HiddenLayer Raises $100 Million to Strengthen AI Agent Security

American cybersecurity company HiddenLayer has just closed a $100 million Series B funding round, entirely dedicated to strengthening AI agent security in production. Announced on September 3, 2026, this raise brings the total amount collected by the Austin-based startup since its founding in 2022 to more than $155 million, and illustrates the urgency felt by companies as autonomous agents gain more autonomy within their information systems.

A Startup Born to Protect AI Systems

Founded in 2022, HiddenLayer first made a name for itself by protecting machine learning models against theft, manipulation, or poisoning of training data. With this new funding round, the company is expanding its scope to AI agent runtime security: real-time monitoring of actions performed by an agent in production, detection of abnormal behavior, and blocking of unauthorized actions before they cause harm. This is an especially sensitive effort given that some agents now write, test, and deploy code with reduced human oversight, a use case that several experts already recommended monitoring through a security feature worth checking before launching any AI agent project.

A Funding Round That Reassures Enterprise Customers

The funding round is led by Delta-v Capital, with participation from Booz Allen Ventures, Microsoft's M12 fund, Morgan Stanley, and Ten Eleven Ventures. The presence of these players, accustomed to the strict due diligence of the defense and finance sectors, is seen as a strong signal by IT leaders who are still hesitant to open their production environments to autonomous agents. Co-founder and CEO Chris Sestito claims an approach to trust built, in his words, well before most of the market perceived the urgency.

Risks Already Documented by Several Industry Players

This funding round comes as warnings about the possible missteps of autonomous agents multiply. A coalition of more than a hundred technology companies, for example, set up a traceability system this summer designed to identify AI agent mishaps observed in real-world environments, while a major American software company chose to voluntarily slow the rollout of its most powerful agent models after discovering critical security flaws. The issue also affects budgets: another startup had already raised several tens of millions of dollars this spring to help companies better govern the costs of their AI agents in production. In this climate of heightened vigilance, some scammers are even taking advantage of the hype to offer fake tools, which has prompted several experts to publish guides on spotting scams posing as autonomous agents.

What the Funding Will Actually Finance

According to information provided by the company, the funds will primarily be used to develop three components: automatic discovery of AI applications deployed within the information system, securing the supply chain of models used by agents, and attack simulation capabilities to test agents' resilience before they go into production. HiddenLayer is specifically targeting AI coding agents, increasingly used to write and review code in a nearly autonomous way, a use case identified as one of the most exposed to manipulation risks.

Frequently Asked Questions

How much has HiddenLayer raised in total since its founding?

With this additional $100 million raised in Series B, HiddenLayer has collected more than $155 million since its founding in 2022.

Who participated in this funding round?

The funding round was led by Delta-v Capital, with participation from Booz Allen Ventures, Microsoft's M12 fund, Morgan Stanley, and Ten Eleven Ventures.

What does AI agent runtime security cover?

It involves continuously monitoring the actions performed by an AI agent once deployed in production, in order to detect any abnormal behavior, manipulation, or unauthorized action before it causes real harm.

Sources

SecurityWeek,
Yahoo Finance,
PR Newswire

This article was written with the help of artificial intelligence. Editorial policy