Sierra raises $950M Series E

Sierra helps businesses to build and deploy AI agents that communicate with users across channels such as chat, voice, email, and messaging. The company announced a $950M Series E on May 4, 2026, from its base in San Francisco, US. Investors and valuation were not disclosed in Crunchbase's round record; Lounge adds them as they are reported. It has raised more than $100M in total venture funding.