CLASSES OF SERVICE The principal classes of service from which AEP’s subsidiaries derive revenues and the amount of such revenues during the years ended December 31, 2020, 2019 and 2018 are as follows: 5 Years Ended December 31, Description 2020 2019 2018 (in millions) Vertically Integrated Utilities Segment Retail Revenues Residential Sales $ 3,614.8  $ 3,641.2  $ 3,818.6  Commercial Sales 2,021.0  2,151.1  2,223.7  Industrial Sales 2,023.5  2,178.3  2,261.3  PJM Net Charges (0.1) (0.2) 0.4  Other Retail Sales 155.9  179.4  186.8  Total Retail Revenues 7,815.1  8,149.8  8,490.8  Wholesale Revenues Off-system Sales 589.3  814.5  888.0  Transmission 249.5  200.7  263.7  Total Wholesale Revenues 838.8  1,015.2  1,151.7  Other Electric Revenues 85.8  93.8  93.7  Provision for Rate Refund (21.7) (44.7) (210.1) Other Operating Revenues 35.2  31.6  30.6  Sales to Affiliates 126.2  121.4  88.8  Total Revenues Vertically Integrated Utilities Segment $ 8,879.4  $ 9,367.1  $ 9,645.5  Transmission and Distribution Utilities Segment Retail Revenues Residential Sales $ 2,114.9  $ 2,084.5  $ 2,213.6  Commercial Sales 1,049.5  1,148.8  1,266.7  Industrial Sales 390.0  426.5  517.2  Other Retail Sales 42.5  43.7  43.1  Total Retail Revenues 3,596.9  3,703.5  4,040.6  Wholesale Revenues Off-system Sales 60.6  93.0  119.3  Transmission 471.8  437.7  394.7  Total Wholesale Revenues 532.4  530.7  514.0  Other Electric Revenues 95.0  58.6  54.5  Provision for Rate Refund 2.3  12.5  (69.2) Other Operating Revenues 12.1  13.7  12.4  Sales to Affiliates 107.2  163.5  100.8  Total Revenues Transmission and Distribution Utilities Segment $ 4,345.9  $ 4,482.5  $ 4,653.1  AEP Transmission Holdco Segment Transmission Revenues $ 315.1  $ 265.1  $ 291.3  Other Electric Revenues 0.4  0.3  0.3  Other Operating Revenues 0.6  0.1  0.3  Sales to Affiliates 901.4  812.9  555.5  Provision for Rate Refund (18.7) (5.2) (43.3) Total Revenues AEP Transmission Holdco Segment $ 1,198.8  $ 1,073.2  $ 804.1  Generation & Marketing Segment Generation Revenues - Nonaffiliated $ 136.4  $ 264.4  $ 431.5  Renewable Generation - Nonaffiliated 85.7  77.7  44.5  Retail, Trading and Marketing Affiliated 104.6  135.7  122.2  Nonaffiliated 1,398.9  1,379.8  1,342.1  Total Revenues Generation & Marketing Segment $ 1,725.6  $ 1,857.6  $ 1,940.3 