PUBLIC SERVICE COMPANY OF OKLAHOMA STATEMENTS OF CHANGES IN COMMON SHAREHOLDER’S EQUITY For the Years Ended December 31, 2020, 2019 and 2018 (in millions) Common Stock Paid-in Capital Retained Earnings Accumulated Other Comprehensive Income (Loss) Total TOTAL COMMON SHAREHOLDER’S EQUITY – DECEMBER 31, 2017 $ 157.2  $ 364.0  $ 691.5  $ 2.6  $ 1,215.3  Common Stock Dividends (50.0) (50.0) ASU 2018-02 Adoption 0.5  0.5  Net Income 83.2  83.2  Other Comprehensive Loss (1.0) (1.0) TOTAL COMMON SHAREHOLDER’S EQUITY – DECEMBER 31, 2018 157.2  364.0  724.7  2.1  1,248.0  Common Stock Dividends (11.3) (11.3) Net Income 137.6  137.6  Other Comprehensive Loss (1.0) (1.0) TOTAL COMMON SHAREHOLDER’S EQUITY – DECEMBER 31, 2019 157.2  364.0  851.0  1.1  1,373.3  Capital Contribution of Radial Assets from Parent 50.0  50.0  ASU 2016-13 Adoption 0.3  0.3  Net Income 123.0  123.0  Other Comprehensive Loss (1.0) (1.0) TOTAL COMMON SHAREHOLDER’S EQUITY – DECEMBER 31, 2020 $ 157.2  $ 414.0  $ 974.3  $ 0.1  $ 1,545.6  See Notes to Financial Statements of Registrants beginning on page 229. 211