U.S. startup investors concentrated capital into fewer deals in May, writing enormous checks for select companies. General Catalyst and Andreessen Horowitz led the charge as the most active investors, each co-leading six rounds. This pattern reflects a broader trend of capital flowing into fewer high-value deals, particularly within the artificial intelligence sector where consensus picks dominate funding rounds.

The month's standout deals included Anthropic's $50 billion Series H and Anduril's $5 billion funding round. Sequoia Capital, Altimeter Capital, Dragoneer, and Greenoaks co-led the massive Anthropic investment, while Thrive Capital and Andreessen Horowitz backed Anduril. Lightspeed Venture Partners followed with five lead deals, followed by Upfront Ventures and Index Ventures with four rounds each.

Familiar names consistently dominated the most active investor rankings, with Y Combinator, Andreessen Horowitz, and General Catalyst appearing across multiple categories. The funding landscape reflects recent large fund raises by established venture and growth investors. This concentration of capital into fewer deals suggests a strategic shift toward backing proven technologies and markets rather than spreading investments across numerous startups, particularly in high-growth sectors like artificial intelligence.