We invest only in Silicon Valley's top AI companies.
Lambert Fund makes a small number of large, long-term investments in the companies building the foundations of the AI era — the frontier labs, the infrastructure beneath them, and the machines they will run.
About the firm →A small fund with a narrow mandate.
Lambert Fund was founded in 2026 in Palo Alto by Ramble, an investor who has backed Silicon Valley's frontier AI companies across successive rounds — and who continues to invest his own capital in every position the fund takes.
The fund exists to do one thing: own meaningful stakes in the few AI companies that will still matter in ten years, and hold them. We do not run a broad portfolio. We do not chase themes. We do not invest outside Silicon Valley.
Few companies. Large positions. Long holds.
Concentration over coverage.
A handful of companies rather than a hundred. We would rather own more of the right company than a little of everything, and we size positions accordingly.
The leader, not the alternative.
In every category we back the company that is already ahead. We do not fund the second-best at a discount, and we do not invest outside Silicon Valley, whatever the price.
Bought to hold.
We follow our companies round after round and hold through the IPO and beyond. Our time horizon is the company's, not the fund cycle's.
Access, not just capital.
The best companies rarely raise in public. We reach them through direct allocations, long relationships with the venture firms that lead their rounds, and secondary purchases from early shareholders.
Three layers of the AI economy.
The modelsFrontier labs
The laboratories building the most capable models in the world and becoming the default interface between people, organizations and intelligence. The core of the portfolio.
The substrateAI infrastructure
The compute, cloud and systems companies that every lab depends on and every application pays for — the layer that gets paid whoever wins the model race.
The machinesPhysical AI & deep tech
Humanoid robotics, launch, and the frontier of hard science. Where a category leader is still emerging, we take an early position and follow the winner.
Selected investments.
Companies backed by our General Partner personally and through affiliated vehicles, ahead of the fund.
San Francisco
San Francisco
Public company
Early investor
Silicon Valley
A representative selection, not a complete list. Company names are used for identification only. Past investments are not indicative of future results.
How we think.
Our General Partner's view of the AI economy is published in The Cognitive Machine (2026): why value in this cycle accrues to a very small number of companies, why the application layer is structurally fragile, and why Silicon Valley sees the future before anyone else does. The questions the book asks of the industry are the questions we ask of every company before we invest.
“Don't ask whether AI is a bubble. Ask whether you are.”
The Cognitive Machine, 2026We convene the people we invest in.
For four consecutive years our team has hosted AGI Summit — formerly GenAI Summit — in the Bay Area, one or two editions a year, with more than 10,000 attendees and speakers from OpenAI, Google DeepMind, NVIDIA and Microsoft. It is where we meet founders and researchers long before a round is announced.
Work with us.
Founders
If you are building the leader in your category in Silicon Valley, we would like to know you early — before you raise.
Investors
Lambert Fund works with a small group of families and institutions. Qualified investors may request information.
Palo Alto, California