X0306 4 2018-12-07 0001097864 ON SEMICONDUCTOR CORP ON 0001741144 HOPKIN VINCE CRAIG 5005 EAST MCDOWELL ROAD PHOENIX AZ 85008 1 EVP & GM, ASG Common 2018-12-07 4 F 0 524.0000 17.3700 D 82545.0000 D The disposition transaction represents shares withheld by the Issuer in connection with the vesting of certain restricted stock units under the restricted stock units award agreement entered into as of December 7, 2015 between the Issuer and the Reporting Person pursuant to the Issuer's Amended and Restated Stock Incentive Plan. The reported shares were withheld to satisfy the Reporting Person's tax withholding obligations. The Issuer will pay these taxes on behalf of the Reporting Person. Mark N. Rogers, Attorney-in-Fact 2018-12-11