The announcement was made the same day that Proofpoint announced its first-quarter results, reporting total revenue of US$287.8 million, a rise of 15% year-on-year. However, the company failed to make a profit, reporting a loss of US$45.3 million.
Thoma Bravo already owns British security company Sophos, which it purchased for about US$3.9 billion in March last year. Thoma Bravo is also set to buy data integration and date integrity vendor for US$2.4 billion.
It has stakes in security firm McAfee and identity and access management vendor SailPoint.
A statement from Proofpoint said the deal was for US$176 per share in cash, a premium of about 34% over the closing share price on 23 April. The transaction is expected to close in the third quarter of 2021.
“Today’s announcement is a testament to the strength of Proofpoint’s people-centric approach to cyber security and compliance and underscores our important role preventing, defending and responding to today’s threats,” said Proofpoint chief executive and chairman Gary Steele.
“We have made tremendous strides in expanding the sophistication and scale of our offerings, and in 2020 we generated more than US$1 billion in annual revenue – making Proofpoint the first SaaS-based cyber security and compliance company to reach that milestone.
"We believe that as a private company, we can be even more agile with greater flexibility to continue investing in innovation, building on our leadership position and staying ahead of threat actors.
"Thoma Bravo is an experienced software investor, providing capital and strategic support to technology organisations, and our partnership will accelerate Proofpoint’s growth and scale at an even faster pace."
Seth Boro, a managing partner at Thoma Bravo, said: “Proofpoint has achieved tremendous outcomes for customers around the world, and we’re excited to partner with this talented team at a moment when organisations need innovative solutions to navigate an increasingly treacherous cyber security environment.
“Proofpoint places people at the center of its compliance and security strategy and plays a vital role in helping enterprises protect their data.
"Thoma Bravo’s approach to value creation is rooted in partnering with the organisation in which we invest and looking for opportunities to both enhance their existing operations and build technology platforms that drive significant growth.
"Proofpoint’s opportunity as a privately held company is incredibly compelling, and we look forward to working closely with them to drive continued business growth and deliver world-class advanced threat protection to even more customers in even more ways.”