HiddenLayer, an Austin, Texas-based AI security startup, has raised $100 million in a Series B round, the company announced this week. Delta-v Capital led the round, joined by Ten Eleven Ventures, Morgan Stanley, Microsoft’s venture arm M12, and Booz Allen Ventures.
The company protects generative, agentic, and predictive AI systems throughout their lifecycle — spotting vulnerabilities before deployment and blocking attacks at runtime. With the new funding, HiddenLayer plans to expand Agent Harness Security, a product built to guard AI coding agents — autonomous tools that write and execute code — while they operate inside a company’s systems.
Rapid growth
HiddenLayer said its annual recurring revenue grew more than tenfold over the past year, with more than 90% of that growth coming from new customers. The company signed more than 50 new platform customers over the period, across sectors including financial services, pharmaceuticals, defense, and intelligence agencies. It also said it supports an unnamed “leading frontier model provider” whose product serves more than 700 million weekly users, though it did not identify the client.
CEO Chris Sestito said the funding would let the company keep growing “the purpose-built team and platform required” as agentic AI becomes core to enterprise operations.
Patents and positioning
HiddenLayer holds 39 granted patents and 65 more pending, covering adversarial-detection and model-protection technology, the company said. Counting an earlier $6 million seed round, the new raise brings HiddenLayer’s total funding to around $156 million, according to TechCrunch — one of the largest rounds yet for a company focused solely on AI security.
Growing scrutiny
The round adds to a wave of investment in AI security this year, as companies hand more day-to-day work — writing code, managing infrastructure, executing trades — to autonomous AI agents rather than only chat interfaces. The raise follows Anthropic’s own push to fund AI-security research, including a $35 million Defender Fund launched earlier this year, and comes as major labs like Google ship cybersecurity-focused model variants alongside their flagship releases. HiddenLayer is one of a growing number of startups building security tools purpose-built for AI systems, rather than adapting traditional software-security products.