Tenex.ai raises $250M Series B to scale AI-native cybersecurity with human oversight

What's the deal? Sarasota, Florida-based AI cybersecurity startup Tenex.ai has raised $250 million in a Series B round at a valuation exceeding $1 billion.

The round was led by Crosspoint Capital PartnersDealroom has a profile for this one. Try Dealroom →, with participation from Shield CapitalDealroom has a profile for this one. Try Dealroom → and DeepWork CapitalDealroom has a profile for this one. Try Dealroom →. Tenex has previously raised capital from Andreessen Horowitz. The company also announced the appointment of Bashar AbouseidoDealroom has a profile for this one. Try Dealroom →, former chief information security officer at Charles SchwabDealroom has a profile for this one. Try Dealroom →, as president.

Founded and led by chief executive officer Eric FosterDealroom has a profile for this one. Try Dealroom →, Tenex sells an AI-native managed detection and response (MDR) service that combines automated threat-finding with human analyst oversight. Its platform processes 100% of customer alert telemetry in under a minute — compared to an industry average of roughly 10% reviewed by a typical security operations centre.

The company has partnerships with Google, Microsoft, and Amazon to deliver those companies' security products to enterprise clients. Tenex has been in market since early 2025, generating more than $25 million in contracted revenue to date.

Why now? Cyber attacks are accelerating in volume and sophistication as malicious actors increasingly use AI to automate their own offensive operations. Traditional security services models — where each new customer requires dedicated specialist headcount — are breaking under the strain. Tenex's pitch is that AI automation changes that equation: the same number of human analysts can cover far more ground, making the MDR model financially viable at scale.

The company plans to hire more than 250 people by end of 2026, growing from nearly 100 to 300 employees, and to expand into Europe, the Middle East, and Africa.

What could go wrong? The AI security space is crowded and moving fast. OpenAI recently agreed to acquire PromptfooDealroom has a profile for this one. Try Dealroom →, a company that helps enterprises find and fix security flaws in AI models, and both OpenAI and AnthropicDealroom has a profile for this one. Try Dealroom → have unveiled AI agents aimed at security teams. Larger incumbents — including the hyperscalers Tenex partners with — could absorb the MDR market by bundling security services into their platforms.

Tenex also faces a structural vulnerability: the more enterprises rely on a single managed service provider, the more attractive that provider becomes as a target.

The signal: AI is reshaping cybersecurity from both sides — attackers and defenders are deploying it at scale, and the advantage will go to whoever automates most effectively. Tenex's model, blending AI triage with human judgment rather than replacing analysts entirely, reflects a growing consensus that the future of enterprise security is not fully autonomous but augmented. The raise signals investor conviction that managed security services, long seen as a low-margin commodity, can be transformed into a high-margin, scalable business by AI.

Sources:
Tenex.ai
Business Journals
Business Observer
Bloomberg

Image credit:
Tenex.ai

J.V.