By Rachel Metz | Updated on Oct 08, 2026 at 05:00 PM
Arena Intelligence Inc., the startup behind a popular artificial intelligence model leaderboard, has raised $200 million in funding at a $3.1 billion valuation and plans to expand into measuring AI safety, tapping into growing demand to evaluate the technology’s performance and risks.
The financing, set to be announced Thursday, was led by Lightspeed Venture Partners and Khosla Ventures, with participation from Salesforce Ventures and Dell Technologies Capital. The startup was previously valued at $1.7 billion in a funding round in January.
Arena began in 2023 as Chatbot Arena, a research project from the University of California at Berkeley’s
Sky Computing Lab
that allowed anyone to try state-of-the-art AI models and rank the responses. Introduced a few months after OpenAI’s release of ChatGPT kicked off an AI frenzy, Chatbot Arena soon became a popular spot for the industry’s early adopters, and a leading indicator in the rapidly evolving field of AI benchmarking.
The academic project
transformed into a company
in 2025 and has since branched out to include a number of different leaderboards that let people measure AI models on a
slew of different tasks. Arena now gets tens of millions of visitors per month, according to Anastasios Angelopoulos, the company’s co-founder and chief executive officer.
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Arena plans to roll out a new leaderboard on Thursday showing how AI models stack up on several measures of alignment, a term often used to refer to how well the software follows the objectives people set for it. The company’s Alignment Index will track how effectively and safely AI models can work with people on activities like coding, Angelopoulos said, by considering signals such as how often a model takes an unauthorized action or tells a user it finished a task that it didn’t actually complete.
Leading AI model makers such as OpenAI and Anthropic PBC are currently grappling with rising concerns about their most advanced artificial intelligence products after a spate of
recent hacking incidents
involving rogue AI systems. The security breaches, and
escalating warnings of existential risks
within the industry, have sparked calls for greater safeguards and oversight of the technology.
Initially, Arena’s alignment index includes more than two dozen different AI models, with OpenAI’s GPT-6.1 Sol and Anthropic’s Claude Opus 5.5 in first and second place, respectively.
Arena is pulling the alignment data from conversations users have with AI models through its Agent Arena, a platform that lets people use models for more complicated multistep tasks. Angelopoulos said Arena plans to expand the leaderboard to include more safety-related signals over time.
With the latest round of funding, Angelopoulos said Arena also plans to its expand its evaluation work to a broader range of businesses, helping them use their own data to determine which AI models make sense for them to run.
“We’re in the early days of it now,” Angelopoulos said. “We’ve made good progress.”