---
title: "Bessemer Leads Onyx Security $113M Series B for the Agentic Control Plane"
description: "Bessemer Venture Partners led Onyx Security’s $113M Series B (~$640M valuation) in July 2026 to build a secure control plane for enterprise AI agents — steering risky actions instead of only blocking them."
date: 2026-07-29T00:00:00.000Z
tags: ["bessemer-venture-partners", "series-b", "cybersecurity", "artificial-intelligence", "startup-funding", "2026-vc-news", "venture-capital"]
source: https://venturecapitaltracker.com/2026-bessemer-onyx-security-113m-series-b
---

# Bessemer Leads Onyx Security $113M Series B for the Agentic Control Plane

> Bessemer Venture Partners led Onyx Security’s $113M Series B (~$640M valuation) in July 2026 to build a secure control plane for enterprise AI agents — steering risky actions instead of only blocking them.

**Bessemer Venture Partners** led **Onyx Security’s $113 million Series B** (July 29, 2026) at an estimated **~$640 million** valuation — betting that the generational security company of the agent era will look like a **control plane**, not another alert feed.

## Key facts

- **Lead:** [Bessemer Venture Partners](/fund/bessemer-venture-partners)
- **Company:** Onyx Security (secure AI control plane)
- **Round:** $113M Series B
- **Valuation:** ~$640M (press reports)
- **Date:** July 29, 2026
- **Other investors:** Cyberstarts, TCV, Conviction, FirstMark, Vintage Investment Partners, QuantumLight, G Squared
- **Total funding (reported):** ~$153M after prior seed + $35M Series A / stealth capital
- **Founders:** Maxim Bar Kogan (CEO), Gil Elbaz (Chief AI Officer)

## Who uses Onyx — and why

Buyers are **CISOs, SecOps, and platform engineering** teams rolling out agents that can call APIs, move data, spend money, and ship code.

They use Onyx to answer:

1. Which agents exist across SaaS, cloud, endpoints, and internal infra?
2. What is each agent allowed to do?
3. Can we stop or **steer** a dangerous action in flight without killing productivity?

Bessemer’s note: sophisticated buyers who already evaluated well-funded peers still chose Onyx for broader visibility, fewer false positives, and steering over blunt blocking — including Fortune 500 design wins for a young company.

## Why this is a live problem now

Agents are nondeterministic, high-privilege actors. Static rules cannot enumerate every path. Identity lockdown alone defeats the usefulness of agents. Human approval at machine volume does not scale. Bessemer’s framing: every platform shift minted a category leader (network → Palo Alto, endpoint → CrowdStrike, cloud → Wiz); agents are next, and faster.

## Why raise from Bessemer (portfolio fit)

| Bessemer asset | Why it helps Onyx |
| --- | --- |
| Cyber roadmap since the 1990s | Instant category credibility with enterprise buyers |
| Cloud Index / enterprise brand | Series B is about GTM as much as product |
| Agentic stack thesis | BVP says it backed the agent era from the model layer up; Onyx is “how that world gets secured” |
| Check + syndication | $113M with TCV etc. is a board-building growth round |

Likely founder reason to take BVP’s term sheet: you are selling to the same IC and CISO networks Bessemer has served for decades — and you want a lead that will not treat agent security as a side experiment.

## Competitive map

- Incumbent EDR / SSE / cloud security suites retrofitting agent plugins.
- API-only / agentless visibility tools (observe after the fact).
- Peer agent-security startups competing on runtime enforcement (including Neo — different wedge: endpoint sensor vs control-plane mesh).

## Practical takeaway

- **Founders:** “Block everything dangerous” loses to **steer and continue** in agent markets. Product demos should show a redirected safe path, not only a deny.
- **Investors:** Underwrite false-positive rate and inline latency. Bessemer’s diligence language centers model-small-enough-to-sit-on-traffic plus Guardian escalation.

## Sources

1. Onyx — $113M Series B blog (Jul 29, 2026): https://www.onyx.security/blog/onyx-113m-series-b-keeping-humans-in-control-as-ai-becomes-smarter
2. Bessemer — Onyx investment note: https://www.bvp.com/news/onyx-security-defining-cybersecurity-in-the-agentic-era
3. Bessemer fund profile: [/fund/bessemer-venture-partners](/fund/bessemer-venture-partners)