ap photo This 2020 photo shows the logo for the Robinhood app on a smartphone in New York. Robinhood’s debut as a publicly traded company will be the biggest test yet of whether giving ordinary investors early access to a big slice of a company’s initial public offering can pay off.

LOS ANGELES — Robinhood is disrupting another stock market norm — and taking a big risk — by giving ordinary investors access to a huge slice of its initial public offering.

The popular online brokerage is taking the unusual step of allowing users of its trading app to buy up to a third of its IPO shares before they begin trading on the Nasdaq Thursday under the “HOOD” ticker symbol. Typically, only institutional investors and company insiders can buy shares in companies before they go public.

Early access can potentially give investors a big advantage if shares move higher once they debut. Between 2001 and 2020 the average U.S. IPO returned 14.5 percent from the offer price on day one, according to Renaissance Capital. So far this year, the jump is even greater, at 34 percent. For IPOs that have raised at least $100 million, the average first-day return this year is 25 percent.

But expanding early access beyond Wall Street insiders isn’t without risk, especially given that Robinhood is making available such a large chunk of its offering to users via its own trading platform. The move could backfire if many individual investors, often referred to as retail traders, flip their shares for a quick profit, rather than hold them, said Matt Kennedy, senior IPO market strategist at Renaissance Capital.

“The major downside, and the reason this is so unusual, is issuers typically place a great deal of value on the investment bank’s ability to place the shares with institutional, long-only investors who understand the business, believe in it and have done their homework,” Kennedy said. “Retail traders have more of a reputation of flipping, so this could result in higher volatility.”

The Menlo Park, California, company expects to offer up to $770 million worth of its shares to its customers. The estimate is based on an offering price of $40 per share, the midpoint in a range of $38 to $42 per share, the company said a filing with the Securities and Exchange Commission last week. All told, Robinhood is seeking a market valuation of up to $35 billion.

While giving individual investors a shot at pre-IPO shares is unusual, there have been some high-profile examples in recent years.

Ride-hailing apps Uber and Lyft gave their drivers a way to buy IPO shares, while online marketplace Etsy let its users get a piece of its IPO. Some companies also elect to go public via what is known as a direct listing. That’s where a company sells its shares to the public without involving underwriters. So, essentially everyone is on equal footing.

Robinhood’s approach stands out mainly because it is setting aside up to 35 percent of the IPO shares for its users. That’s the largest portion by far of pre-IPO shares to be designated for retail investors in an underwritten offering, Kennedy said.

Robinhood recently rolled out IPO Access, a platform that allow users to get in early on IPOs. The first such IPO made accessible to Robinhood users was Figs’ stock market debut in May. Shares in the online scrubs seller soared 36 percent in their first day of trading.

Robinhood users interested in buying shares of the company via its platform must sign up for the IPO Access feature. Once there, they place a “conditional offer to buy,” or COB, and say how many shares they hope to purchase. That conditional offer doesn’t become an official order until the IPO is priced, likely Wednesday night.

Robinhood has warned that users of IPO Access may get the full number of shares they want, or a partial amount, or none at all, depending on demand and other factors.