There’s a new darling on Wall Street: private markets.

Because that’s where the party is now. Companies are staying private for longer — the number of publicly traded companies has dropped by nearly half over the past three decades, with nearly 1,500 start-ups worldwide currently boasting a valuation of $1 billion or more — and, according to the global consultancy Bain & Company, private market assets have more than tripled since 2013. The firm expects them to grow twice as fast as public assets in the future, reaching $62 trillion globally by 2034.

Historically, private equity investments were accessible only to wealthy and experienced investors. But in recent years, interest has soared among the retail class.

Fund managers, brokerage houses and savvy start-ups are racing to build new products that expand access to all, and the newly appointed chairman of the Securities and Exchange Commission, Paul S. Atkins, has signaled he supports the goal.

“This is just the beginning,” said the senior vice president of Robinhood Crypto, Johann Kerbrat, who is leading Robinhood’s efforts to make private equity tradable on its platform.

Washington appears to be on board. Investments in private companies have typically been reserved for “accredited investors” — people that earn more than $200,000 a year or have a net worth of at least $1 million. The requirement is meant to protect everyday investors from high-risk investments “There’s not a lot of clarity, you can’t get your money out, and you might lose all your money,” said Jonathan Foster, the C.E.O. at Angeles Wealth Management.