Proofpoint acquires rival Hornetsecurity for over $1 billion to boost European expansion ahead of IPO

Cybersecurity firm Proofpoint is acquiring German cybersecurity firm Hornetsecurity for over $1 billion, marking its largest deal to date as it looks to expand in Europe and prepare for a return to the public markets.

The move helps Proofpoint cement its European presence and gives it a stronger foothold in the managed service provider (MSP) market. It also sets the stage for a return to the public markets, a plan the company has been quietly lining up since going private in 2021.

Proofpoint, owned by private equity giant Thoma Bravo, confirmed the acquisition on Thursday. The company told CNBC that the deal strengthens its offerings for small and medium-sized businesses, particularly those relying on MSPs for cloud-based email protection, data loss prevention, and Microsoft 365 security.

The acquisition would help “consolidate fragmented security tools into a unified platform that protects people and defends data across the global threat landscape,” Proofpoint CEO Sumit Dhawan told CNBC.

Cybersecurity consolidation is picking up pace as companies scramble to keep up with AI-fueled threats. Proofpoint’s deal is the latest in a string of high-profile acquisitions. In March, Google agreed to buy cloud security startup Wiz for $32 billion, and just last month, Palo Alto Networks announced plans to acquire AI-focused Protect AI.

Headquartered in Hannover, Hornetsecurity has carved out a strong position in the European market, serving more than 125,000 SMBs with a team of over 700 employees. The company focuses heavily on email security and compliance, which have become top concerns for businesses caught in the crosshairs of AI-driven attacks.

“Generative AI has fundamentally changed the threat landscape, enabling faster, more targeted, and more complex attacks,” Dhawan said in an interview with CNBC. He added that small and mid-sized firms “are increasingly in the crosshairs” and need “integrated, high-efficacy” security platforms.

Dhawan described the acquisition as a way to simplify and unify fragmented security tools. “It helps us consolidate fragmented security tools into a unified platform that protects people and defends data across the global threat landscape,” he said.

This isn’t just a move to beef up product offerings. Proofpoint has its eyes on going public again. The company’s leadership said last year they were weighing external funding and acquisitions as part of a broader strategy to return to the stock market by 2026. This Hornetsecurity deal is clearly a step in that direction.

“Hornetsecurity brings very strong business to Proofpoint, targeting a new market segment of MSPs and diversifies our routes to market,” Dhawan said. “It contributes significantly to our earnings and cash flow going forward, which makes us an even stronger company and business as we explore a return to public markets.”

Proofpoint itself employs over 4,500 people and counts 85% of the Fortune 100 as customers. The Hornetsecurity deal is expected to close in the second half of 2025, pending the usual closing conditions.

The acquisition also highlights a broader trend in cybersecurity: consolidation. Larger firms are buying up smaller players to stay competitive in an industry where AI has supercharged both innovation and threats. Just this year, Google said it would acquire cloud security startup Wiz for $32 billion, and Palo Alto Networks announced plans to buy Protect AI, an AI-focused security startup.

For Proofpoint, this deal isn’t just about scale. It’s about staying relevant—and ready—for what comes next.

Private equity giant Thoma Bravo acquired ProofPoint in April 2021 for $12.3 billion.