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Benefit Plans | 12 Months Ended
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Dec. 31, 2023
Benefit Plans | BENEFIT PLANS The disclosures in this note apply to all Registrants except AEPTCo unless indicated otherwise. For a discussion of investment strategy, investment limitations, target asset allocations and the classification of investments within the fair value hierarchy, see “Fair Value Measurements of Assets and Liabilities” and “Investments Held in Trust for Future Liabilities” sections of Note 1. AEPSC sponsors a qualified pension plan and two unfunded non-qualified pension plans. Substantially all AEP subsidiary employees are covered by the qualified plan or both the qualified and a non-qualified pension plan. AEPSC also sponsors OPEB plans to provide health and life insurance benefits for retired employees. Due to the Registrant Subsidiaries’ participation in AEP’s benefit plans, the assumptions used by the actuary, with the exception of the rate of compensation increase, and the accounting for the plans by each subsidiary are the same. This section details the assumptions that apply to all Registrants and the rate of compensation increase for each Registrant. The Registrants recognize the funded status associated with defined benefit pension and OPEB plans on the balance sheets. Disclosures about the plans are required by the “Compensation – Retirement Benefits” accounting guidance. The Registrants recognize an asset for a plan’s overfunded status or a liability for a plan’s underfunded status, and recognize, as a component of other comprehensive income, the changes in the funded status of the plan that arise during the year that are not recognized as a component of net periodic benefit cost. The Registrants record a regulatory asset instead of other comprehensive income for qualifying benefit costs of regulated operations that for rate-making purposes are deferred for future recovery. The cumulative funded status adjustment is equal to the remaining unrecognized deferrals for unamortized actuarial losses or gains, prior service costs and transition obligations, such that remaining deferred costs result in an AOCI equity reduction or regulatory asset and deferred gains result in an AOCI equity addition or regulatory liability. Actuarial Assumptions for Benefit Obligations The weighted-average assumptions used in the measurement of the Registrants’ benefit obligations are shown in the following tables:
|  | Pension Plans |  | OPEB
|  | December 31,
Assumption |  | 2023 |  | 2022 |  | 2023 |  | 2022
Discount Rate |  | 5.15 | % |  | 5.50 | % |  | 5.15 | % |  | 5.50 | %
Interest Crediting Rate |  | 4.00 | % |  | 4.25 | % |  | NA |  | NA
NA Not applicable.
Assumption – Rate of Compensation Increase (a) - Pension Plans
|  | AEP |  | AEP Texas |  | APCo |  | I&M |  | OPCo |  | PSO |  | SWEPCo
December 31, 2023 |  | 5.05 | % |  | 5.20 | % |  | 4.95 | % |  | 5.05 | % |  | 5.45 | % |  | 5.20 | % |  | 5.00 | %
December 31, 2022 |  | 5.05 | % |  | 5.15 | % |  | 4.90 | % |  | 5.00 | % |  | 5.35 | % |  | 5.15 | % |  | 5.00 | %
(a)Rates are for base pay only. In addition, an amount is added to reflect target incentive compensation for exempt employees and overtime and incentive pay for nonexempt employees. A duration-based method is used to determine the discount rate for the plans. A hypothetical portfolio of high quality corporate bonds is constructed with cash flows matching the benefit plan liability. The composite yield on the hypothetical bond portfolio is used as the discount rate for the plan. The discount rate is the same for each Registrant. For 2023, the rate of compensation increase assumed varies with the age of the employee, ranging from 3% per year to 11.5% per year, with the average increase shown in the table above. The compensation increase rates reflect variations in each Registrants’ population participating in the pension plan. Actuarial Assumptions for Net Periodic Benefit Costs The weighted-average assumptions used in the measurement of each Registrants’ benefit costs are shown in the following tables:
|  | Pension Plans |  | OPEB
|  | Year Ended December 31,
Assumption |  | 2023 |  | 2022 |  | 2021 |  | 2023 |  | 2022 |  | 2021
Discount Rate |  | 5.50 | % |  | 2.90 | % |  | 2.50 | % |  | 5.50 | % |  | 2.90 | % |  | 2.55 | %
Interest Crediting Rate |  | 4.25 | % |  | 4.00 | % |  | 4.00 | % |  | NA |  | NA |  | NA
Expected Return on Plan Assets |  | 7.50 | % |  | 5.25 | % |  | 4.75 | % |  | 7.25 | % |  | 5.50 | % |  | 4.75 | %
NA Not applicable.
Assumption – Rate of Compensation Increase (a) - Pension Plans
|  | AEP |  | AEP Texas |  | APCo |  | I&M |  | OPCo |  | PSO |  | SWEPCo
December 31, 2023 |  | 5.05 | % |  | 5.20 | % |  | 4.95 | % |  | 5.05 | % |  | 5.45 | % |  | 5.20 | % |  | 5.00 | %
December 31, 2022 |  | 5.05 | % |  | 5.15 | % |  | 4.90 | % |  | 5.00 | % |  | 5.35 | % |  | 5.15 | % |  | 5.00 | %
December 31, 2021 |  | 5.10 | % |  | 5.10 | % |  | 4.85 | % |  | 5.00 | % |  | 5.30 | % |  | 5.10 | % |  | 4.95 | %
(a)Rates are for base pay only. In addition, an amount is added to reflect target incentive compensation for exempt employees and overtime and incentive pay for nonexempt employees. The expected return on plan assets was determined by evaluating historical returns, the current investment climate (yield on fixed income securities and other recent investment market indicators), rate of inflation, third-party forecasts and current prospects for economic growth. The expected return on plan assets is the same for each Registrant. The health care trend rate assumptions used for OPEB plans measurement purposes are shown below:
Health Care Trend Rates |  | December 31, 2023 |  | December 31, 2022
Initial |  | 7.00 | % |  | 7.50 | %
Ultimate |  | 4.50 | % |  | 4.50 | %
Year Ultimate Reached |  | 2030 |  | 2029
Significant Concentrations of Risk within Plan Assets In addition to establishing the target asset allocation of plan assets, the investment policy also places restrictions on securities to limit significant concentrations within plan assets. The investment policy establishes guidelines that govern maximum market exposure, security restrictions, prohibited asset classes, prohibited types of transactions, minimum credit quality, average portfolio credit quality, portfolio duration and concentration limits. The guidelines were established to mitigate the risk of loss due to significant concentrations in any investment. Management monitors the plans to control security diversification and ensure compliance with the investment policy. As of December 31, 2023, the assets were invested in compliance with all investment limits. See “Investments Held in Trust for Future Liabilities” section of Note 1 for limit details. Benefit Plan Obligations, Plan Assets, Funded Status and Amounts Recognized on the Balance Sheets For the year ended December 31, 2023, the pension plans had an actuarial loss primarily due to a decrease in the discount rate, and to a lesser extent the effect of demographic experience (updated census data on January 1, 2023). These losses were partially offset by decreasing the cash balance account interest crediting rate. For the year ended December 31, 2023, the OPEB plans had an actuarial loss primarily due to discount rates, as well as actual net benefit payments above expected. These losses were partially offset by updated per capita cost assumptions. For the year ended December 31, 2022, the pension plans had an actuarial gain primarily due to an increase in the discount rate and was partially offset by increases in the assumed lump sum conversion rate and cash balance account interest crediting rate. For the year ended December 31, 2022, the OPEB plans had an actuarial gain primarily due to an increase in the discount rate and updated per capita cost assumptions. The OPEB plans gains were partially offset by a projected reduction in the Employer Group Waiver Program catastrophic reinsurance offset provided to AEP, resulting from the Inflation Reduction Act as well as an increase in the health care cost trend assumption. The following tables provide a reconciliation of the changes in the plans’ benefit obligations, fair value of plan assets, funded status and the presentation on the balance sheets. The benefit obligation for the defined benefit pension and OPEB plans are the projected benefit obligation and the accumulated benefit obligation, respectively. Pension Plans
2023 |  | AEP |  | AEP Texas |  | APCo |  | I&M |  | OPCo |  | PSO |  | SWEPCo
Change in Benefit Obligation |  | (in millions)
Benefit Obligation as of January 1, |  | $ | 4,072.7 |  |  | $ | 334.1 |  |  | $ | 485.7 |  |  | $ | 466.8 |  |  | $ | 363.6 |  |  | $ | 192.3 |  |  | $ | 250.7 |
Service Cost |  | 94.3 |  |  | 8.2 |  |  | 9.1 |  |  | 11.9 |  |  | 8.4 |  |  | 5.5 |  |  | 7.7 |
Interest Cost |  | 219.2 |  |  | 18.3 |  |  | 26.4 |  |  | 24.9 |  |  | 19.8 |  |  | 10.7 |  |  | 13.9 |
Actuarial Loss |  | 144.0 |  |  | 20.1 |  |  | 23.2 |  |  | 8.5 |  |  | 17.5 |  |  | 13.6 |  |  | 16.8 |
Benefit Payments |  | (368.6) |  |  | (37.6) |  |  | (40.3) |  |  | (35.1) |  |  | (30.9) |  |  | (19.9) |  |  | (27.9) |
Benefit Obligation as of December 31, |  | $ | 4,161.6 |  |  | $ | 343.1 |  |  | $ | 504.1 |  |  | $ | 477.0 |  |  | $ | 378.4 |  |  | $ | 202.2 |  |  | $ | 261.2 |
Change in Fair Value of Plan Assets |  |  |  |  |  |  |  |  |  |  |  |  |  |
Fair Value of Plan Assets as of January 1, |  | $ | 4,124.7 |  |  | $ | 335.1 |  |  | $ | 531.7 |  |  | $ | 533.7 |  |  | $ | 406.4 |  |  | $ | 218.5 |  |  | $ | 231.3 |
Actual Gain on Plan Assets |  | 353.8 |  |  | 34.8 |  |  | 58.4 |  |  | 51.5 |  |  | 44.0 |  |  | 24.0 |  |  | 23.9 |
Company Contributions (a) |  | 8.3 |  |  | 0.4 |  |  | — |  |  | 0.5 |  |  | — |  |  | 0.1 |  |  | 0.2 |
Benefit Payments |  | (368.6) |  |  | (37.6) |  |  | (40.3) |  |  | (35.1) |  |  | (30.9) |  |  | (19.9) |  |  | (27.9) |
Fair Value of Plan Assets as of December 31, |  | $ | 4,118.2 |  |  | $ | 332.7 |  |  | $ | 549.8 |  |  | $ | 550.6 |  |  | $ | 419.5 |  |  | $ | 222.7 |  |  | $ | 227.5 |
Funded (Underfunded) Status as of December 31, |  | $ | (43.4) |  |  | $ | (10.4) |  |  | $ | 45.7 |  |  | $ | 73.6 |  |  | $ | 41.1 |  |  | $ | 20.5 |  |  | $ | (33.7) |
2022 |  | AEP |  | AEP Texas |  | APCo |  | I&M |  | OPCo |  | PSO |  | SWEPCo
Change in Benefit Obligation |  | (in millions)
Benefit Obligation as of January 1, |  | $ | 5,187.0 |  |  | $ | 419.8 |  |  | $ | 621.7 |  |  | $ | 612.1 |  |  | $ | 470.7 |  |  | $ | 252.6 |  |  | $ | 317.7 |
Service Cost |  | 123.1 |  |  | 11.1 |  |  | 11.4 |  |  | 16.2 |  |  | 11.2 |  |  | 7.4 |  |  | 10.6 |
Interest Cost |  | 148.2 |  |  | 12.1 |  |  | 17.5 |  |  | 17.0 |  |  | 13.3 |  |  | 7.0 |  |  | 9.1 |
Actuarial Gain |  | (983.4) |  |  | (67.8) |  |  | (123.1) |  |  | (138.0) |  |  | (97.9) |  |  | (52.9) |  |  | (57.9) |
Benefit Payments |  | (402.2) |  |  | (41.1) |  |  | (41.8) |  |  | (40.5) |  |  | (33.7) |  |  | (21.8) |  |  | (28.8) |
Benefit Obligation as of December 31, |  | $ | 4,072.7 |  |  | $ | 334.1 |  |  | $ | 485.7 |  |  | $ | 466.8 |  |  | $ | 363.6 |  |  | $ | 192.3 |  |  | $ | 250.7 |
Change in Fair Value of Plan Assets |  |  |  |  |  |  |  |  |  |  |  |  |  |
Fair Value of Plan Assets as of January 1, |  | $ | 5,352.9 |  |  | $ | 444.9 |  |  | $ | 683.3 |  |  | $ | 681.5 |  |  | $ | 524.8 |  |  | $ | 286.2 |  |  | $ | 308.3 |
Actual (Loss) on Plan Assets |  | (833.7) |  |  | (69.2) |  |  | (109.8) |  |  | (107.4) |  |  | (84.8) |  |  | (46.0) |  |  | (48.3) |
Company Contributions (a) |  | 7.7 |  |  | 0.5 |  |  | — |  |  | 0.1 |  |  | 0.1 |  |  | 0.1 |  |  | 0.1 |
Benefit Payments |  | (402.2) |  |  | (41.1) |  |  | (41.8) |  |  | (40.5) |  |  | (33.7) |  |  | (21.8) |  |  | (28.8) |
Fair Value of Plan Assets as of December 31, |  | $ | 4,124.7 |  |  | $ | 335.1 |  |  | $ | 531.7 |  |  | $ | 533.7 |  |  | $ | 406.4 |  |  | $ | 218.5 |  |  | $ | 231.3 |
Funded (Underfunded) Status as of December 31, |  | $ | 52.0 |  |  | $ | 1.0 |  |  | $ | 46.0 |  |  | $ | 66.9 |  |  | $ | 42.8 |  |  | $ | 26.2 |  |  | $ | (19.4) |
(a)No contributions were made to the qualified pension plan for the years ended December 31, 2023 and 2022, respectively. Contributions to the non-qualified pension plans were $8 million and $8 million for the years ended December 31, 2023 and 2022, respectively. OPEB
2023 |  | AEP |  | AEP Texas |  | APCo |  | I&M |  | OPCo |  | PSO |  | SWEPCo
Change in Benefit Obligation |  | (in millions)
Benefit Obligation as of January 1, |  | $ | 872.6 |  |  | $ | 68.6 |  |  | $ | 140.7 |  |  | $ | 101.9 |  |  | $ | 88.9 |  |  | $ | 45.7 |  |  | $ | 55.1 |
Service Cost |  | 4.6 |  |  | 0.3 |  |  | 0.5 |  |  | 0.6 |  |  | 0.4 |  |  | 0.3 |  |  | 0.4 |
Interest Cost |  | 46.2 |  |  | 3.6 |  |  | 7.4 |  |  | 5.4 |  |  | 4.7 |  |  | 2.4 |  |  | 2.9 |
Actuarial Loss |  | 19.8 |  |  | 1.2 |  |  | 0.9 |  |  | 3.2 |  |  | 2.2 |  |  | 0.4 |  |  | 1.2 |
Benefit Payments |  | (137.8) |  |  | (10.7) |  |  | (21.6) |  |  | (18.3) |  |  | (15.0) |  |  | (7.6) |  |  | (8.8) |
Participant Contributions |  | 43.6 |  |  | 3.4 |  |  | 6.6 |  |  | 6.0 |  |  | 4.7 |  |  | 2.5 |  |  | 2.9 |
Medicare Subsidy |  | 0.5 |  |  | — |  |  | 0.1 |  |  | — |  |  | — |  |  | — |  |  | — |
Benefit Obligation as of December 31, |  | $ | 849.5 |  |  | $ | 66.4 |  |  | $ | 134.6 |  |  | $ | 98.8 |  |  | $ | 85.9 |  |  | $ | 43.7 |  |  | $ | 53.7 |
Change in Fair Value of Plan Assets |  |  |  |  |  |  |  |  |  |  |  |  |  |
Fair Value of Plan Assets as of January 1, |  | $ | 1,549.3 |  |  | $ | 128.3 |  |  | $ | 228.6 |  |  | $ | 190.5 |  |  | $ | 166.2 |  |  | $ | 85.4 |  |  | $ | 103.0 |
Actual Gain on Plan Assets |  | 213.2 |  |  | 16.5 |  |  | 28.1 |  |  | 26.4 |  |  | 21.9 |  |  | 9.9 |  |  | 14.0 |
Company Contributions |  | 5.0 |  |  | — |  |  | 1.3 |  |  | — |  |  | — |  |  | — |  |  | — |
Participant Contributions |  | 43.6 |  |  | 3.4 |  |  | 6.6 |  |  | 6.0 |  |  | 4.7 |  |  | 2.5 |  |  | 2.9 |
Benefit Payments |  | (137.8) |  |  | (10.7) |  |  | (21.6) |  |  | (18.3) |  |  | (15.0) |  |  | (7.6) |  |  | (8.8) |
Fair Value of Plan Assets as of December 31, |  | $ | 1,673.3 |  |  | $ | 137.5 |  |  | $ | 243.0 |  |  | $ | 204.6 |  |  | $ | 177.8 |  |  | $ | 90.2 |  |  | $ | 111.1 |
Funded Status as of December 31, |  | $ | 823.8 |  |  | $ | 71.1 |  |  | $ | 108.4 |  |  | $ | 105.8 |  |  | $ | 91.9 |  |  | $ | 46.5 |  |  | $ | 57.4 |
2022 |  | AEP |  | AEP Texas |  | APCo |  | I&M |  | OPCo |  | PSO |  | SWEPCo
Change in Benefit Obligation |  | (in millions)
Benefit Obligation as of January 1, |  | $ | 1,041.3 |  |  | $ | 80.5 |  |  | $ | 167.3 |  |  | $ | 118.6 |  |  | $ | 104.9 |  |  | $ | 54.4 |  |  | $ | 65.2 |
Service Cost |  | 7.4 |  |  | 0.5 |  |  | 0.8 |  |  | 0.9 |  |  | 0.6 |  |  | 0.4 |  |  | 0.6 |
Interest Cost |  | 29.2 |  |  | 2.2 |  |  | 4.7 |  |  | 3.4 |  |  | 3.0 |  |  | 1.5 |  |  | 1.8 |
Actuarial Gain |  | (109.8) |  |  | (7.1) |  |  | (16.2) |  |  | (8.7) |  |  | (8.9) |  |  | (5.2) |  |  | (6.6) |
Benefit Payments |  | (140.1) |  |  | (10.9) |  |  | (23.0) |  |  | (18.3) |  |  | (15.5) |  |  | (7.9) |  |  | (8.8) |
Participant Contributions |  | 44.1 |  |  | 3.4 |  |  | 7.0 |  |  | 6.0 |  |  | 4.8 |  |  | 2.5 |  |  | 2.9 |
Medicare Subsidy |  | 0.5 |  |  | — |  |  | 0.1 |  |  | — |  |  | — |  |  | — |  |  | — |
Benefit Obligation as of December 31, |  | $ | 872.6 |  |  | $ | 68.6 |  |  | $ | 140.7 |  |  | $ | 101.9 |  |  | $ | 88.9 |  |  | $ | 45.7 |  |  | $ | 55.1 |
Change in Fair Value of Plan Assets |  |  |  |  |  |  |  |  |  |  |  |  |  |
Fair Value of Plan Assets as of January 1, |  | $ | 2,044.3 |  |  | $ | 168.8 |  |  | $ | 302.3 |  |  | $ | 248.7 |  |  | $ | 220.0 |  |  | $ | 114.0 |  |  | $ | 136.6 |
Actual Loss on Plan Assets |  | (403.6) |  |  | (33.0) |  |  | (59.3) |  |  | (45.9) |  |  | (43.1) |  |  | (23.2) |  |  | (27.7) |
Company Contributions |  | 4.6 |  |  | — |  |  | 1.6 |  |  | — |  |  | — |  |  | — |  |  | — |
Participant Contributions |  | 44.1 |  |  | 3.4 |  |  | 7.0 |  |  | 6.0 |  |  | 4.8 |  |  | 2.5 |  |  | 2.9 |
Benefit Payments |  | (140.1) |  |  | (10.9) |  |  | (23.0) |  |  | (18.3) |  |  | (15.5) |  |  | (7.9) |  |  | (8.8) |
Fair Value of Plan Assets as of December 31, |  | $ | 1,549.3 |  |  | $ | 128.3 |  |  | $ | 228.6 |  |  | $ | 190.5 |  |  | $ | 166.2 |  |  | $ | 85.4 |  |  | $ | 103.0 |
Funded Status as of December 31, |  | $ | 676.7 |  |  | $ | 59.7 |  |  | $ | 87.9 |  |  | $ | 88.6 |  |  | $ | 77.3 |  |  | $ | 39.7 |  |  | $ | 47.9 |
Amounts Included on the Balance Sheets Related to Funded Status Pension Plans
December 31, 2023 |  | AEP |  | AEP Texas |  | APCo |  | I&M |  | OPCo |  | PSO |  | SWEPCo
|  | (in millions)
Other Noncurrent Assets - Employee Benefits and Pension Assets |  | $ | 17.3 |  |  | $ | 0.1 |  |  | $ | 46.0 |  |  | $ | 74.8 |  |  | $ | 41.4 |  |  | $ | 21.8 |  |  | $ | — |
Other Current Liabilities – Accrued Short-term Benefit Liability |  | (6.7) |  |  | (0.3) |  |  | — |  |  | — |  |  | — |  |  | (0.1) |  |  | (0.1) |
Other Noncurrent Liabilities – Accrued Long-term Benefit Liability |  | (54.0) |  |  | (10.2) |  |  | (0.3) |  |  | (1.2) |  |  | (0.3) |  |  | (1.2) |  |  | (33.6) |
Funded (Underfunded) Status |  | $ | (43.4) |  |  | $ | (10.4) |  |  | $ | 45.7 |  |  | $ | 73.6 |  |  | $ | 41.1 |  |  | $ | 20.5 |  |  | $ | (33.7) |
December 31, 2022 |  | AEP |  | AEP Texas |  | APCo |  | I&M |  | OPCo |  | PSO |  | SWEPCo
|  | (in millions)
Other Noncurrent Assets - Employee Benefits and Pension Assets |  | $ | 113.4 |  |  | $ | 3.7 |  |  | $ | 46.6 |  |  | $ | 68.5 |  |  | $ | 43.1 |  |  | $ | 27.6 |  |  | $ | — |
Other Current Liabilities – Accrued Short-term Benefit Liability |  | (6.3) |  |  | (0.4) |  |  | — |  |  | (0.1) |  |  | — |  |  | (0.1) |  |  | (0.1) |
Other Noncurrent Liabilities – Accrued Long-term Benefit Liability |  | (55.1) |  |  | (2.3) |  |  | (0.6) |  |  | (1.5) |  |  | (0.3) |  |  | (1.3) |  |  | (19.3) |
Funded (Underfunded) Status |  | $ | 52.0 |  |  | $ | 1.0 |  |  | $ | 46.0 |  |  | $ | 66.9 |  |  | $ | 42.8 |  |  | $ | 26.2 |  |  | $ | (19.4) |
OPEB
December 31, 2023 |  | AEP |  | AEP Texas |  | APCo |  | I&M |  | OPCo |  | PSO |  | SWEPCo
|  | (in millions)
Other Noncurrent Assets - Employee Benefits and Pension Assets |  | $ | 838.0 |  |  | $ | 71.1 |  |  | $ | 125.6 |  |  | $ | 105.8 |  |  | $ | 91.9 |  |  | $ | 46.5 |  |  | $ | 57.4 |
Other Current Liabilities – Accrued Short-term Benefit Liability |  | (2.4) |  |  | — |  |  | (1.6) |  |  | — |  |  | — |  |  | — |  |  | — |
Other Noncurrent Liabilities – Accrued Long-term Benefit Liability |  | (11.8) |  |  | — |  |  | (15.6) |  |  | — |  |  | — |  |  | — |  |  | — |
Funded Status |  | $ | 823.8 |  |  | $ | 71.1 |  |  | $ | 108.4 |  |  | $ | 105.8 |  |  | $ | 91.9 |  |  | $ | 46.5 |  |  | $ | 57.4 |
December 31, 2022 |  | AEP |  | AEP Texas |  | APCo |  | I&M |  | OPCo |  | PSO |  | SWEPCo
|  | (in millions)
Other Noncurrent Assets - Employee Benefits and Pension Assets |  | $ | 699.5 |  |  | $ | 59.7 |  |  | $ | 106.3 |  |  | $ | 88.6 |  |  | $ | 77.3 |  |  | $ | 39.7 |  |  | $ | 47.9 |
Other Current Liabilities – Accrued Short-term Benefit Liability |  | (2.5) |  |  | — |  |  | (1.6) |  |  | — |  |  | — |  |  | — |  |  | — |
Other Noncurrent Liabilities – Accrued Long-term Benefit Liability |  | (20.3) |  |  | — |  |  | (16.8) |  |  | — |  |  | — |  |  | — |  |  | — |
Funded Status |  | $ | 676.7 |  |  | $ | 59.7 |  |  | $ | 87.9 |  |  | $ | 88.6 |  |  | $ | 77.3 |  |  | $ | 39.7 |  |  | $ | 47.9 |
Amounts Included in Regulatory Assets, Deferred Income Taxes and AOCI The following tables show the components of the plans included in Regulatory Assets, Deferred Income Taxes and AOCI and the items attributable to the change in these components: Pension Plans
December 31, 2023 |  | AEP |  | AEP Texas |  | APCo |  | I&M |  | OPCo |  | PSO |  | SWEPCo
Components |  | (in millions)
Net Actuarial (Gain) Loss |  | $ | 1,063.4 |  |  | $ | 175.2 |  |  | $ | 104.9 |  |  | $ | (5.8) |  |  | $ | 131.9 |  |  | $ | 46.7 |  |  | $ | 89.6 |
Prior Service Cost |  | 0.2 |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |
Recorded as |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory Assets |  | $ | 938.6 |  |  | $ | 163.4 |  |  | $ | 102.6 |  |  | $ | 6.4 |  |  | $ | 131.9 |  |  | $ | 46.7 |  |  | $ | 89.7 |
Deferred Income Taxes |  | 26.4 |  |  | 2.7 |  |  | 0.4 |  |  | (2.6) |  |  | — |  |  | — |  |  | — |
Net of Tax AOCI |  | 98.6 |  |  | 9.1 |  |  | 1.9 |  |  | (9.6) |  |  | — |  |  | — |  |  | (0.1) |
December 31, 2023 |  | AEP |  | AEP Texas |  | APCo |  | I&M |  | OPCo |  | PSO |  | SWEPCo
Components |  | (in millions)
Actuarial Loss During the Year |  | $ | 129.2 |  |  | $ | 13.4 |  |  | $ | 9.3 |  |  | $ | 1.2 |  |  | $ | 7.6 |  |  | $ | 7.9 |  |  | $ | 12.1 |
Amortization of Actuarial Loss |  | (1.4) |  |  | (0.1) |  |  | — |  |  | (0.1) |  |  | — |  |  | — |  |  | (0.1) |
Change for the Year Ended December 31, |  | $ | 127.8 |  |  | $ | 13.3 |  |  | $ | 9.3 |  |  | $ | 1.1 |  |  | $ | 7.6 |  |  | $ | 7.9 |  |  | $ | 12.0 |
December 31, 2022 |  | AEP |  | AEP Texas |  | APCo |  | I&M |  | OPCo |  | PSO |  | SWEPCo
Components |  | (in millions)
Net Actuarial (Gain) Loss |  | $ | 935.6 |  |  | $ | 161.9 |  |  | $ | 95.6 |  |  | $ | (6.9) |  |  | $ | 124.3 |  |  | $ | 38.8 |  |  | $ | 77.6 |
Prior Service Cost |  | 0.2 |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |
Recorded as |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory Assets |  | $ | 841.8 |  |  | $ | 151.2 |  |  | $ | 93.6 |  |  | $ | 4.8 |  |  | $ | 124.3 |  |  | $ | 38.8 |  |  | $ | 77.6 |
Deferred Income Taxes |  | 19.9 |  |  | 2.4 |  |  | 0.4 |  |  | (2.4) |  |  | — |  |  | — |  |  | — |
Net of Tax AOCI |  | 74.1 |  |  | 8.3 |  |  | 1.6 |  |  | (9.3) |  |  | — |  |  | — |  |  | — |
December 31, 2022 |  | AEP |  | AEP Texas |  | APCo |  | I&M |  | OPCo |  | PSO |  | SWEPCo
Components |  | (in millions)
Actuarial Loss During the Year |  | $ | 103.9 |  |  | $ | 22.4 |  |  | $ | 19.1 |  |  | $ | 1.8 |  |  | $ | 11.7 |  |  | $ | 6.7 |  |  | $ | 5.0 |
Amortization of Actuarial Loss |  | (63.0) |  |  | (5.2) |  |  | (7.4) |  |  | (7.1) |  |  | (5.5) |  |  | (2.9) |  |  | (3.8) |
Change for the Year Ended December 31, |  | $ | 40.9 |  |  | $ | 17.2 |  |  | $ | 11.7 |  |  | $ | (5.3) |  |  | $ | 6.2 |  |  | $ | 3.8 |  |  | $ | 1.2 |
OPEB
December 31, 2023 |  | AEP |  | AEP Texas |  | APCo |  | I&M |  | OPCo |  | PSO |  | SWEPCo
Components |  | (in millions)
Net Actuarial Loss |  | $ | 201.5 |  |  | $ | 22.1 |  |  | $ | 27.1 |  |  | $ | 28.7 |  |  | $ | 18.1 |  |  | $ | 17.5 |  |  | $ | 18.4 |
Prior Service Credit |  | (27.4) |  |  | (2.3) |  |  | (4.2) |  |  | (3.7) |  |  | (2.9) |  |  | (1.6) |  |  | (2.1) |
Recorded as |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory Assets |  | $ | 106.1 |  |  | $ | 19.8 |  |  | $ | 13.2 |  |  | $ | 19.0 |  |  | $ | 15.2 |  |  | $ | 15.9 |  |  | $ | 10.2 |
Deferred Income Taxes |  | 14.3 |  |  | — |  |  | 2.0 |  |  | 1.3 |  |  | — |  |  | — |  |  | 1.3 |
Net of Tax AOCI |  | 53.7 |  |  | — |  |  | 7.7 |  |  | 4.7 |  |  | — |  |  | — |  |  | 4.8 |
December 31, 2023 |  | AEP |  | AEP Texas |  | APCo |  | I&M |  | OPCo |  | PSO |  | SWEPCo
Components |  | (in millions)
Actuarial Gain During the Year |  | $ | (83.7) |  |  | $ | (6.4) |  |  | $ | (11.1) |  |  | $ | (9.6) |  |  | $ | (7.9) |  |  | $ | (3.7) |  |  | $ | (5.6) |
Amortization of Actuarial Loss |  | (14.8) |  |  | (1.2) |  |  | (2.3) |  |  | (1.9) |  |  | (1.6) |  |  | (0.8) |  |  | (1.0) |
Amortization of Prior Service Credit |  | 63.1 |  |  | 5.3 |  |  | 9.2 |  |  | 8.7 |  |  | 6.3 |  |  | 4.0 |  |  | 4.9 |
Change for the Year Ended December 31, |  | $ | (35.4) |  |  | $ | (2.3) |  |  | $ | (4.2) |  |  | $ | (2.8) |  |  | $ | (3.2) |  |  | $ | (0.5) |  |  | $ | (1.7) |
December 31, 2022 |  | AEP |  | AEP Texas |  | APCo |  | I&M |  | OPCo |  | PSO |  | SWEPCo
Components |  | (in millions)
Net Actuarial Loss |  | $ | 300.0 |  |  | $ | 29.7 |  |  | $ | 40.5 |  |  | $ | 40.2 |  |  | $ | 27.6 |  |  | $ | 22.0 |  |  | $ | 25.0 |
Prior Service Credit |  | (90.5) |  |  | (7.6) |  |  | (13.4) |  |  | (12.4) |  |  | (9.2) |  |  | (5.6) |  |  | (7.0) |
Recorded as |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory Assets |  | $ | 126.0 |  |  | $ | 22.0 |  |  | $ | 14.7 |  |  | $ | 22.1 |  |  | $ | 18.4 |  |  | $ | 16.4 |  |  | $ | 11.2 |
Deferred Income Taxes |  | 17.5 |  |  | 0.1 |  |  | 2.5 |  |  | 1.2 |  |  | — |  |  | — |  |  | 1.5 |
Net of Tax AOCI |  | 66.0 |  |  | — |  |  | 9.9 |  |  | 4.5 |  |  | — |  |  | — |  |  | 5.3 |
December 31, 2022 |  | AEP |  | AEP Texas |  | APCo |  | I&M |  | OPCo |  | PSO |  | SWEPCo
Components |  | (in millions)
Actuarial Loss During the Year |  | $ | 403.6 |  |  | $ | 34.9 |  |  | $ | 59.4 |  |  | $ | 50.9 |  |  | $ | 46.1 |  |  | $ | 24.1 |  |  | $ | 28.5 |
Amortization of Prior Service Credit |  | 71.4 |  |  | 6.1 |  |  | 10.4 |  |  | 9.7 |  |  | 7.1 |  |  | 4.4 |  |  | 5.3 |
Change for the Year Ended December 31, |  | $ | 475.0 |  |  | $ | 41.0 |  |  | $ | 69.8 |  |  | $ | 60.6 |  |  | $ | 53.2 |  |  | $ | 28.5 |  |  | $ | 33.8 |
Determination of Pension Expense The determination of pension expense or income is based on a market-related valuation of assets which reduces year-to-year volatility. This market-related valuation recognizes investment gains or losses over a five-year period from the year in which they occur. Investment gains or losses for this purpose are the difference between the expected return calculated using the market-related value of assets and the actual return. Pension and OPEB Assets The fair value tables within Pension and OPEB Assets present the classification of assets for AEP within the fair value hierarchy. All Level 1, 2, 3 and Other amounts can be allocated to the Registrant Subsidiaries using the percentages in the table below:
|  | Pension Plan |  | OPEB
|  | December 31,
Company |  | 2023 |  | 2022 |  | 2023 |  | 2022
AEP Texas |  | 8.1 | % |  | 8.1 | % |  | 8.2 | % |  | 8.3 | %
APCo |  | 13.4 | % |  | 12.9 | % |  | 14.5 | % |  | 14.8 | %
I&M |  | 13.4 | % |  | 12.9 | % |  | 12.2 | % |  | 12.3 | %
OPCo |  | 10.2 | % |  | 9.9 | % |  | 10.6 | % |  | 10.7 | %
PSO |  | 5.4 | % |  | 5.3 | % |  | 5.4 | % |  | 5.5 | %
SWEPCo |  | 5.5 | % |  | 5.6 | % |  | 6.6 | % |  | 6.6 | %
The following table presents the classification of pension plan assets for AEP within the fair value hierarchy as of December 31, 2023:
Asset Class |  | Level 1 |  | Level 2 |  | Level 3 |  | Other |  | Total |  | Year End Allocation
|  | (in millions) |  |
Equities (a): |  |  |  |  |  |  |  |  |  |  |  |
Domestic |  | $ | 411.3 |  |  | $ | — |  |  | $ | — |  |  | $ | — |  |  | $ | 411.3 |  |  | 10.0 | %
International |  | 389.8 |  |  | — |  |  | — |  |  | — |  |  | 389.8 |  |  | 9.5 | %
Common Collective Trusts (b) |  | — |  |  | — |  |  | — |  |  | 420.9 |  |  | 420.9 |  |  | 10.2 | %
Subtotal – Equities |  | 801.1 |  |  | — |  |  | — |  |  | 420.9 |  |  | 1,222.0 |  |  | 29.7 | %
Fixed Income (a): |  |  |  |  |  |  |  |  |  |  |  |
United States Government and Agency Securities |  | 8.3 |  |  | 1,099.2 |  |  | — |  |  | — |  |  | 1,107.5 |  |  | 26.9 | %
Corporate Debt |  | — |  |  | 894.8 |  |  | — |  |  | — |  |  | 894.8 |  |  | 21.7 | %
Foreign Debt |  | — |  |  | 167.1 |  |  | — |  |  | — |  |  | 167.1 |  |  | 4.1 | %
State and Local Government |  | — |  |  | 38.7 |  |  | — |  |  | — |  |  | 38.7 |  |  | 0.9 | %
Other – Asset Backed |  | — |  |  | 1.3 |  |  | — |  |  | — |  |  | 1.3 |  |  | — | %
Subtotal – Fixed Income |  | 8.3 |  |  | 2,201.1 |  |  | — |  |  | — |  |  | 2,209.4 |  |  | 53.6 | %
Infrastructure (b) |  | — |  |  | — |  |  | — |  |  | 101.4 |  |  | 101.4 |  |  | 2.5 | %
Real Estate (b) |  | — |  |  | — |  |  | — |  |  | 239.3 |  |  | 239.3 |  |  | 5.8 | %
Alternative Investments (b) |  | — |  |  | — |  |  | — |  |  | 241.8 |  |  | 241.8 |  |  | 5.8 | %
Cash and Cash Equivalents (b) |  | — |  |  | 51.0 |  |  | — |  |  | 33.8 |  |  | 84.8 |  |  | 2.1 | %
Other – Pending Transactions and Accrued Income (c) |  | — |  |  | — |  |  | 0.1 |  |  | 19.4 |  |  | 19.5 |  |  | 0.5 | %
Total |  | $ | 809.4 |  |  | $ | 2,252.1 |  |  | $ | 0.1 |  |  | $ | 1,056.6 |  |  | $ | 4,118.2 |  |  | 100.0 | %
(a)Includes investment securities loaned to borrowers under the securities lending program. See the “Investments Held in Trust for Future Liabilities” section of Note 1 for additional information. (b)Amounts in “Other” column represent investments for which fair value is measured using net asset value per-share. (c)Amounts in “Other” column primarily represent accrued interest, dividend receivables and transactions pending settlement. The following table presents the classification of OPEB plan assets for AEP within the fair value hierarchy as of December 31, 2023:
Asset Class |  | Level 1 |  | Level 2 |  | Level 3 |  | Other |  | Total |  | Year End Allocation
|  | (in millions) |  |
Equities: |  |  |  |  |  |  |  |  |  |  |  |
Domestic |  | $ | 540.6 |  |  | $ | — |  |  | $ | — |  |  | $ | — |  |  | $ | 540.6 |  |  | 32.3 | %
International |  | 288.4 |  |  | — |  |  | — |  |  | — |  |  | 288.4 |  |  | 17.2 | %
Common Collective Trusts (a) |  | — |  |  | — |  |  | — |  |  | 131.6 |  |  | 131.6 |  |  | 7.9 | %
Subtotal – Equities |  | 829.0 |  |  | — |  |  | — |  |  | 131.6 |  |  | 960.6 |  |  | 57.4 | %
Fixed Income: |  |  |  |  |  |  |  |  |  |  |  |
Common Collective Trust – Debt (a) |  | — |  |  | — |  |  | — |  |  | 146.7 |  |  | 146.7 |  |  | 8.8 | %
United States Government and Agency Securities |  | 1.4 |  |  | 163.3 |  |  | — |  |  | — |  |  | 164.7 |  |  | 9.8 | %
Corporate Debt |  | — |  |  | 149.0 |  |  | — |  |  | — |  |  | 149.0 |  |  | 8.9 | %
Foreign Debt |  | — |  |  | 28.6 |  |  | — |  |  | — |  |  | 28.6 |  |  | 1.7 | %
State and Local Government |  | 41.5 |  |  | 7.8 |  |  | — |  |  | — |  |  | 49.3 |  |  | 3.0 | %
Other – Asset Backed |  | — |  |  | 0.2 |  |  | — |  |  | — |  |  | 0.2 |  |  | — | %
Subtotal – Fixed Income |  | 42.9 |  |  | 348.9 |  |  | — |  |  | 146.7 |  |  | 538.5 |  |  | 32.2 | %
Trust Owned Life Insurance: |  |  |  |  |  |  |  |  |  |  |  |
International Equities |  | — |  |  | 22.3 |  |  | — |  |  | — |  |  | 22.3 |  |  | 1.3 | %
United States Bonds |  | — |  |  | 130.0 |  |  | — |  |  | — |  |  | 130.0 |  |  | 7.8 | %
Subtotal – Trust Owned Life Insurance |  | — |  |  | 152.3 |  |  | — |  |  | — |  |  | 152.3 |  |  | 9.1 | %
Cash and Cash Equivalents (a) |  | 25.9 |  |  | — |  |  | — |  |  | 2.9 |  |  | 28.8 |  |  | 1.7 | %
Other – Pending Transactions and Accrued Income (b) |  | — |  |  | — |  |  | — |  |  | (6.9) |  |  | (6.9) |  |  | (0.4) | %
Total |  | $ | 897.8 |  |  | $ | 501.2 |  |  | $ | — |  |  | $ | 274.3 |  |  | $ | 1,673.3 |  |  | 100.0 | %
(a)Amounts in “Other” column represent investments for which fair value is measured using net asset value per-share. (b)Amounts in “Other” column primarily represent accrued interest, dividend receivables and transactions pending settlement. The following table presents the classification of pension plan assets for AEP within the fair value hierarchy as of December 31, 2022:
Asset Class |  | Level 1 |  | Level 2 |  | Level 3 |  | Other |  | Total |  | Year End Allocation
|  | (in millions) |  |
Equities (a): |  |  |  |  |  |  |  |  |  |  |  |
Domestic |  | $ | 347.6 |  |  | $ | — |  |  | $ | — |  |  | $ | — |  |  | $ | 347.6 |  |  | 8.4 | %
International |  | 398.4 |  |  | — |  |  | — |  |  | — |  |  | 398.4 |  |  | 9.7 | %
Common Collective Trusts (b) |  | — |  |  | — |  |  | — |  |  | 379.9 |  |  | 379.9 |  |  | 9.2 | %
Subtotal – Equities |  | 746.0 |  |  | — |  |  | — |  |  | 379.9 |  |  | 1,125.9 |  |  | 27.3 | %
Fixed Income (a): |  |  |  |  |  |  |  |  |  |  |  |
United States Government and Agency Securities |  | (0.6) |  |  | 1,071.4 |  |  | — |  |  | — |  |  | 1,070.8 |  |  | 26.0 | %
Corporate Debt |  | — |  |  | 891.7 |  |  | — |  |  | — |  |  | 891.7 |  |  | 21.6 | %
Foreign Debt |  | — |  |  | 140.2 |  |  | — |  |  | — |  |  | 140.2 |  |  | 3.4 | %
State and Local Government |  | — |  |  | 37.0 |  |  | — |  |  | — |  |  | 37.0 |  |  | 0.9 | %
Other – Asset Backed |  | — |  |  | 0.8 |  |  | — |  |  | — |  |  | 0.8 |  |  | — | %
Subtotal – Fixed Income |  | (0.6) |  |  | 2,141.1 |  |  | — |  |  | — |  |  | 2,140.5 |  |  | 51.9 | %
Infrastructure (b) |  | — |  |  | — |  |  | — |  |  | 109.2 |  |  | 109.2 |  |  | 2.6 | %
Real Estate (b) |  | — |  |  | — |  |  | — |  |  | 276.9 |  |  | 276.9 |  |  | 6.7 | %
Alternative Investments (b) |  | — |  |  | — |  |  | — |  |  | 319.7 |  |  | 319.7 |  |  | 7.8 | %
Cash and Cash Equivalents (b) |  | — |  |  | 64.9 |  |  | — |  |  | 58.3 |  |  | 123.2 |  |  | 3.0 | %
Other – Pending Transactions and Accrued Income (c) |  | — |  |  | — |  |  | — |  |  | 29.3 |  |  | 29.3 |  |  | 0.7 | %
Total |  | $ | 745.4 |  |  | $ | 2,206.0 |  |  | $ | — |  |  | $ | 1,173.3 |  |  | $ | 4,124.7 |  |  | 100.0 | %
(a)Includes investment securities loaned to borrowers under the securities lending program. See the “Investments Held in Trust for Future Liabilities” section of Note 1 for additional information. (b)Amounts in “Other” column represent investments for which fair value is measured using net asset value per-share. (c)Amounts in “Other” column primarily represent accrued interest, dividend receivables and transactions pending settlement. The following table presents the classification of OPEB plan assets for AEP within the fair value hierarchy as of December 31, 2022:
Asset Class |  | Level 1 |  | Level 2 |  | Level 3 |  | Other |  | Total |  | Year End Allocation
|  | (in millions) |  |
Equities: |  |  |  |  |  |  |  |  |  |  |  |
Domestic |  | $ | 414.1 |  |  | $ | — |  |  | $ | — |  |  | $ | — |  |  | $ | 414.1 |  |  | 26.7 | %
International |  | 265.0 |  |  | — |  |  | — |  |  | — |  |  | 265.0 |  |  | 17.1 | %
Common Collective Trusts (a) |  | — |  |  | — |  |  | — |  |  | 169.1 |  |  | 169.1 |  |  | 10.9 | %
Subtotal – Equities |  | 679.1 |  |  | — |  |  | — |  |  | 169.1 |  |  | 848.2 |  |  | 54.7 | %
Fixed Income: |  |  |  |  |  |  |  |  |  |  |  |
Common Collective Trust – Debt (a) |  | — |  |  | — |  |  | — |  |  | 120.3 |  |  | 120.3 |  |  | 7.8 | %
United States Government and Agency Securities |  | 0.1 |  |  | 155.8 |  |  | — |  |  | — |  |  | 155.9 |  |  | 10.1 | %
Corporate Debt |  | — |  |  | 141.5 |  |  | — |  |  | — |  |  | 141.5 |  |  | 9.1 | %
Foreign Debt |  | — |  |  | 21.0 |  |  | — |  |  | — |  |  | 21.0 |  |  | 1.4 | %
State and Local Government |  | 62.9 |  |  | 7.8 |  |  | — |  |  | — |  |  | 70.7 |  |  | 4.6 | %
Subtotal – Fixed Income |  | 63.0 |  |  | 326.1 |  |  | — |  |  | 120.3 |  |  | 509.4 |  |  | 33.0 | %
Trust Owned Life Insurance: |  |  |  |  |  |  |  |  |  |  |  |
International Equities |  | — |  |  | 46.7 |  |  | — |  |  | — |  |  | 46.7 |  |  | 3.0 | %
United States Bonds |  | — |  |  | 110.3 |  |  | — |  |  | — |  |  | 110.3 |  |  | 7.1 | %
Subtotal – Trust Owned Life Insurance |  | — |  |  | 157.0 |  |  | — |  |  | — |  |  | 157.0 |  |  | 10.1 | %
Cash and Cash Equivalents (a) |  | 23.2 |  |  | — |  |  | — |  |  | 6.7 |  |  | 29.9 |  |  | 1.9 | %
Other – Pending Transactions and Accrued Income (b) |  | — |  |  | — |  |  | — |  |  | 4.8 |  |  | 4.8 |  |  | 0.3 | %
Total |  | $ | 765.3 |  |  | $ | 483.1 |  |  | $ | — |  |  | $ | 300.9 |  |  | $ | 1,549.3 |  |  | 100.0 | %
(a)Amounts in “Other” column represent investments for which fair value is measured using net asset value per-share. (b)Amounts in “Other” column primarily represent accrued interest, dividend receivables and transactions pending settlement. Accumulated Benefit Obligation The accumulated benefit obligation for the pension plans is as follows:
Accumulated Benefit Obligation |  | AEP |  | AEP Texas |  | APCo |  | I&M |  | OPCo |  | PSO |  | SWEPCo
|  | (in millions)
Qualified Pension Plan |  | $ | 3,878.7 |  |  | $ | 321.1 |  |  | $ | 485.6 |  |  | $ | 450.3 |  |  | $ | 354.0 |  |  | $ | 186.6 |  |  | $ | 241.9 |
Nonqualified Pension Plans |  | 54.8 |  |  | 2.1 |  |  | 0.1 |  |  | 0.7 |  |  | 0.1 |  |  | 1.2 |  |  | 1.0 |
Total as of December 31, 2023 |  | $ | 3,933.5 |  |  | $ | 323.2 |  |  | $ | 485.7 |  |  | $ | 451.0 |  |  | $ | 354.1 |  |  | $ | 187.8 |  |  | $ | 242.9 |
Accumulated Benefit Obligation |  | AEP |  | AEP Texas |  | APCo |  | I&M |  | OPCo |  | PSO |  | SWEPCo
|  | (in millions)
Qualified Pension Plan |  | $ | 3,827.4 |  |  | $ | 315.4 |  |  | $ | 470.1 |  |  | $ | 443.8 |  |  | $ | 344.1 |  |  | $ | 179.1 |  |  | $ | 234.0 |
Nonqualified Pension Plans |  | 55.6 |  |  | 2.5 |  |  | 0.3 |  |  | 1.2 |  |  | 0.1 |  |  | 1.2 |  |  | 1.1 |
Total as of December 31, 2022 |  | $ | 3,883.0 |  |  | $ | 317.9 |  |  | $ | 470.4 |  |  | $ | 445.0 |  |  | $ | 344.2 |  |  | $ | 180.3 |  |  | $ | 235.1 |
Obligations in Excess of Fair Values The tables below show the underfunded pension plans that had obligations in excess of plan assets. Projected Benefit Obligation
| AEP |  | AEP Texas |  | APCo |  | I&M |  | OPCo |  | PSO |  | SWEPCo
| (in millions)
Projected Benefit Obligation | $ | 60.7 |  |  | $ | 343.1 |  |  | $ | 0.4 |  |  | $ | 1.2 |  |  | $ | 0.3 |  |  | $ | 1.4 |  |  | $ | 261.2 |
Fair Value of Plan Assets | — |  |  | 332.7 |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 227.5 |
Underfunded Projected Benefit Obligation as of December 31, 2023 | $ | (60.7) |  |  | $ | (10.4) |  |  | $ | (0.4) |  |  | $ | (1.2) |  |  | $ | (0.3) |  |  | $ | (1.4) |  |  | $ | (33.7) |
| AEP |  | AEP Texas |  | APCo |  | I&M |  | OPCo |  | PSO |  | SWEPCo
| (in millions)
Projected Benefit Obligation | $ | 61.5 |  |  | $ | 2.7 |  |  | $ | 0.6 |  |  | $ | 1.6 |  |  | $ | 0.3 |  |  | $ | 1.5 |  |  | $ | 250.7 |
Fair Value of Plan Assets | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 231.3 |
Underfunded Projected Benefit Obligation as of December 31, 2022 | $ | (61.5) |  |  | $ | (2.7) |  |  | $ | (0.6) |  |  | $ | (1.6) |  |  | $ | (0.3) |  |  | $ | (1.5) |  |  | $ | (19.4) |
Accumulated Benefit Obligation
| AEP |  | AEP Texas |  | APCo |  | I&M |  | OPCo |  | PSO |  | SWEPCo
| (in millions)
Accumulated Benefit Obligation | $ | 54.8 |  |  | $ | 2.1 |  |  | $ | 0.1 |  |  | $ | 0.7 |  |  | $ | 0.1 |  |  | $ | 1.2 |  |  | $ | 242.9 |
Fair Value of Plan Assets | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 227.5 |
Underfunded Accumulated Benefit Obligation as of December 31, 2023 | $ | (54.8) |  |  | $ | (2.1) |  |  | $ | (0.1) |  |  | $ | (0.7) |  |  | $ | (0.1) |  |  | $ | (1.2) |  |  | $ | (15.4) |
| AEP |  | AEP Texas |  | APCo |  | I&M |  | OPCo |  | PSO |  | SWEPCo
| (in millions)
Accumulated Benefit Obligation | $ | 55.6 |  |  | $ | 2.5 |  |  | $ | 0.3 |  |  | $ | 1.2 |  |  | $ | 0.1 |  |  | $ | 1.2 |  |  | $ | 235.1 |
Fair Value of Plan Assets | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 231.3 |
Underfunded Accumulated Benefit Obligation as of December 31, 2022 | $ | (55.6) |  |  | $ | (2.5) |  |  | $ | (0.3) |  |  | $ | (1.2) |  |  | $ | (0.1) |  |  | $ | (1.2) |  |  | $ | (3.8) |
Estimated Future Benefit Payments and Contributions The estimated pension benefit payments and contributions to the trust are at least the minimum amount required by the Employee Retirement Income Security Act plus payment of unfunded non-qualified benefits. For the qualified pension plan, additional discretionary contributions may also be made to maintain the funded status of the plan. For OPEB plans, expected payments include the payment of unfunded benefits. The following table provides the estimated contributions and payments by Registrant for 2024:
|  | AEP |  | AEP Texas |  | APCo |  | I&M |  | OPCo |  | PSO |  | SWEPCo
|  | (in millions)
Pension Plans |  | $ | 6.7 |  |  | $ | 0.3 |  |  | $ | — |  |  | $ | — |  |  | $ | — |  |  | $ | 0.1 |  |  | $ | 0.1 |
OPEB |  | 3.0 |  |  | — |  |  | 1.6 |  |  | — |  |  | — |  |  | — |  |  | — |
The tables below reflect the total benefits expected to be paid from the plan or from the Registrants’ assets. The payments include the participants’ contributions to the plan for their share of the cost. Future benefit payments are dependent on the number of employees retiring, whether the retiring employees elect to receive pension benefits as annuities or as lump sum distributions, future integration of the benefit plans with changes to Medicare and other legislation, future levels of interest rates and variances in actuarial results. The estimated payments for the pension benefits and OPEB are as follows:
Pension Plans |  | AEP |  | AEP Texas |  | APCo |  | I&M |  | OPCo |  | PSO |  | SWEPCo
|  | (in millions)
2024 |  | $ | 369.5 |  |  | $ | 36.7 |  |  | $ | 43.9 |  |  | $ | 39.0 |  |  | $ | 32.6 |  |  | $ | 19.7 |  |  | $ | 24.4 |
2025 |  | 361.8 |  |  | 34.3 |  |  | 43.3 |  |  | 39.7 |  |  | 32.7 |  |  | 19.2 |  |  | 25.8 |
2026 |  | 365.7 |  |  | 34.5 |  |  | 44.1 |  |  | 39.7 |  |  | 32.5 |  |  | 19.4 |  |  | 26.1 |
2027 |  | 361.9 |  |  | 32.2 |  |  | 42.6 |  |  | 39.8 |  |  | 32.4 |  |  | 19.3 |  |  | 25.3 |
2028 |  | 357.8 |  |  | 32.2 |  |  | 43.5 |  |  | 39.4 |  |  | 31.3 |  |  | 19.0 |  |  | 23.7 |
Years 2029 to 2033, in Total |  | 1,657.6 |  |  | 133.5 |  |  | 200.0 |  |  | 189.4 |  |  | 144.5 |  |  | 81.0 |  |  | 105.6 |
OPEB Benefit Payments |  | AEP |  | AEP Texas |  | APCo |  | I&M |  | OPCo |  | PSO |  | SWEPCo
|  | (in millions)
2024 |  | $ | 117.2 |  |  | $ | 9.4 |  |  | $ | 18.8 |  |  | $ | 15.2 |  |  | $ | 12.6 |  |  | $ | 6.7 |  |  | $ | 7.8 |
2025 |  | 122.6 |  |  | 10.0 |  |  | 19.4 |  |  | 15.7 |  |  | 13.0 |  |  | 7.1 |  |  | 8.3 |
2026 |  | 122.4 |  |  | 10.2 |  |  | 19.3 |  |  | 15.7 |  |  | 12.8 |  |  | 7.0 |  |  | 8.3 |
2027 |  | 121.5 |  |  | 10.2 |  |  | 19.1 |  |  | 15.4 |  |  | 12.7 |  |  | 6.8 |  |  | 8.1 |
2028 |  | 120.2 |  |  | 9.9 |  |  | 19.0 |  |  | 15.0 |  |  | 12.5 |  |  | 6.5 |  |  | 8.2 |
Years 2029 to 2033, in Total |  | 566.1 |  |  | 45.2 |  |  | 88.3 |  |  | 69.7 |  |  | 57.6 |  |  | 30.2 |  |  | 38.8 |
OPEB Medicare Subsidy Receipts |  | AEP |  | AEP Texas |  | APCo |  | I&M |  | OPCo |  | PSO |  | SWEPCo
|  | (in millions)
2024 |  | $ | 0.3 |  |  | $ | — |  |  | $ | 0.1 |  |  | $ | — |  |  | $ | — |  |  | $ | — |  |  | $ | — |
2025 |  | 0.3 |  |  | — |  |  | 0.1 |  |  | — |  |  | — |  |  | — |  |  | — |
2026 |  | 0.3 |  |  | — |  |  | 0.1 |  |  | — |  |  | — |  |  | — |  |  | — |
2027 |  | 0.3 |  |  | — |  |  | 0.1 |  |  | — |  |  | — |  |  | — |  |  | — |
2028 |  | 0.3 |  |  | — |  |  | 0.1 |  |  | — |  |  | — |  |  | — |  |  | — |
Years 2029 to 2033, in Total |  | 1.5 |  |  | — |  |  | 0.5 |  |  | — |  |  | — |  |  | — |  |  | — |
Components of Net Periodic Benefit Cost The following tables provide the components of net periodic benefit cost (credit) by Registrant for the plans: Pension Plans
2023 |  | AEP |  | AEP Texas |  | APCo |  | I&M |  | OPCo |  | PSO |  | SWEPCo
|  | (in millions)
Service Cost |  | $ | 94.3 |  |  | $ | 8.2 |  |  | $ | 9.1 |  |  | $ | 11.9 |  |  | $ | 8.4 |  |  | $ | 5.5 |  |  | $ | 7.7 |
Interest Cost |  | 219.2 |  |  | 18.3 |  |  | 26.4 |  |  | 24.9 |  |  | 19.8 |  |  | 10.7 |  |  | 13.9 |
Expected Return on Plan Assets |  | (339.2) |  |  | (28.1) |  |  | (44.6) |  |  | (44.2) |  |  | (34.0) |  |  | (18.3) |  |  | (19.4) |
Amortization of Net Actuarial Loss |  | 1.4 |  |  | 0.1 |  |  | — |  |  | 0.1 |  |  | — |  |  | — |  |  | 0.1 |
Net Periodic Benefit Cost (Credit) |  | (24.3) |  |  | (1.5) |  |  | (9.1) |  |  | (7.3) |  |  | (5.8) |  |  | (2.1) |  |  | 2.3 |
Capitalized Portion |  | (43.6) |  |  | (4.7) |  |  | (4.2) |  |  | (3.6) |  |  | (4.7) |  |  | (2.5) |  |  | (3.0) |
Net Periodic Benefit Credit Recognized in Expense |  | $ | (67.9) |  |  | $ | (6.2) |  |  | $ | (13.3) |  |  | $ | (10.9) |  |  | $ | (10.5) |  |  | $ | (4.6) |  |  | $ | (0.7) |
2022 |  | AEP |  | AEP Texas |  | APCo |  | I&M |  | OPCo |  | PSO |  | SWEPCo
|  | (in millions)
Service Cost |  | $ | 123.1 |  |  | $ | 11.1 |  |  | $ | 11.4 |  |  | $ | 16.2 |  |  | $ | 11.2 |  |  | $ | 7.4 |  |  | $ | 10.6 |
Interest Cost |  | 148.2 |  |  | 12.1 |  |  | 17.5 |  |  | 17.0 |  |  | 13.3 |  |  | 7.0 |  |  | 9.1 |
Expected Return on Plan Assets |  | (253.4) |  |  | (21.0) |  |  | (32.3) |  |  | (32.4) |  |  | (24.8) |  |  | (13.4) |  |  | (14.6) |
Amortization of Net Actuarial Loss |  | 63.0 |  |  | 5.2 |  |  | 7.4 |  |  | 7.1 |  |  | 5.5 |  |  | 2.9 |  |  | 3.8 |
Net Periodic Benefit Cost |  | 80.9 |  |  | 7.4 |  |  | 4.0 |  |  | 7.9 |  |  | 5.2 |  |  | 3.9 |  |  | 8.9 |
Capitalized Portion |  | (53.8) |  |  | (6.2) |  |  | (5.0) |  |  | (4.6) |  |  | (6.1) |  |  | (3.2) |  |  | (4.0) |
Net Periodic Benefit Cost (Credit) Recognized in Expense |  | $ | 27.1 |  |  | $ | 1.2 |  |  | $ | (1.0) |  |  | $ | 3.3 |  |  | $ | (0.9) |  |  | $ | 0.7 |  |  | $ | 4.9 |
2021 |  | AEP |  | AEP Texas |  | APCo |  | I&M |  | OPCo |  | PSO |  | SWEPCo
|  | (in millions)
Service Cost |  | $ | 129.2 |  |  | $ | 11.8 |  |  | $ | 11.9 |  |  | $ | 17.5 |  |  | $ | 11.4 |  |  | $ | 8.0 |  |  | $ | 11.2 |
Interest Cost |  | 137.2 |  |  | 11.2 |  |  | 16.4 |  |  | 16.2 |  |  | 12.5 |  |  | 6.7 |  |  | 8.5 |
Expected Return on Plan Assets |  | (229.7) |  |  | (19.5) |  |  | (29.1) |  |  | (28.9) |  |  | (22.3) |  |  | (12.3) |  |  | (13.5) |
Amortization of Net Actuarial Loss |  | 101.5 |  |  | 8.3 |  |  | 12.0 |  |  | 11.7 |  |  | 9.1 |  |  | 4.9 |  |  | 6.2 |
Net Periodic Benefit Cost |  | 138.2 |  |  | 11.8 |  |  | 11.2 |  |  | 16.5 |  |  | 10.7 |  |  | 7.3 |  |  | 12.4 |
Capitalized Portion |  | (55.7) |  |  | (6.6) |  |  | (5.2) |  |  | (4.9) |  |  | (6.2) |  |  | (3.4) |  |  | (4.1) |
Net Periodic Benefit Cost Recognized in Expense |  | $ | 82.5 |  |  | $ | 5.2 |  |  | $ | 6.0 |  |  | $ | 11.6 |  |  | $ | 4.5 |  |  | $ | 3.9 |  |  | $ | 8.3 |
OPEB
2023 |  | AEP |  | AEP Texas |  | APCo |  | I&M |  | OPCo |  | PSO |  | SWEPCo
|  | (in millions)
Service Cost |  | $ | 4.6 |  |  | $ | 0.3 |  |  | $ | 0.5 |  |  | $ | 0.6 |  |  | $ | 0.4 |  |  | $ | 0.3 |  |  | $ | 0.4 |
Interest Cost |  | 46.2 |  |  | 3.6 |  |  | 7.4 |  |  | 5.4 |  |  | 4.7 |  |  | 2.4 |  |  | 2.9 |
Expected Return on Plan Assets |  | (109.6) |  |  | (9.0) |  |  | (16.1) |  |  | (13.5) |  |  | (11.8) |  |  | (5.9) |  |  | (7.2) |
Amortization of Prior Service Credit |  | (63.1) |  |  | (5.3) |  |  | (9.2) |  |  | (8.7) |  |  | (6.3) |  |  | (4.0) |  |  | (4.9) |
Amortization of Net Actuarial Loss |  | 14.8 |  |  | 1.2 |  |  | 2.3 |  |  | 1.9 |  |  | 1.6 |  |  | 0.8 |  |  | 1.0 |
Net Periodic Benefit Credit |  | (107.1) |  |  | (9.2) |  |  | (15.1) |  |  | (14.3) |  |  | (11.4) |  |  | (6.4) |  |  | (7.8) |
Capitalized Portion |  | (2.1) |  |  | (0.2) |  |  | (0.2) |  |  | (0.2) |  |  | (0.2) |  |  | (0.1) |  |  | (0.2) |
Net Periodic Benefit Credit Recognized in Expense |  | $ | (109.2) |  |  | $ | (9.4) |  |  | $ | (15.3) |  |  | $ | (14.5) |  |  | $ | (11.6) |  |  | $ | (6.5) |  |  | $ | (8.0) |
2022 |  | AEP |  | AEP Texas |  | APCo |  | I&M |  | OPCo |  | PSO |  | SWEPCo
|  | (in millions)
Service Cost |  | $ | 7.4 |  |  | $ | 0.5 |  |  | $ | 0.8 |  |  | $ | 0.9 |  |  | $ | 0.6 |  |  | $ | 0.4 |  |  | $ | 0.6 |
Interest Cost |  | 29.2 |  |  | 2.2 |  |  | 4.7 |  |  | 3.4 |  |  | 3.0 |  |  | 1.5 |  |  | 1.8 |
Expected Return on Plan Assets |  | (110.0) |  |  | (9.1) |  |  | (16.3) |  |  | (13.7) |  |  | (12.0) |  |  | (6.1) |  |  | (7.3) |
Amortization of Prior Service Credit |  | (71.4) |  |  | (6.1) |  |  | (10.4) |  |  | (9.7) |  |  | (7.1) |  |  | (4.4) |  |  | (5.3) |
Net Periodic Benefit Credit |  | (144.8) |  |  | (12.5) |  |  | (21.2) |  |  | (19.1) |  |  | (15.5) |  |  | (8.6) |  |  | (10.2) |
Capitalized Portion |  | (3.2) |  |  | (0.3) |  |  | (0.4) |  |  | (0.3) |  |  | (0.3) |  |  | (0.2) |  |  | (0.2) |
Net Periodic Benefit Credit Recognized in Expense |  | $ | (148.0) |  |  | $ | (12.8) |  |  | $ | (21.6) |  |  | $ | (19.4) |  |  | $ | (15.8) |  |  | $ | (8.8) |  |  | $ | (10.4) |
2021 |  | AEP |  | AEP Texas |  | APCo |  | I&M |  | OPCo |  | PSO |  | SWEPCo
|  | (in millions)
Service Cost |  | $ | 9.5 |  |  | $ | 0.7 |  |  | $ | 1.0 |  |  | $ | 1.3 |  |  | $ | 0.8 |  |  | $ | 0.6 |  |  | $ | 0.8 |
Interest Cost |  | 30.5 |  |  | 2.4 |  |  | 4.9 |  |  | 3.5 |  |  | 3.0 |  |  | 1.6 |  |  | 1.9 |
Expected Return on Plan Assets |  | (91.1) |  |  | (7.5) |  |  | (13.5) |  |  | (11.1) |  |  | (9.7) |  |  | (5.0) |  |  | (6.1) |
Amortization of Prior Service Credit |  | (70.9) |  |  | (6.0) |  |  | (10.3) |  |  | (9.6) |  |  | (7.2) |  |  | (4.4) |  |  | (5.3) |
Net Periodic Benefit Credit |  | (122.0) |  |  | (10.4) |  |  | (17.9) |  |  | (15.9) |  |  | (13.1) |  |  | (7.2) |  |  | (8.7) |
Capitalized Portion |  | (4.1) |  |  | (0.4) |  |  | (0.4) |  |  | (0.4) |  |  | (0.4) |  |  | (0.3) |  |  | (0.3) |
Net Periodic Benefit Credit Recognized in Expense |  | $ | (126.1) |  |  | $ | (10.8) |  |  | $ | (18.3) |  |  | $ | (16.3) |  |  | $ | (13.5) |  |  | $ | (7.5) |  |  | $ | (9.0) |
American Electric Power System Retirement Savings Plan AEPSC sponsors the American Electric Power System Retirement Savings Plan, a defined contribution retirement savings plan for substantially all AEP subsidiary employees who are not covered by a retirement savings plan of the UMWA. This qualified plan offers participants an opportunity to contribute a portion of their pay, includes features under Section 401(k) of the Internal Revenue Code and provides for company matching contributions. The matching contributions to the plan are 100% of the first 1% of eligible employee contributions and 70% of the next 5% of contributions. The following table provides the cost for matching contributions to the retirement savings plans by Registrant:
Year Ended December 31, |  | AEP |  | AEP Texas |  | APCo |  | I&M |  | OPCo |  | PSO |  | SWEPCo
|  | (in millions)
2023 |  | $ | 87.9 |  |  | $ | 7.1 |  |  | $ | 8.4 |  |  | $ | 11.0 |  |  | $ | 8.2 |  |  | $ | 5.3 |  |  | $ | 6.7 |
2022 |  | 81.9 |  |  | 6.5 |  |  | 7.8 |  |  | 11.1 |  |  | 7.7 |  |  | 4.7 |  |  | 6.4 |
2021 |  | 79.9 |  |  | 6.4 |  |  | 7.6 |  |  | 10.9 |  |  | 7.2 |  |  | 4.6 |  |  | 6.4 |
UMWA Benefits Health and Welfare Benefits (Applies to AEP and APCo) AEP provides health and welfare benefits negotiated with the UMWA for certain unionized employees, retirees and their survivors who meet eligibility requirements. APCo also provides the same UMWA health and welfare benefits for certain unionized mining retirees and their survivors who meet eligibility requirements. AEP and APCo administer the health and welfare benefits and pay them from their general assets. Multiemployer Pension Benefits (Applies to AEP) UMWA pension benefits are provided through the United Mine Workers of America 1974 Pension Plan (Employer Identification Number: 52-1050282, Plan Number 002), a multiemployer plan. The UMWA pension benefits are administered by a board of trustees appointed in equal numbers by the UMWA and the Bituminous Coal Operators’ Association (BCOA), an industry bargaining association. AEP makes contributions to the United Mine Workers of America 1974 Pension Plan based on provisions in its labor agreement and the plan documents. The UMWA pension plan is different from single-employer plans as an employer’s contributions may be used to provide benefits to employees of other participating employers. A withdrawing employer may be subject to a withdrawal liability, which is calculated based upon that employer’s share of the plan’s unfunded benefit obligations. If an employer fails to make required contributions or if its payments in connection with its withdrawal liability fall short of satisfying its share of the plan’s unfunded benefit obligations, the remaining employers may be allocated a greater share of the remaining unfunded plan obligations. Under the Pension Protection Act of 2006 (PPA), the UMWA pension plan is in Critical Status for the plan year beginning July 1, 2023 and was in Critical Status for the plan year beginning July 1, 2022. As required under the PPA, the Plan adopted a Rehabilitation Plan in 2015. The Rehabilitation Plan has been updated annually, most recently in April 2023. AEP affiliates contributed $396 thousand, $329 thousand and $339 thousand to the United Mine Workers of America 1974 Pension Plan for the years ended December 31, 2023, 2022 and 2021, respectively. The contributions did not include surcharges. An AEP affiliate, Cook Coal Terminal (CCT), was listed in the plan’s 2021 Form 5500 as providing more than 5 percent of the total contributions for the plan year ending June 30, 2022. The plan’s 2022 Form 5500 is expected to be filed in the second quarter of 2024. Under the terms of the UMWA pension plan, contributions will be required to continue beyond the January 25, 2025 expiration of the current collective bargaining agreement between the CCT facility and the UMWA, whether or not the term of that agreement is extended or a subsequent agreement is entered, so long as both the UMWA pension plan remains in effect and an AEP affiliate continues to operate the facility covered by the current collective bargaining agreement. The contribution rate applicable would be determined in accordance with the terms of the UMWA pension plan by reference to the National Bituminous Coal Wage Agreement, subject to periodic revisions, between the UMWA and the BCOA. If the UMWA pension plan would terminate or an AEP affiliate would cease operation of the facility without arranging for a successor operator to assume its liability, the withdrawal liability obligation would be triggered. AEP records a UMWA pension withdrawal liability on the balance sheet that is re-measured annually and is the estimated value of the company’s anticipated contributions toward its proportionate share of the plan’s unfunded vested liabilities. As of December 31, 2023 and 2022, the liability balance was $13 million and $12 million, respectively. AEP recovers the estimated value of its UMWA pension withdrawal liability through fuel clauses in certain regulated jurisdictions. AEP records a regulatory asset on the balance sheets when the UMWA pension withdrawal liability exceeds the cumulative billings collected and a regulatory liability on the balance sheets when the cumulative billings collected exceed the withdrawal liability. If any portion of the UMWA pension withdrawal liability is not recoverable, it could reduce future net income and cash flows and impact financial condition.

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