Arena raises $200M Series B at $3.1B valuation, launches Alignment Index
arena · x · 2026-10-13
Arena announced a $200M Series B at a $3.1B valuation and launched the Arena Alignment Index, celebrating at NYSE.
The index evaluates how safely and reliably AI behaves in practice, built from real-world agent traces, with three signals: Unauthorized Action, False Attribution, and Deceptive Completion.
Arena says independent evaluation matters more as AI agents grow more autonomous; the funding will go toward safety signals, agentic capabilities, and new modalities. The 90-person team is hiring across research, product, engineering, and design.
Related event: Arena Raises $200M Series B at $3.1B Valuation(2 posts)→
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