Nasdaq Advances 5x23-Hour Trading Initiative in Formal SEC Filing

The evolution of equity market hours is accelerating. Nasdaq is moving forward with an ambitious restructuring of market access by preparing to submit its 5x23 trading framework to the U.S. Securities and Exchange Commission. This development, reported in mid-December, represents a fundamental shift in how stocks and exchange-traded products (ETPs) will be accessible to investors, transitioning from the current model of 16 trading hours spread across five weekdays to a significantly expanded 23-hour daily schedule.

Expanding Market Windows: From 16 to 23 Hours Daily

The current trading landscape operates within defined boundaries—regular sessions bookended by pre-market and after-hours windows. Nasdaq’s new proposal shatters these constraints by introducing what it terms the 5x23 model, essentially creating five full days of nearly round-the-clock market access. The shift fundamentally changes the investor experience by eliminating lengthy gaps between trading days and enabling continuous price discovery across extended time windows.

The extended trading architecture will maintain the familiar daytime framework—running from 4:00 AM through 8:00 PM Eastern Time—while anchoring the established regular trading session opening at 9:30 AM and closing at 4:00 PM. Pre-market and after-hours sessions will continue within this daytime window, preserving the market structure investors already understand.

The Night Session: A New Trading Frontier

The truly innovative component of the 5x23 plan introduces a night session running from 9:00 PM to 4:00 AM the following calendar day. This eight-hour window would capture trades executed between 9:00 PM and midnight, attributing them to the subsequent trading day. The arrangement effectively creates overlapping trading days, enabling traders in different time zones and operating schedules to execute positions during their local business hours.

Operational Timeline: When the Markets Go Live

Under Nasdaq’s proposal, the trading week will commence at 9:00 PM on Sunday evening, immediately before the night session begins. The structured calendar will continue through the daytime sessions, ultimately concluding at 8:00 PM on Friday following the final daytime trading window. This creates a seamless weekly cycle where market participants can engage across Sunday evening through Friday evening—a dramatic expansion compared to today’s Monday-through-Friday framework.

The 5x23 trading model represents more than a scheduling adjustment; it signals a market infrastructure designed for global participation and continuous capital flow. As Nasdaq moves through the formal SEC approval process, market participants will be watching closely to understand how this extended access reshapes trading behavior and market dynamics.