HiddenLayer raised $100M for runtime AI security after 10x ARR growth.

Announced September 2, the Series B was led by Delta-v Capital with Ten Eleven, Morgan Stanley, M12 and Booz Allen participating, bringing total funding to roughly $156M. The company says ARR grew more than 10x in the past year and it signed more than 50 new platform customers. Its argument is that AI cannot be made trustworthy through design-time principles alone, so protection has to run at inference time, and it's now competing to monitor tools and add-ons rather than only agents.