US stock exchanges are actively weighing a shift to 24/7 trading, and the debate has narrowed to two core questions: whether nonstop access would make markets fairer for retail investors, and whether thin liquidity outside traditional sessions would leave prices easier to distort.
Supporters say closed markets hand pricing power to a small group
Mati Greenspan, founder and CEO of Quantum Economics, argues that round-the-clock trading would be especially beneficial for individual investors. In his view, brokers have long benefited from after-hours market closures by using those windows to shape prices and profit from investor losses. When major news breaks over a weekend or holiday and markets remain shut, only a limited number of institutions can influence where stocks open next.
Greenspan said prices are easier to influence when markets are closed. That can lead to sharp opening moves after major weekend developments. In simple terms, price discovery gets delayed, then released all at once when the bell rings.
Thin off-hours volume can widen spreads and distort pricing
Joe Dente of the New York Stock Exchange said lower transaction volume outside normal market hours tends to widen bid-ask spreads and amplify volatility. For traders, the issue is not just that prices move more. It is that shallow depth can make execution less reliable, with actual fills landing far from quoted prices.
Academic work points in the same direction. Joint research from UC Berkeley and the University of Rochester found that thin volume and restricted liquidity during off-hours make price discovery less efficient, slowing the process by which new information is absorbed into stock prices. News may be public already, yet the market may still struggle to produce a stable reference price.
Regulators are focused on spoofing-style behavior and surveillance gaps
As continuous trading becomes a more serious possibility, concerns over volatility and manipulation have moved back to the front. Dente warned that these risks may not fade in a 24-hour market; in periods of weak liquidity, prices may become even easier to push artificially.
A recent SSRN study documented cases where some brokerages placed large buy or sell orders just before the opening bell and then canceled them before execution, a tactic aimed at moving prices up or down without completing the trade. The US Securities and Exchange Commission has also fined firms including Velox Clearing millions of dollars for using misleading orders to create price swings.
FINRA has called for stronger surveillance and reporting systems, with particular attention on periods outside regular trading hours. Market analyst Pranav Ramesh shares the concern, saying off-hours markets are more vulnerable to erratic price action and make it harder for retail traders to find dependable pricing benchmarks. If major events occur while markets are closed, brokers gain a larger role in setting the tone for the next open.
Crypto-based venues already offer a live model for nonstop markets
Platforms built on cryptocurrency and blockchain infrastructure have already shown how uninterrupted trading can attract volume, especially during periods of global turmoil. The decentralized platform Hyperliquid is one example. According to the report, it has exceeded $50 billion in weekly derivatives volume and reached $1.6 million in daily income, helped in part by the launch of perpetual futures tied to the S&P 500 index.
That growth gives traditional equity markets a working reference point, but it does not settle the main dispute. If US stocks do move toward full-time trading, the real test will not be the longer trading window alone. It will be whether supervision, transparency, and execution quality can hold up across every hour of the day.