AI security startup HiddenLayer has raised $100M in a Series B led by Delta-v Capital, betting that enterprises will spend heavily to protect models and agents from attack. Ten Eleven Ventures, Morgan Stanley, Microsoft’s M12 and Booz Allen Ventures also joined the round.
The Austin-based company, founded in 2022, checks models and their software packages for tampering before deployment, runs red-team exercises against them and watches live systems at the inference layer for prompt injection and model theft. CEO and co-founder Chris Sestito said annual recurring revenue grew more than tenfold over the past year to the tens of millions of dollars, with over 90% of that growth coming from new customers.
Financial services and large tech firms building AI products are its biggest verticals, and one customer is a frontier model provider with more than 700 million weekly users, which the company did not name. HiddenLayer also holds contracts with the Department of Defense and the intelligence community.
The new money will expand Agentic Runtime Security, its line for watching agents in production, and Agent Harness Security, aimed at autonomous coding agents. Counting a $6M seed and a $50M Series A from 2023, HiddenLayer has now raised about $156M.
The round lands as Gartner projects $2.83B in AI-security spending this year, up 83% from 2025. Three years after investors wondered whether AI threats would materialize at scale, the market for stopping rogue agents and poisoned models has arrived.
