AI cloud security firm Upwind has raised $400 million in a funding round led by Bessemer Venture Partners, reaching a valuation of $3.8 billion. Existing investors Greylock Partners and Craft Ventures also participated in the financing. Upwind provides security protection for enterprise cloud infrastructure, focusing on detecting malware and suspicious activity. The company expanded its platform this year to address AI-related security risks. The new capital will be allocated toward engineering R&D and building out sales and marketing teams.