This is a monthly feature that runs down some of the most-active investors in U.S.-based companies, looks at some of their most interesting investments, and includes some odds and ends of who spent what. See April’s most-active startup investors here.

Similar to April, big-named investors dominated investing in U.S.-based startups last month.

Andreessen Horowitz, General Catalyst, Sequoia Capital, Khosla Ventures, Founders Fund and Alumni Ventures led the way in the number of deals, although only a16z hit double digits, with 10 investments.

Just a couple of years ago it was not uncommon for firms to need a dozen or more deals to head up this list. But as the venture market continues to plug along, a smaller amount of deal-making seems to be the preferred route for even the biggest VC firms.

Andreessen Horowitz, 10 deals

May’s total was the most deals for a16z since January — when it took part in 15 financings.

Of course, the biggest deal it took part in was the $6 billion round for xAI, Elon Musk’s generative AI startup. The round, which also included participation from Sequoia, Valor Equity Partners and Fidelity Management & Research Co., values the startup at $24 billion post-money — making it the second-most-valuable VC-backed generative AI company in the world behind only competitor OpenAI.

However, that was not the only big deal a16z completed last month. The firm also co-led cloud security startup Wiz’s massive $1 billion raise at a $12 billion valuation. The round, which also counted Lightspeed Venture Partners and Thrive Capital as co-lead investors, is the biggest cybersecurity round of the year thus far.

In addition, the firm led smaller rounds for AI cancer treatment startup Valar Labs, weapon targeting company ZeroMark, and Rollup, a collaborative platform for hardware.

General Catalyst, 8 deals

General Catalyst led the way in April, but dropped down a few deals in May.

Nevertheless, it did take part in a couple of pretty big rounds. The New York investment firm participated in Karius’ $100 million Series C. The startup helps give genomic insights into infectious diseases.

General Catalyst also co-led — along with 7wire Ventures — San Francisco-based personalized healthcare platform Transcarent’s $126 million Series D that valued the company at $2.2 billion.

Sequoia Capital, Khosla Ventures, Founders Fund and Alumni Ventures, 7 deals each

A quartet of well-known firms each deadlocked at seven deals. Sequoia, Khosla and Founders Fund all made fewer investments in May than they did the previous month, whereas Alumni’s number of deals jumped from April but was still its second-lowest deals amount since at least the beginning of 2023.

Similar to a16z, Sequoia Capital also took part in both xAI’s and Wiz’s huge rounds. It also led a $26.5 million Series B for quantum computing startup Quantum Circuits.

Khosla actually co-led Karius’ previously mentioned $100 million round, as well as Rad AI’s $50 million Series B. The San Francisco-based startup develops software that uses AI to automate radiology report writing.

The largest round Founders Fund participated in was Scale AI’s huge $1 billion round led by Accel that values the data labeling and evaluation startup at a stunning $13.8 billion. However, it also led a $45 million Series B for New York-based Polymarket, a prediction market platform where traders predict future outcomes based on news in real time.

Alumni usually invests in smaller earlier-stage rounds, and that was the model it followed in May with everything being pre-seed to Series A. The only exception was participating in Frore Systems’ big $80 million Series C led by Fidelity Management & Research Co. The San Jose, California-based startup has developed a solid-state active cooling chip — AirJet — that allows users to leverage AI even on the edge of networks or on edge devices without them getting too hot and losing performance.

Also notable:

• Accel came in next on the list with six deals.
• Khosla Ventures and Accel led the way in most led or co-led deals in May with four.
• Accel also led the list for number of rounds led or co-led with the highest dollar amounts, leading or co-leading four rounds that in total were worth almost $1.3 billion.
• Y Combinator once again was the top investing incubator and accelerator with 10 deals in May.

Methodology

This is a list of investors which took part in the most rounds involving U.S.-based startups. It does not include incubators or accelerators due to the fluctuations their investment numbers can have.

Illustration: Dom Guzman