulatory liabilities” on FET’s Consolidated Balance Sheets Transmission ROE Methodology A proposed rulemaking proceeding concerning transmission rate incentives provisions of Section 219 of the 2005 Energy Policy Act was initiated in March of 2020 and remains pending before FERC. Among other things, the rulemaking explored whether utilities should collect an “RTO membership” ROE incentive adder for more than three years. FirstEnergy is a member of PJM, and its transmission subsidiaries could be affected by the proposed rulemaking. FirstEnergy participated in comments on the supplemental rulemaking that were submitted by a group of PJM transmission owners and by various industry trade groups. If there were to be any changes to the FET Subsidiaries’ transmission incentive ROE, such changes will be applied on a prospective basis; provided however, due to the Sixth Circuit’s ruling in the Transmission ROE Incentive matter described above, ATSI revised the ROE in its transmission rates effective August 1, 2026. Transmission Planning Supplemental Projects On September 27, 2023, the OCC filed a complaint against ATSI, PJM and other transmission utilities in Ohio alleging that the PJM Tariff and operating agreement are unjust, unreasonable, and unduly discriminatory because they include no provisions to ensure PJM’s review and approval for the planning, need, prudence and cost-effectiveness of the PJM Tariff Attachment M-3 “Supplemental Projects.” Supplemental Projects are projects that are planned and constructed to address local needs on the transmission system. The OCC demands that FERC: (i) require PJM to review supplemental projects for need, prudence and cost-effectiveness; (ii) appoint an independent transmission monitor to assist PJM in such review; and (iii) require that Supplemental Projects go into rate base only through a “stated rate” procedure whereby prior FERC approval would be needed for projects with costs that exceed an established threshold. Subsequently, intervenors expanded the scope of this proceeding to all of the transmission utilities in the PJM market. The FET Subsidiaries and the other transmission utilities in Ohio and in the PJM market filed comments. The matter is pending before FERC. Local Transmission Planning Complaint On December 19, 2024, the Industrial Energy Consumers of America, a group representing large industrial customers, and state consumer advocates filed a complaint at FERC that asserts that transmission owners are overbuilding “local transmission facilities” with corresponding unjustified increases in transmission rates. The complaint demands that FERC: (i) prohibit transmission owners from planning “local transmission facilities” that are rated at 100 kV or higher, (ii) appoint “independent transmission monitors” to conduct such planning, and (iii) condition construction of local transmission facilities on the facility having been planned by the “independent transmission monitor.” FirstEnergy is participating in this matter through a consortium of PJM transmission owners and through certain trade groups, including EEI. FirstEnergy, together with the PJM transmission owners, filed a motion to dismiss the complaint on March 20, 2025, which is pending before FERC. FET is unable to predict the outcome or estimate the impact that this complaint may have on the FET Subsidiaries, however, whether this lawsuit moves forward could have a material impact on FET and its transmission capital investment strategy. Abandonment Transmission Rate Incentive On February 26, 2025, PJM completed its 2024 PJM RTEP Open Window process and, among other actions, designated each of ATSI and PE to construct certain transmission projects. On July 11, 2025, ATSI and PE filed a joint application for the abandonment incentive with FERC, which was approved on September 9, 2025. Effective September 10, 2025, ATSI and PE each became eligible to recover 50% of the project costs incurred prior to September 10, 2025, and 100% of the project costs incurred thereafter for any projects subsequently cancelled for reasons beyond the control of utility management. Large Load Interconnection Rulemaking On October 23, 2025, the U.S. Secretary of Energy directed FERC to conduct a rulemaking procedure to develop regulations that would speed interconnection to the transmission system of large loads, including AI data centers and “hybrid” data center/electric generation facilities. The U.S. Secretary of Energy advanced 14 principles to guide this outcome, including that such large loads should be responsible for paying the costs of any network transmission system upgrades required for interconnection of such large loads. The U.S. Secretary of Energy requested that FERC take final action by April 30, 2026. On October 27, 2025, FERC noticed the U.S. Secretary of Energy’s directive for comment, and subsequently established November 21, 2025, as the deadline for initial comments and December 5, 2025, as the deadline for reply comments. FET and its transmission affiliates, as well as over 150 other parties, filed comments. On June 18, 2026, FERC established a “show cause” proceeding for PJM and the PJM transmission owners, while also establishing similar dockets for each of the other RTOs and ISOs and their respective transmission owners. FERC is using the “show cause” proceeding as a means for the affected transmission owners to submit tariff revisions to address the requirements needed to interconnect and serve customers seeking transmission service on behalf of large loads. On July 28, 2026, PJM filed a motion with FERC advising of its plans to submit the compliance filing in mid-November 2026, which FERC accepted on August 14, 2026. On August 17, 2026, the PJM transmission owners filed a partial compliance filing to set a rate for interim network integration transmission service. On September 22, 2026, FERC issued an order dismissing all requests for rehearing and clarified that the June 18, 2026, order made no final determination and that the matter is in abeyance pending submission of the compliance filing. FET is unable to predict the outcome of this proceeding. Valley Link Formula Transmission Rate On March 14, 2025, the Valley Link joint venture filed an application at FERC for forward-looking formula transmission rates to provide for cost recovery for the portfolio of selected projects. Among other things, the transmission rate application provides for a hypothetical capital structure of 40% debt and 60% equity, and a base ROE of 10.9% with associated templates and protocols, as well as transmission rate incentives, including the abandonment rate incentive, the CWIP rate incentive, the RTO participation adder incentive, the hypothetical capital structure incentive, and the precommercial regulatory asset incentive. On May 14, 2025, FERC issued an initial order that, among other things, accepted the requested abandonment rate incentive, CWIP rate incentive, RTO participation adder incentive, and precommercial regulatory asset rate incentive, and allowed the formula rate to go into effect on May 13, 2025, as requested, subject to refund, pending further settlement and hearing proceedings. Settlement negotiations are ongoing. The hypothetical capital structure incentive and the other open rate design matters are being addressed in confidential settlement negotiations. Grid Growth Formula Transmission Rate On March 6, 2026, the Grid Growth joint venture filed an application at FERC for new forward-looking formula transmission rates to provide for cost recovery for the portfolio of projects that PJM has designated for Grid Growth to construct and operate. Among other things, the transmission rate application provides for a hypothetical capital structure of 40% debt and 60% equity, and a base ROE of 10.8% with associated templates and protocols, as well as transmission rate incentives, including the abandonment rate incentive, the CWIP rate incentive, the hypothetical capital structure incentive, and the precommercial regulatory asset incentive. The application requested an effective date of May 6, 2026. On July 2, 2026, FERC issued an initial order that, among other things, accepted the requested abandonment rate incentive, CWIP rate incentive, the hypothetical capital structure incentive, and precommercial regulatory asset rate incentive, and allowed the formula rate to go into effect on May 6, 2026, as requested, subject to refund, pending further settlement and hearing proceedings. FERC set Grid Growth’s proposed ROE, proxy cost of debt, and formula rate template for settlement and hearing. On August 3, 2026, a group of consumer advocates requested rehearing of FERC’s July 2, 2026, order. On August 12, 2026, the parties commenced confidential settlement negotiations. AMP v. ATSI On February 5, 2026, AMP filed at FERC a complaint against ATSI contesting ATSI’s recovery of certain deferred taxes in ATSI’s 2026 transmission rates. On February 25, 2026, ATSI filed an answer to AMP’s complaint and on May 6, 2026, FERC issued an order affirming ATSI’s position and denying AMP’s challenge. On June 5, 2026, AMP requested a rehearing. FERC did not act on AMP’s rehearing request before the July 2, 2026, statutory deadline. On July 6, 2026, FERC issued a notice of denial stating that it would issue an order on the merits at a later time. On September 24, 2026, FERC issued its order on the merits affirming its May 6, 2026, order. On October 5, 2026, FERC filed an unopposed motion to hold the case in abeyance pending the outcome of AMP’s appeal in a separate FERC proceeding involving AEP; the motion was granted in an order issued on October 20, 2026. PJM Interim Resource Adequacy Service On August 13, 2026, PJM filed with FERC its interim resource adequacy service proposal, which would permit curtailment to data centers that did not bring their own supply of new generation resources. On September 3, 2026, FirstEnergy filed a limited protest of certain elements of PJM’s filing. On October 9, 2026, FERC issued an order accepting PJM’s proposed large load definition and PJM’s proposal to establish a registry to log and track such large loads. FERC rejected all of the remaining elements of PJM’s proposal without prejudice.

Federally enforceable mandatory reliability standards apply to the bulk electric system and impose certain operating, record-keeping and reporting requirements on the FET Subsidiaries. NERC is the ERO designated by FERC to establish and enforce these reliability standards, although NERC has delegated day-to-day implementation and enforcement of these reliability standards to six regional entities, including RFC. All of the facilities that the FET Subsidiaries operate are located within the RFC region. FET actively participates in the NERC and RFC stakeholder processes and otherwise monitors and manages its companies, including the FET Subsidiaries, in response to the ongoing development, implementation and enforcement of the reliability standards implemented and enforced by RFC.

FET and the FET Subsidiaries believe that they are in material compliance with all currently-effective and enforceable reliability standards. Nevertheless, in the course of operating its extensive electric utility systems and facilities FET and/or the FET Subsidiaries occasionally learn of isolated facts or circumstances that could be interpreted as excursions from the reliability standards. If and when such occurrences are found, FET and the FET Subsidiaries develop information about the occurrence and develop a remedial response to the specific circumstances, including in appropriate cases “self-reporting” an occurrence to RFC. Moreover, it is clear that NERC, RFC and FERC will continue to refine existing reliability standards as well as to develop and adopt new reliability standards. Any inability on FET's and/or the FET Subsidiaries' part to comply with the reliability standards for its bulk electric system could result in the imposition of financial penalties, or obligations to upgrade or build transmission facilities, that could have a material adverse effect on FET's and/or the FET Subsidiaries' financial condition, results of operations and cash flows.

On February 24, 2022, the OCC filed a complaint with FERC against ATSI, AEP’s Ohio affiliate and American Electric Power Service Corporation, and Duke Energy Ohio, Inc. asserting that FERC should reduce the ROE utilized in the utilities’ transmission formula rates by eliminating the 50 basis point adder associated with RTO membership, effective February 24, 2022. The OCC contended that this result is required because Ohio law mandates that transmission owning utilities join an RTO and that the 50 basis point adder is applicable only where RTO membership is voluntary. On December 15, 2022, FERC denied the complaint as to ATSI and Duke Energy Ohio, Inc., but granted it as to AEP’s Ohio affiliate. AEP’s Ohio affiliate and OCC appealed FERC’s orders to the Sixth Circuit. On January 17, 2025, the Sixth Circuit ruled that the 50 basis point adder is available only where RTO membership is voluntary, that Ohio law requires Ohio’s transmission utilities to be members of an RTO, and that it was unlawful for FERC to excise the adder from AEP’s Ohio affiliate rates, but not from the Duke Energy Ohio, Inc. and ATSI rates. During 2024, as a result of the ruling, ATSI recognized a $46 million pre-tax charge, with interest, of which $42 million is reported in “Transmission Revenues” and $4 million is reported in “Miscellaneous income, net” on the Consolidated Statements of Income, to reflect the expected refund owed to transmission customers back to February 24, 2022. On June 20, 2025, and June 24, 2025, ATSI and AEP’s Ohio affiliate, respectively, applied for the Supreme Court of the U.S. to review the Sixth Circuit’s decision. On November 10, 2025, the Supreme Court of the U.S. denied ATSI’s petition for the court to review the case. On November 13, 2025, the Sixth Circuit issued a mandate sending the case back to FERC for further proceedings. On June 25, 2026, FERC issued an order on remand directing ATSI to submit a compliance filing within 30 days to remove the RTO incentive and make refunds with interest within 30 days for the period beginning February 24, 2022, through the date of the refund. On July 22, 2026, FERC approved ATSI’s subsequent request to defer the deadline to issue refunds until February 28, 2027, in order to accommodate the PJM and MISO processes for processing refunds as directed by FERC’s order. On July 27, 2026, ATSI submitted to FERC a filing to amend its formula rate to remove on a going-forward basis 50 basis points of authorized earnings in compliance with FERC’s orders. ATSI also filed a request for rehearing on July 27, 2026, arguing that the Federal Power Act limited the refund period to 15 months. On August 27, 2026, FERC denied the request for rehearing by operation of law and on October 30, 2026, FERC issued an order on the merits continuing to deny the request for rehearing. On October 21, 2026, ATSI appealed FERC’s June 25, 2026, order to the Sixth Circuit, where the case remains pending. As of September 30, 2026, ATSI’s estimated refund obligation, including interest, totaled approximately $51 million, which is recorded in “Regulatory liabilities” on FET’s Consolidated Balance Sheets

A proposed rulemaking proceeding concerning transmission rate incentives provisions of Section 219 of the 2005 Energy Policy Act was initiated in March of 2020 and remains pending before FERC. Among other things, the rulemaking explored whether utilities should collect an “RTO membership” ROE incentive adder for more than three years. FirstEnergy is a member of PJM, and its transmission subsidiaries could be affected by the proposed rulemaking. FirstEnergy participated in comments on the supplemental rulemaking that were submitted by a group of PJM transmission owners and by various industry trade groups. If there were to be any changes to the FET Subsidiaries’ transmission incentive ROE, such changes will be applied on a prospective basis; provided however, due to the Sixth Circuit’s ruling in the Transmission ROE Incentive matter described above,

On September 27, 2023, the OCC filed a complaint against ATSI, PJM and other transmission utilities in Ohio alleging that the PJM Tariff and operating agreement are unjust, unreasonable, and unduly discriminatory because they include no provisions to ensure PJM’s review and approval for the planning, need, prudence and cost-effectiveness of the PJM Tariff Attachment M-3 “Supplemental Projects.” Supplemental Projects are projects that are planned and constructed to address local needs on the transmission system. The OCC demands that FERC: (i) require PJM to review supplemental projects for need, prudence and cost-effectiveness; (ii) appoint an independent transmission monitor to assist PJM in such review; and (iii) require that Supplemental Projects go into rate base only through a “stated rate” procedure whereby prior FERC approval would be needed for projects with costs that exceed an established threshold. Subsequently, intervenors expanded the scope of this proceeding to all of the transmission utilities in the PJM market. The FET Subsidiaries and the other transmission utilities in Ohio and in the PJM market filed comments. The matter is pending before FERC.

On December 19, 2024, the Industrial Energy Consumers of America, a group representing large industrial customers, and state consumer advocates filed a complaint at FERC that asserts that transmission owners are overbuilding “local transmission facilities” with corresponding unjustified increases in transmission rates. The complaint demands that FERC: (i) prohibit transmission owners from planning “local transmission facilities” that are rated at 100 kV or higher, (ii) appoint “independent transmission monitors” to conduct such planning, and (iii) condition construction of local transmission facilities on the facility having been planned by the “independent transmission monitor.” FirstEnergy is participating in this matter through a consortium of PJM transmission owners and through certain trade groups, including EEI. FirstEnergy, together with the PJM transmission owners, filed a motion to dismiss the complaint on March 20, 2025, which is pending before FERC. FET is unable to predict the outcome or estimate the impact that this complaint may have on the FET Subsidiaries, however, whether this lawsuit moves forward could have a material impact on FET and its transmission capital investment strategy.

On October 23, 2025, the U.S. Secretary of Energy directed FERC to conduct a rulemaking procedure to develop regulations that would speed interconnection to the transmission system of large loads, including AI data centers and “hybrid” data center/electric generation facilities. The U.S. Secretary of Energy advanced 14 principles to guide this outcome, including that such large loads should be responsible for paying the costs of any network transmission system upgrades required for interconnection of such large loads. The U.S. Secretary of Energy requested that FERC take final action by April 30, 2026. On October 27, 2025, FERC noticed the U.S. Secretary of Energy’s directive for comment, and subsequently established November 21, 2025, as the deadline for initial comments and December 5, 2025, as the deadline for reply comments. FET and its transmission affiliates, as well as over 150 other parties, filed comments. On June 18, 2026, FERC established a “show cause” proceeding for PJM and the PJM transmission owners, while also establishing similar dockets for each of the other RTOs and ISOs and their respective transmission owners. FERC is using the “show cause” proceeding as a means for the affected transmission owners to submit tariff revisions to address the requirements needed to interconnect and serve customers seeking transmission service on behalf of large loads. On July 28, 2026, PJM filed a motion with FERC advising of its plans to submit the compliance filing in mid-November 2026, which FERC accepted on August 14, 2026. On August 17, 2026, the PJM transmission owners filed a partial compliance filing to set a rate for interim network integration transmission service. On September 22, 2026, FERC issued an order dismissing all requests for rehearing and clarified that the June 18, 2026, order made no final determination and that the matter is in abeyance pending submission of the compliance filing. FET is unable to predict the outcome of this proceeding.

On March 14, 2025, the Valley Link joint venture filed an application at FERC for forward-looking formula transmission rates to provide for cost recovery for the portfolio of selected projects. Among other things, the transmission rate application provides for a hypothetical capital structure of 40% debt and 60% equity, and a base ROE of 10.9% with associated templates and protocols, as well as transmission rate incentives, including the abandonment rate incentive, the CWIP rate incentive, the RTO participation adder incentive, the hypothetical capital structure incentive, and the precommercial regulatory asset incentive. On May 14, 2025, FERC issued an initial order that, among other things, accepted the requested abandonment rate incentive, CWIP rate incentive, RTO participation adder incentive, and precommercial regulatory asset rate incentive, and allowed the formula rate to go into effect on May 13, 2025, as requested, subject to refund, pending further settlement and hearing proceedings. Settlement

On March 6, 2026, the Grid Growth joint venture filed an application at FERC for new forward-looking formula transmission rates to provide for cost recovery for the portfolio of projects that PJM has designated for Grid Growth to construct and operate. Among other things, the transmission rate application provides for a hypothetical capital structure of 40% debt and 60% equity, and a base ROE of 10.8% with associated templates and protocols, as well as transmission rate incentives, including the abandonment rate incentive, the CWIP rate incentive, the hypothetical capital structure incentive, and the precommercial regulatory asset incentive. The application requested an effective date of May 6, 2026. On July 2, 2026, FERC issued an initial order that, among other things, accepted the requested abandonment rate incentive, CWIP rate incentive, the hypothetical capital structure incentive, and precommercial regulatory asset rate incentive, and allowed the formula rate to go into effect on May 6, 2026, as requested, subject to refund, pending further settlement and hearing proceedings. FERC set Grid Growth’s proposed ROE, proxy cost of debt, and formula rate template for settlement and hearing. On August 3, 2026, a group of consumer advocates requested rehearing of FERC’s July 2, 2026, order. On August 12, 2026, the parties commenced confidential settlement negotiations.

On February 5, 2026, AMP filed at FERC a complaint against ATSI contesting ATSI’s recovery of certain deferred taxes in ATSI’s 2026 transmission rates. On February 25, 2026, ATSI filed an answer to AMP’s complaint and on May 6, 2026, FERC issued an order affirming ATSI’s position and denying AMP’s challenge. On June 5, 2026, AMP requested a rehearing. FERC did not act on AMP’s rehearing request before the July 2, 2026, statutory deadline. On July 6, 2026, FERC issued a notice of denial stating that it would issue an order on the merits at a later time. On September 24, 2026, FERC issued its order on the merits affirming its May 6, 2026, order. On October 5, 2026, FERC filed an unopposed motion to hold the case in abeyance pending the outcome of AMP’s appeal in a separate FERC proceeding involving AEP; the motion was granted in an order issued on October 20, 2026.