A bell at 9:30 a.m., another at 4:00 p.m.: this widely publicized ritual that has governed trading on Wall Street for over a century could lose its luster. The American stock exchange wants to move to 24/7 trading, which appeals to smaller investors.

The New York Stock Exchange (NYSE) announced earlier this week its intention to open a platform allowing "24-hour, seven-day-a-week trading" and "instant settlement", without specifying when.

These transactions, which have no time limit, will rely in particular on the issuance of digital tokens ("token") replicating the shares of companies listed on the Stock Exchange, Intercontinental Exchange, parent company of the NYSE, indicated in a statement.

Nasdaq, another trading platform in New York, particularly for listing technology companies, could take the plunge as early as this year, with 24-hour operation, five days a week.

These ambitions still need to be validated by the US stock market regulator, the SEC, but they constitute a small revolution for the American stock market.

"Waste of time"

Originally, investors "had to physically go" to Wall Street to buy or sell shares, Sam Burns, chief strategist at Mill Street Research, told AFP.

"A lot of things were done on paper, people stood up and shouted at each other (...), then they had to write down what each person had bought and sold" and tally it all up, a pace "impossible to keep up with" if the hours were too long, according to him.

But over the decades, electronic transaction platforms have been created, allowing in particular for trading outside of conventional hours, with increasing success.

According to a document published in early 2025 by the New York Stock Exchange, "out-of-hours trading volume has increased considerably" since 2019 and even "exploded" since 2024, with a "daily average of more than $61 billion".

But for economics professor Steve Hanke, the interest remains limited.

"Historically, the idea that the benefits of 24-hour trading outweigh its costs is poorly supported," says the professor at Johns Hopkins University in Baltimore, in the northeastern United States.

"There are few events likely to influence the New York Stock Exchange market that occur outside of normal business hours," he adds, pointing to a "waste of time."

According to him, the only advantage of the NYSE's announcement lies in the time required to finalize a transaction. Currently, on most stock markets, a buy order is only settled the following day, to allow time to verify that everything is in order.

"The reduction of the settlement window could become an advantage" for New York compared to other financial markets, Mr. Hanke believes.

Attracting foreigners and young people

The American market remains by far the most important in the world, particularly due to the immense market capitalizations it hosts. But it is seeing increased competition.

Last year, a large proportion of European indices generated returns that outperformed their American counterparts.

With extended trading hours, Wall Street can hope to broaden its audience to include smaller investors, including those outside the American continent.

According to the Treasury, nearly 18% of US stocks were held by foreigners in 2024, the latest figures available.

New day traders, "especially younger ones, seem to appreciate the idea of being able to trade shares at any time, as they do with cryptocurrencies and other digital assets, whether it's at night or on weekends," adds Sam Burns.

Their impact on prices, however, could remain limited. According to Mr. Burns, investors with large portfolios are not necessarily interested in these extended hours. And banks are unlikely to change their schedules.

"Thus, the analyst argues, even if the stock exchanges are open (continuously, editor's note), if everything else doesn't operate 24 hours a day, seven days a week, it becomes difficult to align everything properly."

AFP