X0407 4 2023-03-31 0 0000929008 WESCO INTERNATIONAL INC WCC 0001498509 NAGARAJAN SUNDARAM 225 WEST STATION SQUARE DRIVE SUITE 700 PITTSBURGH PA 15219-1122 1 0 0 0 0 Common Stock 2023-03-31 4 A 0 4.9623 0.00 A 2049.2141 D Common Stock 2023-03-31 4 A 0 194.124 0.00 A 2243.3381 D Represents dividend equivalent rights ("DERs") in connection with the Issuer's quarterly dividend and accrued to the Reporting Person on restricted stock units held by the Reporting Person. These DERs vest on the same schedules as the underlying awards. Deferred share units ("DSUs") are credited to the Reporting Person's deferred compensation account pursuant to the Issuer's Deferred Compensation Plan for Non-Employee Directors (the "Plan"). Each DSU is the economic equivalent of one share of Issuer's common stock and is eligible for distribution in the form of Issuer's common stock based on the schedule elected by the Reporting Person in accordance with the Plan. /s/ Michele Nelson, as Attorney-in-Fact 2023-04-04