Arena Raises $200M Series B at $3.1B Valuation

Arena, a company focused on real-world AI evaluation and alignment, has raised $200 million in a Series B funding round. This latest investment brings the company's valuation to $3.1 billion and follows significant growth in their platform for evaluating AI agentic capabilities.

Investors

The funding round was co-led by Lightspeed Venture Partners and Khosla Ventures. Participating investors include Salesforce Ventures, 01 Advisors, Dell Technologies Capital, and Endeavor Catalyst, with continued support from existing backers including a16z, Felicis, AMP PBC, QuantumLight, and The House Fund.

Arena Use of Funds

Arena plans to use the new capital to continue its mission to measure and advance the AI frontier for real-world use, specifically by expanding its evaluation capabilities and further developing its newly introduced Alignment Index.

About Arena

Founded as a research experiment, Arena provides an independent, data-driven platform that measures the capability, safety, and alignment of frontier AI models. Through its Agent Arena platform and new Alignment Index, the company monitors how AI agents perform tasks such as coding, document analysis, and creative writing in real-world human workflows to ensure they act in line with human intent.

Funding Details

Company Website: https://arena.ai

Company: Arena
Raised: $200M
Round: Series B
Funding Date: October 2026
Lead Investor: Lightspeed Venture Partners, Khosla Ventures
Additional Investors: Salesforce Ventures, 01 Advisors, Dell Technologies Capital, Endeavor Catalyst, a16z, Felicis, AMP PBC, QuantumLight, The House Fund
Company Website: https://arena.ai
Software Category: AI Evaluation and Alignment
Source: https://arena.ai/blog/series-b