HiddenLayer raised $100 million in a Series B round led by Delta-v Capital. Ten Eleven Ventures, Morgan Stanley, Microsoft's M12 and Booz Allen Hamilton also took part. The Austin company sells tools that protect AI models, agents and workflows from attack. Chief executive Chris Sestito says annual recurring revenue grew more than tenfold in a year. He put the figure in the tens of millions and credited new customers for most of it. Banks and large technology firms are its biggest markets, alongside US defence and intelligence contracts. HiddenLayer extended its existing products to cover prompt injection, agent manipulation and malicious tool use. It scans about 50 AI file formats to check open-weight models are what they claim. The money will go mainly to sales and distribution, plus expansion into Europe. Sestito conceded that Microsoft, OpenAI and AWS could bundle some of this into their platforms.

• $100M Series B
• ARR grew more than 10x in a year
• $2.83B AI security spend in 2026
• 83% more than 2025