US 23x5 Overnight Trading Set for Dec. 6 Launch: Firm Readiness Steps
Exchange and SIP approvals, overnight price bands, corporate-action halts and a Sunday-evening session all converge on December 6, 2026, giving firms a fixed deadline to rebuild overnight compliance.
US national securities exchanges are positioned to begin 23x5 trading on December 6, 2026, adding an overnight session from 8:00 pm to 4:00 am Sunday through Thursday, with a mandatory one-hour trading pause before the Monday-Thursday evening session. The SEC has conditionally approved 24X, Cboe EDGX, MEMX, Nasdaq and NYSE Arca; launch remains contingent on the consolidated equity data plans (CTA, CQ and UTP) being ready. The SEC approved SIP plan amendments on June 26, 2026 (9:00 pm Sunday to 8:00 pm Friday), NSCC cleared overnight trading from June 29, FINRA trade reporting facilities extend to the same window, and CAT has redefined the industry-member Trade Date. A LULD Plan amendment approved August 5, 2026 imposes static 20% Overnight Price Bands from 9:00 pm to 4:00 am, with no automatic pauses. Listing markets have adopted harmonized mandatory regulatory-halt rules for nine corporate-action categories, halting affected securities from 8:00-9:00 pm the day before the effective date and reopening at 8:00 am. Counsel should also confirm overnight risk disclosures under exchange rules and FINRA Rule 2265, limit-order-only overnight acceptance, clearly erroneous review standards, and circuit-breaker resumption preserved at 4:00 am. Items to watch: FINRA's pending best-execution guidance request and any post-launch LULD data review.