For decades, the 4:00 p.m. closing bell has given compliance teams a clean dividing line. Pre-clearance approvals lapse at the close, blackout periods start or finish, restricted-list updates take effect, and employees understand exactly when permission to trade runs out. That certainty is about to disappear.
From December 6, 2026, Nasdaq and NYSE intend to run a trading schedule stretching from 9:00 p.m. ET on Sunday through to 8:00 p.m. on Friday, punctuated only by a planned one-hour maintenance break each evening, according to StarCompliance.
The market will technically still close, but the pause amounts to little more than a brief rest. Across the Atlantic, the London Stock Exchange has signalled that its LSE24 initiative is set to launch in the first half of 2027. With equities trading 23 hours a day, firms must ask what “market close” actually means for compliance.
The implications go well beyond longer hours. At the SEC’s September 17 roundtable on preparing for 24-hour trading, discussion ranged across overnight surveillance, clearing and settlement, investor protection, cybersecurity, staffing, systems resilience and market-data continuity.
Commissioner Hester Peirce also flagged concerns about supervision, thinner overnight order books, wider spreads and the practical difficulty of handling problems at 3:00 a.m. For compliance functions, this is not simply an additional session. It undermines assumptions built into policies and controls designed around a clearly defined trading day.
Overnight trading is still modest but accelerating fast. SEC figures show it represented only 0.9% of National Market System share volume in August 2026, yet average daily overnight volume rose 359% year on year to roughly 144.6m shares, with over 4,200 NMS stocks changing hands overnight on a typical day. The real compliance concern is not the volume itself, but whether staff can trade during windows that current policies, approvals and surveillance were never built to cover.
The new schedule shows how quickly definitions blur. The Night Session will run from 9:00 p.m. to 4:00 a.m. ET, followed by Pre-Market, Regular Market Hours and Post-Market trading until 8:00 p.m.
Trades executed between 9:00 p.m. and midnight will even carry the following day’s trade date. Imagine an employee granted approval at 10:00 a.m. that is valid “until market close.” Does that end at 4:00 p.m. or 8:00 p.m.? Could they trade once the Night Session opens? And what happens if a blackout or restricted-list change lands between sessions?
To prepare, compliance teams should address five questions. Which policies rely on terms such as “market close,” “trading day” or “business day”? How long should pre-clearance remain valid, and when should restrictions apply across every session and market? Can existing systems correctly capture overnight activity and its trade date? Will the firm itself trade around the clock, and how must controls adapt? Finally, who handles exceptions arising outside normal compliance hours?
Compliance teams need not work 23 hours a day, but their controls must reflect a market that does. With further expansion of trading hours likely, firms should treat this as a lasting structural shift rather than a one-off configuration task. The closing bell remains, but its role as a compliance boundary is fading.
StarCompliance’s full post can be viewed here.
Copyright © 2026 RegTech Analyst
Copyright © 2026 RegTech Analyst
