AI evaluation company Arena announced a $200 million Series B at a $3.1 billion valuation on October 8, 2026, in a round co-led by Lightspeed Venture Partners and Khosla Ventures, and released a preview of its Arena Alignment Index alongside the financing. Series B Investors and Stated Purpose Salesforce Ventures, 01 Advisors, Dell Technologies Capital and Endeavor Catalyst participated in the round, and existing investors a16z, Felicis, AMP PBC, QuantumLight and The House Fund also supported…