Jonathan D. Feiber - 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

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 F3

Includes 1,397 Unvested Company RSUs.

Footnote F4

Held by the Feiber-Buhr Family Trust, of which the Reporting Person and his spouse are the sole trustees.

Footnote F5

Pursuant to the Merger Agreement, at the Effective Time, each vested Company stock option was cancelled and converted into the right to receive an amount in cash equal to (i) the difference between $176.00 and the exercise price of such stock option multiplied by (ii) the number of shares subject to such stock option.

Footnote F6

The stock option is fully vested.