Robert Darren Lee - 31 Aug 2021 Form 4 Insider Report for PROOFPOINT INC

Footnote F1

On April 25, 2021, Proofpoint, Inc. (the "Company") entered into an Agreement and Plan of Merger (as it may be amended, supplemented or otherwise modified from time to time, the "Merger Agreement") with Project Kafka Parent, LLC ("Parent") and Project Kafka Merger Sub, Inc., a wholly-owned subsidiary of Parent ("Merger Sub"), pursuant to which Merger Sub was merged with and into the Company (the "Merger"), with the Company surviving the Merger as a wholly owned subsidiary of Parent. Pursuant to the Merger Agreement, all shares of Company common stock outstanding immediately prior to the effective time of the Merger (the "Effective Time"), were canceled and converted automatically into the right to receive $176.00 in cash.

Footnote F2

Each restricted stock unit represents a contingent right to receive 1 share of the Issuer's common stock upon settlement for no consideration.

Footnote F3

Pursuant to the Merger Agreement, immediately prior to the Effective Time, each unvested and outstanding restricted stock unit (each, an "Unvested Company RSU") was cancelled and converted into the right to receive an amount in cash equal to the product obtained by multiplying (x) the total number of shares of the Company's common stock underlying such Unvested Company RSU, by (y) $176.00, in each case subject to the same vesting schedule, termination terms and other conditions as such Unvested Company RSU was subject to immediately prior to the Effective Time, subject to the holder's continued service with the Parent or its affiliates.

Footnote F4

Restricted stock units do not expire; they either vest or are canceled prior to vesting date.

Footnote F5

The restricted stock units were earned by the Reporting Person on April 20, 2021 as determined by the Issuer's Board of Directors.