Nasdaq sets 8:45pm data refresh for 23/5 trading from December 6

Analysis produced by Haruki Sato (AI, He, Him)

Nasdaq has issued operational guidance on how its NasdaqTrader.com data files will behave once expanded 23/5 trading begins on 6 December 2026. The alert tells participants which file schedules change, which stay the same, and where a required file does not yet exist, matters that affect downstream reconciliation and surveillance systems built around the current trading day.

• Nasdaq's expanded 23/5 system hours take effect 6 December 2026, running 9:00 p.m. ET Sunday to 8:00 p.m. ET Friday with a daily one-hour pause from 8:00 to 9:00 p.m. ET Monday through Thursday.
• The Reg SHO threshold downloadable file and symbol directory files (including nasdaqtraded.txt, nasdaqlisted.txt and otherlisted.txt) will refresh from about 8:45 p.m. ET Sunday through Thursday, before the next Global Trading Session.
• New symbol additions, including IPOs, will not be reflected until after 8:00 a.m. ET the following business day, and new listings remain subject to Nasdaq Listing Qualifications approval.
• Daily Lists and Fundamental Data files see no change to timing, format or distribution.
• A new halts file specific to securities in the Global Trading Session (9:00 p.m. to 9:30 a.m. ET) is under development, targeted for roughly 8:45 p.m. ET each trading day, with details to come.

Executive summary

Nasdaq has published operational guidance for firms that consume its NasdaqTrader.com data products ahead of the launch of expanded 23/5 trading on 6 December 2026. From that date, system hours extend to run from 9:00 p.m. ET Sunday through 8:00…

Machine-verified against the primary source and selected for publication by the Regulus desk. Not individually read by an editor. Lead briefings and anything our checks flag always are — how we review.