Y Combinator CEO Garry Tan has said that for about a quarter of the current YC startups, 95% of the code was written by AI

Silicon Valley’s youngest startups are seeing a significant lift thanks to advances in artificial intelligence.

At this week’s annual demo day in San Francisco, Y Combinator — the startup accelerator behind companies like Airbnb, Dropbox, and Stripe — showcased its latest batch of early-stage companies to a room full of potential investors.

Y Combinator CEO Garry Tan told CNBC that this cohort is expanding faster than any in the accelerator’s history, with real revenue to show for it. According to Tan, the winter 2025 batch is growing at a pace of 10% per week across the board.

“It’s not just the top one or two startups — the entire group is growing 10% week over week,” said Tan, himself a Y Combinator alum. “That’s never happened before at this stage.”

Tan credits the surge to breakthroughs in AI. Developers are now able to automate repetitive work and generate new code using large language models. He referred to this trend as “vibe coding,” where AI models take the lead in writing software — in some cases, even building entire applications.

As AI takes on more of the development burden, many startups have been able to operate with smaller teams. Tan said that roughly a quarter of companies in the current YC batch wrote 95% of their code using AI.

“That might sound intimidating, but it means founders don’t need 50 or 100 engineers,” Tan said. “Startups can reach $10 million in revenue with fewer than 10 people. That reduces the need to raise large amounts of capital, and funds stretch much further.”

Tan noted that the previous “growth-at-all-costs” mentality common during the low-interest-rate era has given way to a renewed focus on profitability — a shift that’s also been seen at major tech firms like Google, Meta, and Amazon, which have gone through waves of layoffs and slowed hiring.

While this has created uncertainty for engineers, Tan sees opportunity.

“It’s easier than ever to build a startup,” he said, pointing out that today’s top engineers don’t have to prove themselves by joining a big tech company. “There’s a lot of anxiety among young software engineers, but maybe the one who couldn’t get hired at Meta or Google ends up building a business making $10 million or even $100 million a year with a small team — that’s a powerful shift.”

Around 80% of the companies that presented at demo day were focused on AI, with some in robotics and semiconductors. Tan said these startups are reaching commercial validation faster than previous generations.

tastytrade logo+
Get the best broker for options trading and earn Unusual Whales discounted! in cash with an eligible account deposit at tastytrade. Get an Unusual Whales bonus when you deposit $2000. Offer expires 3/31/25. Certain restrictions, terms and conditions apply.
Unusual Whales does not confirm the information's truthfulness or accuracy of the associated references, data, and cannot verify any of the information. Any content on this site or related pages are not intended to provide legal, tax, investment or insurance advice. Unusual Whales Inc. is not registered as a securities broker-dealer or an investment adviser with the U.S. Securities and Exchange Commission, the Financial Industry Regulatory Authority (“FINRA”) or any state securities regulatory authority. Nothing on Unusual Whales should be construed as an offer to sell, a solicitation of an offer to buy, or a recommendation for any security by Unusual Whales or any third party. Options, investing, trading is risky, and losses are more expected than profits. Please do own research before investing. Please only subscribe after reading our full terms and understanding options and the market, and the inherent risks of trading. It is highly recommended not to trade on this, or any, information from Unusual Whales. Markets are risky, and you will likely lose some or all of your capital. Please check our terms for full details.
Any content on this site or related pages are not intended to provide legal, tax, investment or insurance advice. Unusual Whales Inc. is not registered as a securities broker-dealer or an investment adviser with the U.S. Securities and Exchange Commission, the Financial Industry Regulatory Authority (“FINRA”) or any state securities regulatory authority. Nothing on Unusual Whales should be construed as an offer to sell, a solicitation of an offer to buy, or a recommendation for any security by Unusual Whales or any third party. Certain investment planning tools available on Unusual Whales may provide general investment education based on your input. You are solely responsible for determining whether any investment, investment strategy, security or related transaction is appropriate for you based on your personal investment objectives, financial circumstances and risk tolerance. You should consult your legal or tax professional regarding your specific situation. See terms for more information.