#1 On July 14, 2021 the Leadership and Compensation Committee certified that certain performance metrics under previously granted performance stock units were satisfied. These performance stock units were previously granted in February 2019 under the 2017 Stock Incentive Plan.

#2 On July 14, 2021 the Leadership and Compensation Committee certified that certain performance metrics under previously granted performance stock units were satisfied. These performance stock units were previously granted in February 2020 under the 2017 Stock Incentive Plan.

#1 Award of Restricted Stock Units under the 2017 Incentive Plan. 25% vests on each anniversary of the grant date.

#1 Represents shares of Alexion common stock disposed in connection with the Agreement and Plan of Merger (the "Merger Agreement") dated as of December 12, 2020, by and among Alexion and AstraZeneca PLC. In accordance with the Merger Agreement, upon the First Effective Time (as defined in the Merger Agreement), each share of Alexion common stock was converted into the right to receive (i) 2.1423 American Depositary Shares (ADSs) of AstraZeneca PLC and (ii) $60.00 in cash (the "Merger Consideration").

#1 This sale was made to cover withholding taxes immediately following the vesting of previously granted Restricted Stock Units.