24X National Exchange is revising its trade-cancellation rules ahead of the planned December 6, 2026, expansion of US equity trading to 23 hours a day, five days a week. A Securities and Exchange Commission notice published November 10 details how the exchange intends to handle clearly erroneous transactions during overnight hours, when new price protections are expected to take effect across the market.
The amendments, filed November 3 under SR-24X-2026-31, would extend existing restrictions on erroneous-trade reviews to the overnight session between 9 p.m. and 4 a.m. Eastern Time. Trades executed within valid price bands would generally be protected from subsequent cancellation, subject to specified exceptions.
The filing is immediately effective, although the exchange intends the amendments to become operative when 23/5 trading begins. It is not a new SEC approval of extended trading hours. The underlying overnight price-protection framework received regulatory approval on August 5.
Overnight trading introduces 20% price protections
The new framework introduces temporary price bands initially set 20% above and below specified reference prices for eligible US equities during overnight protected hours.
These protections form part of Amendment 27 to the national Limit Up-Limit Down (LULD) Plan, which the SEC approved in August. Unlike the existing daytime framework, the overnight system initially relies on static price bands.
The approved approach uses two reference points: the listing market’s official closing price and a consolidated price derived from the last eligible round-lot transaction at a specified evening reference time, generally 7:45 p.m. Eastern Time.
The bands are intended to restrict executions outside permitted ranges when overnight liquidity is thinner and conventional daytime price discovery is unavailable.
Still, a 20% range is wide, and an execution inside it might be considerably different from the price a trader expected.
The framework does not guarantee that an investor receives a competitive execution price. It establishes boundaries for permissible trading and provides a basis for deciding which completed transactions qualify for review.
That distinction is particularly relevant after recent problems affecting existing overnight equity infrastructure. In October, a Blue Ocean ATS outage disrupted overnight trading for customers of Bitget and Alpaca, while Binance adjusted calculations used for equity-linked perpetual futures after reporting connectivity problems at an unnamed overnight venue.
Those incidents involved infrastructure availability rather than erroneous-trade determinations, but they illustrate the wider operatonal requirements accompanying the expansion of US equity-market hours.
24X narrows when overnight trades can be cancelled
The central amendment concerns Rule 11.14, which governs clearly erroneous executions.
Under the existing arrangement, transactions executed during regular trading hours generally cannot be cancelled through the clearly erroneous review process when valid LULD price bands were available and correct at execution. Certain exceptions remain, including transactions involving securities outside the LULD framework or circumstances in which price bands were unavailable or a trading halt should have prevented execution.
24X wants to apply the same basic approach to its overnight market session.
Instead of restricting that treatment to regular trading hours, the revised rule introduces the broader definition of LULD Protected Hours, covering both regular and overnight protected sessions.
It is a relatively small change in wording, but the consequences for disputed trades could be rather large.
A transaction executed within applicable overnight protections would generally stand, even if the market subsequently moved sharply or the investor considered the execution unfavorable.
The exchange would retain clearly erroneous review in the specified exceptional circumstances. The proposed amendment also incorporates the overnight percentage parameter into the criteria used when assessing eligible complaints.
Another provision addresses securities not covered by the LULD Plan, including certain rights and warrants. For these instruments, 24X proposes using the numerical review guidelines applicable to pre-market and post-market trading when transactions occur during overnight protected hours.
These are seperate procedures from the general restriction on reviewing trades executed within valid price bands.
The rule works in the other direction too, for transactions that remain eligible for review under the specified exceptions.
The exchange’s November 10 SEC filing, Release No. 34-106867, explains that the amendments seek to reduce inconsistencies between the price-band system and the process for cancelling erroneous transactions.
The regulatory objective is execution certainty. Market participants operating overnight need to know whether completed trades can later be reversed, particularly when the underlying securities may experience large movements following international economic announcements or company-specific developments.
The filing does not introduce a general right to reverse trades simply because their execution prices later prove disadvantageous.
Extended equity trading brings new infrastructure demands
24X’s proposed changes form part of a coordinated industry effort rather than an isolated exchange initiative.
The November filing states that other national securities exchanges and the Financial Industry Regulatory Authority are expected to adopt substantially similar erroneous-trade provisions.
Comparable amendments have already appeared in filings involving other exchanges, reflecting efforts to establish consistent handling of disputed executions during overnight trading.
Without broadly aligned rules, identical transactions executed on different venues could encounter different cancellation procedures during the same overnight market conditions.
The move also changes the competitive environment for alternative trading systems, which already facilitate overnight access to US equities.
Exchange-based overnight trading will operate within the national market structure, supported by consolidated market data, regulatory protections and exchange-specific rulebooks.
There is another layer to this, though, because the market data must remain availble and accurate throughout the longer session.
Recent disruptions provide evidence of the practical difficulties. DaveFinances previously reported that CMC Markets experienced a two-hour US securities pricing disruption on October 21 affecting its 24/5 offering after problems involving an external pricing provider.
The broker did not establish that any trades were executed incorrectly. The incident nevertheless demonstrated the dependence of overnight products on reliable external market-data services.
The expansion is also taking place alongside the development of alternative structures for trading traditional assets outside conventional market hours. These include tokenized equity markets using automated liquidity pools, where execution and price formation can differ substantially from the order-book framework used by regulated stock exchanges.
For securities brokers and market makers, the distinction involves more than the number of hours a product is tradable. Different venues may impose different execution protections, order-handling procedures and rules for resolving contested transactions.
December 6 remains the target for 23-hour trading
Industry-wide implementation of extended equity trading is scheduled for December 6, 2026, with the overnight protected session running from 9 p.m. to 4 a.m. Eastern Time.
The intended structure provides 23 hours of trading availability on each trading day, leaving a one-hour interval for operational processing and system maintenance.
The expansion also depends on the infrastructure responsible for collecting and distributing consolidated securities-market information.
The SEC previously granted 24X conditional relief addressing the possibility that the national market-data plans might not be ready by December 6. That contingency would not permit the exchange to bypass those requirements immediately. The relief is scheduled to become effective January 24, 2027, if the relevant conditions are met.
The date is on the calendar, but several pieces of the market infrastructure still have to line up with it.
Separately, the November 3 erroneous-trade filing became effective under the Exchange Act’s self-regulatory organization rulemaking provisions. The SEC retains the authority to temporarily suspend the change within 60 days of filing if it determines that doing so is necessary or appropriate under the applicable statutory standards.
The Commission is also soliciting public comments, leaving an additonal opportunity for market participants to raise concerns about the proposed arrangements.
For brokers preparing to connect to 24X’s overnight session, the operational requirements extend to recognizing the applicable price bands, understanding when clearly erroneous review is permitted and ensuring that order-management systems handle overnight executions according to exchange rules.
The next milestones are the expected December 6 introduction of extended trading and the application of the revised cancellation framework once trading begins. The new filing establishes how 24X intends to treat disputed overnight executions; whether the wider market infrastructure is ready for the scheduled expansion remains a seperate implementation question.
Johan Shamshad is Editor-in-Chief at Dave Finances, covering financial markets, digital assets, trading platforms, brokers, fintech, payments and regulation. Since 2023, he has also worked as an editor at Gulf News, the UAE English-language newspaper published by Al Nisr Publishing LLC. His work focuses on market-moving developments, company disclosures, regulatory changes and trading infrastructure, with an emphasis on primary-source verification and practical context for traders and investors.