Bloomberg: US stocks may move toward 24/7 trading, with the all-day market set to undergo a stress test.

According to a Bloomberg report, Nasdaq, the New York Stock Exchange (NYSE), and the London Stock Exchange (LSE) plan to extend trading hours in the coming months, with U.S. equity markets gradually moving toward a model of over 23 hours of daily trading, five days a week. Nasdaq and NYSE Arca are set to launch overnight trading on December 6. Nasdaq intends to add a trading session from 21:00 to 4:00 ET, while NYSE Arca has a similar plan, though its main board trading hours will remain unchanged for now. The LSE, meanwhile, plans to launch "LSE 24" in 2027, allowing trading of some securities between 17:00 GMT and 7:50 GMT the next day. Bloomberg notes that the expansion of U.S. trading hours is primarily driven by growing demand from overseas investors and competition from 24/7 trading platforms such as cryptocurrency and prediction markets. Overnight trading volume in U.S. stocks currently accounts for only about 1% of total volume, but has more than tripled in the 12 months through August 2026, with roughly 37% of that overnight volume coming from non-U.S. investors. However, market participants warn that extended trading hours could lead to lower liquidity in overnight sessions, wider bid-ask spreads, increased price volatility, and higher operational and monitoring costs for brokers and market infrastructure. The U.S. Securities and Exchange Commission (SEC) has approved Nasdaq’s plan to extend trading hours and is currently discussing with market institutions how to ensure market order and liquidity during the extended sessions.