Proofpoint To Be Acquired By Thoma Bravo For $12.3B This is the biggest cybersecurity deal of all time, beating Broadcom’s $10.7 billion purchase of Symantec’s enterprise business, Intel’s $7.6 billion purchase of McAfee and Okta’s $6.5 billion purchase of Auth0. By Michael Novinson April 26, 2021, 09:47 AM EDT Private equity giant Thoma Bravo has agreed to purchase email security powerhouse Proofpoint for $12.3 billion in the biggest cybersecurity acquisition of all time. The Sunnyvale, Calif.-based company said the proposed acquisition will give Proofpoint the flexibility and resources needed to continue providing an effective cybersecurity and compliance offering. Proofpoint also expects to benefit from San Francisco-based Thoma Bravo’s operating capabilities, capital support and deep sector experience. The deal is expected to close in the third quarter of 2021.