SEC Clears Path for 23-Hour U.S. Equity Trading

The new schedule will see the Securities Information Processors (SIPs) operating five days a week, covering 23 hours daily with a one-hour technical maintenance window each evening. To facilitate this transition, the Plan Operating Committees have scheduled six rounds of User Acceptance Testing starting October 2. These sessions are designed to mirror production conditions, running from 11:00 p.m. ET on Fridays through 12:00 p.m. ET on Saturdays.

Jeff Kimsey, Chairman of the SIP Operating Committees, noted that these test weekends serve as a critical validation phase for market participants. While the technical infrastructure prepares for the December rollout, individual exchanges must still secure specific regulatory approvals for their internal rule changes. Furthermore, listing markets have already filed mandates for overnight regulatory halts to address corporate actions during the expanded hours, ensuring that the shift to near-continuous trading maintains existing transparency standards.