Ringing the opening and closing bell on the New York Stock Exchange or Nasdaq is a time-honored tradition—and a major honor for companies and executives who get to participate in the ceremony. The ritual, however, may be declining in significance as around-the-clock trading becomes the norm on Wall Street and throughout the world.

This fundamental shift hit a milestone late last month when the aptly named 24 Exchange became the first exchange operator to gain SEC approval for overnight trading. The company is now looking to raise $50 million, Axios reported, ahead of its planned launch next year.

The move comes as other popular brokerages like Robinhood already offer 24-hour trading—allowing retail investors to wade into a domain previously reserved for hedge funds and other major institutional players. In October, the NYSE announced it would file with the SEC to run 22-hour weekday sessions as markets adjust to a globalized and digital world.

Popular stocks like Tesla, Nvidia, and Apple can swing big in either direction before or after the bell, particularly off the back of earnings releases or other major news events like, say, presidential elections. In that sense, it’s obvious why many investors don’t want to be limited to buying and selling from 9:30 a.m. to 4 p.m.

After all, they can trade cryptocurrencies 24 hours a day, and the same is true for foreign exchange markets. Making moves outside normal trading hours, however, comes with increased risks that equity investors need to understand.

In fact, similar drawbacks apply to extended trading hours currently offered by the major U.S. stock exchanges, which investors can participate in through many retail brokerages. The NYSE and Nasdaq both have premarket sessions from 4 a.m. to 9:30 a.m. The former is open for after-hours trading from 4 p.m. to 8 p.m., while the latter closes shop at 6:30 p.m.

For all of these nontraditional trading periods, it’s important to know that trading volumes are much lower during these sessions, meaning prices can swing more quickly and dramatically as investors try to expand or exit their positions.

“Investors trade with no commissions today—but they effectively pay commissions in the form of a spread,” Richard Torrenzano, a former member of the NYSE’s policy and operations committees, explained in a recent Fortune opinion piece.

Those spreads, or the gap between buying and selling prices for a stock, often widen in extended trading and can eat into profits. In other words, lower liquidity means investors are often better off when they wait for the core trading session.

Why is the SEC a fan of 24/7 trading?

The Securities and Exchange Commission, including outgoing chair Gary Gensler, unanimously gave 24 Exchange the green light to move forward with around-the-clock trading operations. This suggests they share the view of proponents, who say regulated overnight trading could potentially make markets more transparent.

Currently, institutions often use an alternative trading system, or ATS, to find counterparties for big transactions outside typical exchanges. Hedge funds, especially, favor so-called dark pools, which are mostly run by investment banks and allow investors to trade large blocks of shares away from public view.

In a statement announcing 24 Exchange’s approval, SEC commissioners Hester Peirce and Caroline Crenshaw claimed overnight sessions on a lit exchange, effectively the opposite of a dark pool, could make trading more convenient for both U.S. and foreign investors.

“It potentially will draw more participants into our markets,” they wrote.

In his Fortune opinion piece, however, Torrenzano said he doubts there will be such a shift. Stocks such as Apple, Microsoft, Amazon, Meta, Oracle, Visa and Mastercard, JPMorgan, and Exxon, he said, already trade outside U.S. market hours through dual listings on exchanges in Tokyo, London, and elsewhere.

“In the absence of this commanding presence or a yet unidentified magnetic force, enticing non-U.S. investors to engage in U.S. stock trading during off-market hours appears exceedingly challenging,” he wrote, “particularly when they can trade in their home market, protected by local oversight, when U.S. markets are closed.”

For American retail investors, however, overnight trading likely represents a meaningful shift. Starting in the second half of 2025, 24 Exchange plans to operate from 4 a.m to 7 p.m on U.S. business days. It then aims to expand to 23-hour weekday trading, which will run from 8 p.m. on Sundays through 7 p.m. on Fridays.