AegisAI funding reaches $49 million after $36 million Series A

AegisAI funding has reached $49 million after the San Francisco email security startup said it raised a $36 million Series A to build defenses against AI-generated spear-phishing. Battery Ventures led the round, with Accel Partners and Foundation Capital, both existing investors, also participating.

The company did not disclose its valuation, revenue or headcount. The round comes less than a year after AegisAI’s public launch and follows a $13 million raise disclosed in September.

AegisAI sells email security built around its own large language models. Its argument is that phishing has shifted from clumsy, pattern-based lures to targeted messages that can mimic trusted colleagues or vendors using public web data and compromised accounts. The company says attackers can now produce these messages cheaply and at scale, which weakens security programs that rely heavily on employee recognition of suspicious writing or formatting.

What is AI spear-phishing?

AI spear-phishing is a targeted email attack in which generative AI helps research the victim, infer trusted relationships and write a message that appears to come from a familiar person or business contact. AegisAI says these attacks are harder for conventional filters to catch because the messages can be well written and may pass technical checks.

AegisAI’s product uses autonomous agents inside corporate inboxes to assess the sender, identity signals and the apparent purpose of each message. The company claims this approach can detect attacks that do not match known scam patterns and says it can reduce false positives by as much as 90% compared with legacy tools. That performance claim is AegisAI’s, and the company did not provide independent benchmark results in the announcement.

The startup’s own research is the main data point behind the timing of the raise. In a study AegisAI presented at the M3AAWG conference, based on more than 20,000 malicious emails, the company said AI-generated spear-phishing rose from 2.8% of observed phishing in early 2025 to 13.9% by year-end. It also said AI-written messages reached inboxes at nearly twice the rate of human-written phishing attempts. Among the AI-generated attacks that bypassed defenses, almost 73% had passed email authentication because they came from legitimate accounts attackers had taken over.

External loss data points in the same direction for buyer urgency. The FBI’s latest Internet Crime Report said reported victim losses hit $20.8 billion last year. Business email compromise accounted for $11.64 billion of that total, more than ransomware and malware combined, according to the FBI.

AegisAI was founded in 2025 by Cy Khormaee and Ryan Luo, both of whom previously worked in Google’s core security group on products including reCAPTCHA, Safe Browsing and Web Risk. Since launch, the company says it has signed dozens of fintech and technology customers, including Mesh Connect and LangChain. It also cited a case at Lokker in which its agents detected an attack sent through a vendor’s compromised Salesforce systems, without a malicious attachment or link.

The new capital is earmarked for expanding AegisAI’s set of defensive agents and for moving Vanguard, its threat-hunting agent, toward general availability. Vanguard, introduced in March, is designed to follow suspect links and attachments beyond the inbox and produce a threat report within minutes.

Battery Ventures general partner Dharmesh Thakker said generative AI has undermined assumptions behind older email security products and argued for defenses that operate at machine speed. That is the investment thesis AegisAI now has to prove in a crowded security market where many vendors are attaching AI agents to existing products.

This story draws on original reporting from SiliconANGLE.