OPCo Pension Plans OPEB Years Ended December 31, 2020 2019 2018 2020 2019 2018 (in millions) Service Cost $ 9.7  $ 7.9  $ 7.7  $ 0.9  $ 0.8  $ 0.9  Interest Cost 15.4  19.1  17.7  4.2  5.5  5.1  Expected Return on Plan Assets (26.3) (29.3) (28.8) (10.5) (10.8) (11.7) Amortization of Prior Service Credit —  —  —  (7.0) (6.9) (6.9) Amortization of Net Actuarial Loss 8.5  5.3  8.0  0.7  2.5  1.1  Net Periodic Benefit Cost (Credit) 7.3  3.0  4.6  (11.7) (8.9) (11.5) Capitalized Portion (5.0) (3.7) (3.6) (0.5) (0.4) (0.4) Net Periodic Benefit Cost (Credit) Recognized in Expense $ 2.3  $ (0.7) $ 1.0  $ (12.2) $ (9.3) $ (11.9) PSO Pension Plans OPEB Years Ended December 31, 2020 2019 2018 2020 2019 2018 (in millions) Service Cost $ 7.3  $ 6.5  $ 7.0  $ 0.7  $ 0.6  $ 0.7  Interest Cost 8.5  10.6  9.9  2.1  2.6  2.5  Expected Return on Plan Assets (14.5) (16.3) (16.1) (5.2) (5.1) (5.6) Amortization of Prior Service Credit —  —  —  (4.4) (4.3) (4.3) Amortization of Net Actuarial Loss 4.7  2.9  4.4  0.3  1.2  0.5  Net Periodic Benefit Cost (Credit) 6.0  3.7  5.2  (6.5) (5.0) (6.2) Capitalized Portion (2.8) (2.4) (2.6) (0.3) (0.2) (0.3) Net Periodic Benefit Cost (Credit) Recognized in Expense $ 3.2  $ 1.3  $ 2.6  $ (6.8) $ (5.2) $ (6.5) SWEPCo Pension Plans OPEB Years Ended December 31, 2020 2019 2018 2020 2019 2018 (in millions) Service Cost $ 9.9  $ 8.6  $ 9.3  $ 0.8  $ 0.8  $ 0.9  Interest Cost 10.2  12.4  11.3  2.5  3.1  2.8  Expected Return on Plan Assets (15.7) (17.7) (17.3) (6.3) (5.9) (6.4) Amortization of Prior Service Credit —  —  —  (5.2) (5.2) (5.2) Amortization of Net Actuarial Loss 5.7  3.4  5.1  0.4  1.4  0.6  Settlements —  —  0.4  —  —  —  Net Periodic Benefit Cost (Credit) 10.1  6.7  8.8  (7.8) (5.8) (7.3) Capitalized Portion (3.4) (2.9) (3.1) (0.3) (0.3) (0.3) Net Periodic Benefit Cost (Credit) Recognized in Expense $ 6.7  $ 3.8  $ 5.7  $ (8.1) $ (6.1) $ (7.6) American Electric Power System Retirement Savings Plan AEP sponsors the American Electric Power System Retirement Savings Plan, a defined contribution retirement savings plan for substantially all 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. 313