Nasdaq launches 23/5 trading on December 6, with only 1 hour of market closure per day.

on November 3, according to information on the Nasdaq official website, Nasdaq will officially launch the "23/5" trading system at 9 p.m. Eastern Time on December 6 (Sunday), extending U.S. equity trading to five days a week and 23 hours a day.

The new system introduces an overnight session from 9 p.m. to 4 a.m. ET, which combines with the existing pre-market (4 a.m. to 9:30 a.m.) and post-market (4 p.m. to 8 p.m.) sessions to form a "global trading session." Trading will proceed from Sunday at 9 p.m. through Friday at 8 p.m., with a one-hour daily pause from 8 p.m. to 9 p.m. for system maintenance, corporate action processing, and the transition between trading days.

The regular trading session from 9:30 a.m. to 4 p.m. ET and the opening and closing auctions remain unchanged, with the closing price continuing to serve as the official benchmark. Trades executed between 9 p.m. and midnight will be recorded on the following trading day, while settlement rules remain unchanged. On the risk management front, the SEC has approved revisions to the relevant LULD plan, stipulating that overnight session orders must fall within a price band of 20% above or below the reference price.

Nasdaq stated that the launch remains contingent upon the readiness of the Securities Information Processor (SIP) and related SEC rule changes.