“Infrastructure has risen to a whole different level,” said CJ MacDonald, founder of Step, a debit card provider for teenagers. Step launched in September and quickly reached a million customers, partly thanks to recommendations from social media influencers like Charli D’Amelio.

In December, Step raised $ 50 million. The company wasn’t looking for more money, Mr. MacDonald said. However, investors called as soon as the app entered the list of the most downloaded financial apps shortly after it was released. The money would come together in a few weeks, he said.

Investors are even demanding to buy into broken stores. Plaid, who agreed to sell to Visa for $ 5.6 billion last year, saw the deal in January after undergoing antitrust scrutiny. Now the fast-growing company is in talks with investors to raise $ 15 billion in funding, said two people knowledgeable about the company, who spoke on condition that they will not be identified because the discussions are confidential . The information previously reported on Plaid’s funding talks.

Sheel Mohnot, an investor at Better Tomorrow Ventures, said the sale price of Plaid to Visa was considered “so amazing” at the time. But now, as several fintech companies are nearing a $ 100 billion valuation, it looks low.

Some caution that the excitement is way ahead of reality.

Robert Le, an analyst at PitchBook, pointed to Affirm’s valuation, which has a market cap of $ 20 billion, or roughly 40 times its annual revenue. This is significantly higher than the value investors typically assign to blue chip financial services companies. American Express, for example, only trades three times its annual turnover.

“I think it’s a little irrational,” said Mr. Le. “In the long run some of these companies will have to fall.”

Some of the startups are already in mounting pain. Chime, a banking start-up, had a series of outages in 2019 leaving millions of customers without access to their money for hours. Some Coinbase customers have stated that they have been banned from their accounts or that they stole their money. And Robinhood faces nearly 50 lawsuits and multiple regulatory investigations after trading in some stocks was suspended during a rush into “meme” stocks in January.