What are the most valuable AI trust, risk and security startups?

Top startups in the AI TRiSM market ranked by valuation

Here is the current ranking of the most valuable AI TRiSM startups. For each one you will also find our confidence level and the valuation basis we used.

If you want to go deeper into the AI TRiSM startup landscape, check our report covering the AI TRiSM market.

1. Total funding is a minimum: some rounds have no public amount.
2. Total funding: cranium's reported July 2026 round is not independently confirmed.
3. Total funding excludes a reported 2025 investment not yet confirmed as equity.

Is Arena clearly the most valuable AI TRiSM startup today?

Yes. Arena is clearly the most valuable AI TRiSM startup today, with a reported $3.1B valuation and a 2.6x gap over the midpoint of the company ranked second.

Arena raised a $200M Series B in October 2026 at that valuation, after a $150M Series A in January 2026 and a $100M seed round in May 2025. The company evaluates frontier models and AI agents for real-world alignment, and AI labs and big companies want that kind of proof before they trust a system with important work. Arena also released a preview of its Alignment Index with the round, so the product now tracks models over time instead of testing them once.

The next group is much tighter. Zenity is valued at $833M–$1.6B, HiddenLayer at $667M–$1.2B and Braintrust at $800M. Arena is the only startup whose full valuation is safely above $1B, so for now there is a clear leader rather than a pack of co-leaders.

Are there many AI TRiSM unicorns yet?

No. The AI TRiSM market has only 1 startup whose entire valuation range is certainly $1B or more.

Zenity reaches $1.6B at the top of its range and HiddenLayer reaches $1.2B, but neither has a full range above $1B. Arena is the only company that clears the threshold without qualification. Counting the middle of each range, 2 companies fall in the $1B to $5B bracket, while 174 are below $1B.

That still looks like an early private market rather than a mature software category packed with unicorns. Many of the highest-ranked companies were founded in 2023, 2024 or 2025 and are still at Series A or Series B. Investors are already willing to pay for the possibility that AI security and evaluation become mandatory infrastructure, but most companies have not had enough time to prove that thesis at scale.

Is Zenity the closest challenger to Arena?

Yes. Zenity is the closest challenger to Arena in AI TRiSM valuation, with an implied valuation of $833M–$1.6B.

Zenity raised a $125M Series C in August 2026 led by Norwest, with participation from SoftBank Vision Fund 2, Hitachi Ventures and LG Technology Ventures. The company is built specifically around AI agent security, including systems that can decide and act across enterprise workflows. That gives Zenity a clear place in one of the hottest parts of the market right now: controlling what autonomous agents are allowed to access and do.

Arena is still in another tier. Arena's valuation is 2.6x the midpoint of Zenity's range. Zenity therefore looks like the strongest challenger rather than a co-leader, and its price shows how much investors are willing to pay for agent identity, permissions, monitoring and policy enforcement before the category has fully settled.

How valuable is HiddenLayer now?

HiddenLayer is one of the most valuable AI TRiSM startups today, third in the market with an implied valuation of $667M–$1.2B.

Its September 2026 $100M Series B was led by Delta-v Capital, with participation from Ten Eleven Ventures, Morgan Stanley, M12 and Booz Allen Ventures. HiddenLayer said the capital would deepen its enterprise platform, including runtime protection for agents and security for AI coding agents. The product already stretches across generative, predictive and agentic AI rather than one narrow control.

Braintrust is at $800M, Alice at $700M–$800M and Onyx Security at $640M, so HiddenLayer sits in a crowded second tier. Its full range does not yet make it a certain unicorn. The bet behind the price is straightforward: AI-specific attack surfaces become large enough to support dedicated security vendors instead of being absorbed entirely by existing cybersecurity suites.

Is Braintrust becoming more than an AI evaluation tool?

Yes. Braintrust's $800M announced valuation shows that AI evaluation and production monitoring are already being priced as core infrastructure.

Braintrust raised an $80M Series B in February 2026 led by ICONIQ, and the round valued the company at $800M. Braintrust describes itself as an observability layer for production AI, with evaluation built into how applications are developed, tested and monitored. That is a much bigger role than selling benchmark reports or occasional model audits.

Braintrust has raised $124M, compared with Alice at $240M and HiddenLayer at $156M. So investors are paying for the place Braintrust could hold in AI software, not for the money it has spent so far. If teams use one system to compare model versions, catch regressions and understand agent behavior, that system can become deeply embedded in production workflows.

Is Alice already a billion-dollar AI security company?

Not yet. Alice is reportedly valued at $700M–$800M, putting it among the largest AI TRiSM startups but still below the unicorn line.

Bloomberg reported in August 2026 that Alice raised $140M in a round led by Apax Digital. Israeli press reports put the valuation at $700M–$800M, fifth among AI TRiSM startups. The company focuses on protecting AI models from misuse and rogue behavior and has worked with major AI providers.

Alice has raised $240M, the second-highest total in our fundraising ranking, yet its $700M–$800M range sits right next to Braintrust's announced $800M, and Braintrust has raised $124M. That is a useful reminder that heavy funding does not automatically produce a higher valuation. Alice still has to turn a large capital base into enough commercial scale and differentiation to move clearly into the next tier.

Why is AI agent security startup Onyx Security valued so highly so quickly?

Onyx Security is reportedly valued at $640M because investors are paying for a fast-growing control layer around enterprise AI agents.

The company raised $113M in a July 2026 Series B led by Bessemer Venture Partners, bringing total funding to $153M. Onyx said revenue had grown fourfold in the four months since it emerged from stealth and pointed to Fortune 500 customers across banking, technology, insurance and energy. It also expanded integrations with Anthropic for runtime security around Claude.

That is a lot of progress for a company founded in 2024. Onyx is trying to become the place where enterprises discover agents, set policy, inspect behavior and intervene at runtime. Buyers appear willing to pay for that layer now rather than wait for large incumbent security vendors to add every control themselves.

Are AI agent security startups dominating the top valuations?

Largely yes. AI agent security startups occupy much of the top of the AI TRiSM valuation ranking today.

Zenity is valued at $833M–$1.6B, HiddenLayer at $667M–$1.2B, Onyx Security at $640M, Neo Security at $400M–$800M and WitnessAI at $387M–$725M. Straiker is also valued at $320M–$533M. These companies use different architectures, but they all protect autonomous AI systems rather than merely track application performance.

The recent rounds line up with those prices. Zenity raised $125M for enterprise agent security, HiddenLayer's $100M Series B emphasized agentic runtime protection, and Straiker's $64M Series A focused on discovery, adversarial testing and runtime defense. Autonomous agents create machine identities, permissions, tool access and action chains, so security teams suddenly have a new class of software actor to control.

WitnessAI belongs in that same top group. WitnessAI raised a $58M Series B in January 2026, with a focus on enterprise AI data flows and agent activity. Watching what AI does with company data, live, is clearly something buyers will pay for.

The table below shows the highest-valued AI TRiSM startups and their current valuation ranges.

Company	Valuation	Total raised
Arena	$3.1B	$450M
Zenity	$833M–$1.6B	$184M
HiddenLayer	$667M–$1.2B	$156M
Braintrust	$800M	$124M
Alice	$700M–$800M	$240M
Onyx Security	$640M	$153M
Neo Security	$400M–$800M	$100M+
WitnessAI	$387M–$725M	$86M
Patronus AI	$333M–$625M	$70M
Harmonic Security	$333M–$625M	$74M

Ranges are estimates or round-implied values as described in the methodology.

Is Patronus AI worth more because evaluation is moving into simulation?

Partly. Patronus AI is valued at $333M–$625M, and its push into large-scale simulation gives evaluation a much bigger job than static testing.

That valuation is our estimate from the size of its June 2026 Series B and is dated to that round; it was not announced by the company or investors. Patronus raised $50M in that Series B led by Greenfield Partners and introduced Digital World Models for simulating complex environments where AI agents can practice long-horizon tasks.

If agents need realistic environments before they are allowed into production, evaluation moves closer to core infrastructure. Patronus would then help decide whether an agent is ready to go live, before security tools even come into play. Its range remains below Braintrust's announced $800M, but investors are clearly funding more than one route to proving that advanced AI systems work well enough for real enterprise use.

Is Harmonic Security mainly a data-loss company or an AI security platform?

Harmonic Security now looks much more like an AI security platform for employee and agent use than a narrow data-loss product.

The company is valued at $333M–$625M and raised a $50M Series B in October 2026. Harmonic says its platform protects AI use for millions of employees at more than 100 companies and uses small language models to understand each AI interaction in context. Enterprises need to know which tools people use, what data moves through them and where agentic workflows create new risk.

Harmonic sits tenth in our valuation ranking, tied on displayed range with Patronus AI. Its challenge is obvious: incumbent data-security and browser-security vendors can add AI-specific controls. Harmonic therefore needs to stay useful across many AI applications rather than depend on one model provider or one narrow policy check.

Do higher AI TRiSM valuations always mean more capital raised?

No. AI TRiSM valuations and total funding often move very differently.

Braintrust is valued at $800M after raising $124M, while Alice has raised $240M but is reportedly valued at $700M–$800M. Onyx Security is reportedly valued at $640M on $153M raised. At the extremes of this comparison, Arena has the highest valuation-to-funding multiple at 6.9x, while Attestable has the lowest at 2.8x.

Different products need different amounts of capital. Evaluation software can scale differently from security businesses that build threat research, enterprise integrations and large sales teams. A heavily funded company can also stay at a lower valuation until investors see stronger commercial proof. Funding shows how much capital has gone in; valuation shows what investors think the company could become.

The table below shows examples of stated valuations compared with total equity raised.

Company	Valuation	Total raised	Multiple
Arena	$3.1B	$450M	6.9x
Zenity	$833M–$1.6B	$184M	6.5x
HiddenLayer	$667M–$1.2B	$156M	6.1x
Braintrust	$800M	$124M	6.4x
Alice	$700M–$800M	$240M	3.1x
Onyx Security	$640M	$153M	4.2x
Irregular	$450M	$80M	5.6x
Attestable	$80M–$133M	$38M	2.8x

Is the United States completely dominating AI TRiSM valuations?

The United States dominates AI TRiSM by company count, but Israel has a much stronger presence near the top than its size suggests.

Arena, HiddenLayer, Braintrust, Neo Security and WitnessAI are all American. Yet Zenity, Alice and Onyx Security, all from Israel, are in the top six, with Noma Security and AIR Security further down.

That fits Israel's long cybersecurity track record. Agent security, identity, runtime defense and data protection all look familiar to founders who have already built around earlier security shifts. The United States still has the biggest overall base because it combines frontier-model companies, enterprise software buyers and deep venture markets, but the top of AI TRiSM is clearly not American-only.

Is Europe producing serious AI TRiSM companies or mostly small governance vendors?

Europe is producing serious AI TRiSM companies, but its largest private valuations still sit below the US and Israeli leaders.

The United Kingdom leads Europe with Mindgard at $150M–$250M and Geordie AI at an announced $180M valuation. Geordie raised a $30M Series A in May 2026 and said ARR had grown 1300% in the first five months of the year. Mindgard raised a $30M Series A in August 2026 and said its technology had uncovered more than 150 publicly disclosed high-impact vulnerabilities across popular AI applications.

These are security and governance products aimed at enterprise agent deployment, red teaming and runtime control. Switzerland also has LatticeFlow AI and Modulos, while France has Naaia and Giskard. Europe has real technical depth; what it has not produced yet is an Arena-scale private valuation in this market.

Are acquisitions already validating AI TRiSM as a real software category?

Yes. Strategic buyers are already paying for AI TRiSM companies, which is strong evidence that these products are becoming part of the enterprise software stack.

Three AI TRiSM startups have already been bought at known prices: Arize AI at a $915M acquisition value, Lakera at $202M and Apex Security at $48M. Protect AI was acquired by Palo Alto Networks in July 2025 and integrated into Prisma AIRS. Palo Alto Networks said the acquisition would extend protection across models, applications and agents, including model scanning, posture management, red teaming and runtime security.

Fiddler AI gives another current example. CrowdStrike announced plans to acquire the company in November 2026, after Fiddler said in January 2026 that revenue had grown more than 4x over the prior 18 months; until the deal closes, our ranking still shows Fiddler as an independent startup valued at $200M–$375M. Large security platforms clearly want AI observability, evaluation and governance inside their own products rather than leaving every layer to independent startups.

Could AI certification startup AIUC become a much bigger company?

Possibly, but AIUC first needs outside AI trust checks to become a normal step before companies deploy AI, not a niche certification business.

AIUC is valued at $200M–$333M and raised a $40M Series A in September 2026, bringing total funding to $55M. The company positions itself around frontier AI standards and insurance and says companies including Cursor, ElevenLabs, Harvey, KPMG, Lovable, UiPath and Fin certify against its AIUC-1 trustmark. Its model is closer to an Underwriters Laboratories-style assurance layer than a conventional cybersecurity product.

That could become important if enterprises start requiring repeatable outside proof before deploying powerful AI systems. The obvious risk is fragmentation: standards can split across regulators, insurers and industry groups. For now, AIUC's valuation shows real interest in independent assurance, but it still sits well below the companies controlling runtime security and agent behavior.

So, which AI trust, risk and security startups are worth the most today?

Arena is the clear number one AI TRiSM startup by valuation today at $3.1B, followed by a second tier led by Zenity, HiddenLayer and Braintrust.

Zenity is valued at $833M–$1.6B, HiddenLayer at $667M–$1.2B, Braintrust at $800M, Alice at $700M–$800M and Onyx Security at $640M. The companies do different jobs, but most sit directly between powerful AI systems and real enterprise deployment.

That is where private-market value is clustering now. Evaluation, agent security, runtime control, data protection and enforceable governance all solve problems that appear once AI systems can actually act inside a company. AI TRiSM is already a meaningful software market, but one company is clearly a unicorn and the rest are still fighting over which control layers become durable platforms.

The table below shows the strongest conclusions from the article.

Question	Answer
Is there a clear valuation leader?	Yes, Arena sits well ahead of every other startup. Arena's reported valuation reaches $3.1B after its October 2026 Series B. No other startup has a full range close to it.
Is the AI TRiSM market full of unicorns?	Not at all, the unicorn club is still tiny. Only 1 startup has its whole valuation range above $1B. Many leaders are still young Series A or Series B companies.
Who is Arena's closest challenger?	Zenity, the Israeli agent security startup, comes closest. Zenity's August 2026 Series C implies a value of $833M–$1.6B. Arena is still worth 2.6x the midpoint of that range.
Are agents driving AI security valuations?	Yes, agent security fills much of the top ten. Zenity, HiddenLayer, Onyx Security and WitnessAI all protect AI agents. Companies now need controls over what AI agents actually do.
Can evaluation alone build a large company?	Yes, evaluation is turning into everyday production software. Braintrust carries an $800M valuation announced with its February 2026 Series B. Teams use it to test and monitor AI before and after launch.
Does more funding mean a higher valuation?	No, money raised and price often move apart. Alice raised $240M yet is reportedly valued at $700M–$800M. Braintrust reached an announced $800M with only $124M raised.
Is Israel important at the top?	Yes, Israel punches far above its weight here. Zenity, Alice and Onyx Security all sit in the top six. A long cybersecurity track record shows in agent security.
Why is Onyx Security priced so high already?	Investors are betting on very fast early growth. Onyx Security said revenue quadrupled in the four months after stealth. The July 2026 Series B came with a reported $640M valuation.
Are big security companies buying these startups?	Yes, strategic buyers are already paying for AI security. Palo Alto Networks completed its Protect AI acquisition in July 2025. CrowdStrike announced plans to acquire Fiddler AI in November 2026.
Can Europe compete in AI security startups?	Yes, but at smaller valuations than the leaders. Mindgard and Geordie AI show serious technical and commercial traction. Geordie AI said its ARR grew 1300% in early 2026.
What decides the winners now?	Being used in real production work matters most. Buyers pay for controls around AI systems that actually act. Demos and one-off audits count for much less than daily use.