August was another big month for startup funding, and the most active investor rankings were once again dominated by familiar names. Always-busy Y Combinator was the most active backer of U.S.-based startups by deal count, while General Catalyst led or co-led the most rounds of $5 million or more, Crunchbase data shows. Chip giant Nvidia, meanwhile, sharply accelerated its dealmaking, ranking among the most active and highest-spending investors for the month. The chip giant participated in nine disclosed rounds of at least $5 million — marking its busiest month for investing since at least the beginning of 2025 — and led or co-led financings collectively valued at $1.3 billion.

The flurry of activity came as global venture funding reached $42 billion in August, up 122% year over year, with seven companies raising billion-dollar-plus rounds last month. Below, we rank August’s most active startup investors across several categories, including lead backers, prolific venture dealmakers, highest spenders and seed investors.

Active lead investors San Francisco-based General Catalyst ranked as the most active lead investor in rounds of $5 million or more, leading or co-leading five such deals. Its largest was the $1.1 billion Series A for River AI, which provides custom AI fine-tuning for businesses. General Catalyst also led or co-led a $116 million Series E for Cityblock Health, along with three seed rounds ranging from $10 million to $25 million, Crunchbase data shows. Andreessen Horowitz, Sequoia Capital and S3 Ventures tied for second, with four lead or co-lead deals each.

When we widen the ranking to include both lead and non-lead participation in rounds of $5 million or more, Y Combinator once again takes the top spot. The accelerator participated in at least 18 such deals in August, per Crunchbase data. Andreessen Horowitz ranked second with 13 deals, followed by General Catalyst with 10. Alumni Ventures and Nvidia tied for fourth with nine each. Nvidia’s rise in the investor rankings is particularly notable. The Santa Clara, California-based chip giant participated in only four U.S. rounds of $5 million or more in July and one in August 2025. Seven of its nine qualifying investments last month went to companies categorized as AI-focused in Crunchbase, including River AI, Poolside, Groq, Starcloud and Generalist AI.