Nasdaq Seeks to Expand Trading Hours, Embrace Near Round the Clock Markets

Nasdaq Inc. moved on December 15 to seek regulatory approval to extend trading on its stock venues to nearly round the clock hours, filing with the Securities and Exchange Commission to expand trading from about 16 hours a day to 23 hours a day, five days a week. The proposal would split trading into a long day session and a night session separated by a one hour maintenance break each evening.

Under the filing Nasdaq outlined a day session running from 4:00 a.m. Eastern Time to 8:00 p.m. Eastern Time that would continue to encompass pre market, regular market and post market trading periods, with the familiar opening bell at 9:30 a.m. Eastern Time and closing bell at 4:00 p.m. Eastern Time retained. The exchange proposed an 8:00 p.m. to 9:00 p.m. Eastern Time pause for testing, maintenance and clearing, followed by a night session from 9:00 p.m. Eastern Time to 4:00 a.m. the next calendar day. Trades executed between 9:00 p.m. and midnight during the night session would be attributed to the following trading day. The new trading week would begin on Sunday at 9:00 p.m. Eastern Time and end on Friday at 8:00 p.m. Eastern Time. The expansion would apply to stocks and exchange traded products.

Nasdaq said the plan was designed to capture growing global demand for U.S. equities and to accommodate investors outside the United States, notably in Asia, who increasingly seek overnight access to U.S. markets. Nasdaq data cited in the filing shows foreign holdings of U.S. equities reached about 17 trillion dollars last year, a statistic the exchange argues supports a case for broader access. The filing also framed the change as a way to compete for order flow and to position trading venues to interact with markets that already operate continuously.

Market participants and infrastructure providers reacted cautiously. Major Wall Street banks have warned that a move toward near round the clock trading could produce thinner liquidity in off hours, greater intraday volatility and uncertain returns on the substantial investments required to run systems, staff trading desks and support clearing around the clock. Clearinghouses and brokers would face new operational burdens, including extended settlement windows, expanded surveillance and risk controls and the need to staff monitoring and margin operations across more hours.

Long term, the proposal reflects a broader shift in market structure toward globalized trading hours, and a convergence in market practices between traditional equities and digital asset platforms that already trade without interruption. But volume patterns present a constraint. Extended hours trading historically accounts for a small fraction of daily volume, although Nasdaq said it has observed growing interest in overnight sessions among non U.S. investors.

The filing now moves to the SEC for review, and it is not yet clear whether the commission has accepted the filing or will open a public comment period. Regulators will need to weigh surveillance capacity, clearing resilience and investor protection as they consider whether to permit a far longer trading day for U.S. equities. For investors, brokers and market makers, the decision could reshape when price discovery occurs and how liquidity is provisioned across time zones.