Executive Summary
- What’s new: Beginning December 6, 2026, both the Nasdaq Stock Market and NYSE Arca are expected to extend trading hours to 23 hours per day, five days per week (23x5 trading).
- Why it matters: The 23x5 trading expansion would add an overnight session from Sunday through Thursday from 9 p.m. to 4 a.m. ET, with a mandatory one-hour trading pause Monday through Thursday evening between 8 p.m. and 9 p.m. ET.
- What to do next: Companies should consider the potential impacts on corporate policies and transaction documents that reference exchange-defined trading sessions and monitor disclosure practices in light of 23x5 trading.
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On April 10, 2026, the U.S. Securities and Exchange Commission (SEC) approved a proposal by the Nasdaq Stock Market (Nasdaq) to extend trading hours to 23 hours per day, five days per week (23x5 trading). The SEC’s approval of Nasdaq’s proposal was followed by NYSE Arca’s amended rule filing submitted on May 12, 2026, describing the exchange’s operational framework for 23x5 trading. Both Nasdaq and NYSE Arca are targeting a December 6, 2026, launch of their extended 23x5 trading hours.
The exchanges currently support three trading sessions from Monday through Friday: 4 a.m. to 9:30 a.m. ET, 9:30 a.m. to 4 p.m. ET, and 4 p.m. to 8 p.m. ET. With the 23x5 trading expansion, Nasdaq and NYSE Arca would add an overnight session from Sunday through Thursday from 9 p.m. to 4 a.m. ET, with a mandatory one-hour trading pause Monday through Thursday evening between 8 p.m. and 9 p.m. ET. This mandatory trading pause enables the exchanges to conduct maintenance and testing and to process dividends, stock splits and other corporate actions pending for the next trading day. The trading week would begin with the night session on Sunday at 9 p.m. ET.
Only U.S. broker-dealers that are members of Nasdaq and NYSE Arca may trade during the overnight session. Retail investors or other firms may only trade on the overnight session through a member of each respective exchange. Trades executed between 9 p.m. and midnight ET will carry the next calendar day’s trade date, and settle one day later. Trades between midnight and 4 a.m. ET will carry that day’s trade date.
Trading Sessions Under Nasdaq and NYSE Arca
While Nasdaq’s and NYSE Arca’s changes result in 23x5 trading from 9 p.m. ET Sunday through 8 p.m. ET Friday, the two exchanges have structured their sessions differently. NYSE Arca will operate four distinct sessions, with an overnight session from 9 p.m. to 4 a.m. ET. NYSE Arca’s current timing of the Early, Core and Late Sessions will not change. By contrast, Nasdaq will operate two sessions only: a Night Session from 9 p.m. to 4 a.m. ET and a Day Session from 4 a.m. to 8 p.m. ET that consolidates what are now the Pre-Market Hours, Regular Market Hours and Post-Market Hours into a single session.
The following table outlines current and future trading sessions on each exchange.
| NYSE Arca | Nasdaq | ||
|---|---|---|---|
| Current Sessions | Trading Hours | Current Sessions | Trading Hours |
| Early Session | 4 a.m. to 9:30 a.m. ET | Pre-Market Hours | 4 a.m. to 9:30 a.m. ET |
| 9:30 a.m. to 4 p.m. ET | |||
| Core Session | 9:30 a.m. to 4 p.m. ET | Regular Market Hours | |
| Late Session | 4 p.m. to 8 p.m. ET | Post-Market Hours | 4 p.m. to 8 p.m. ET |
| Future Sessions | Trading Hours | Future Sessions | Trading Hours |
| Overnight Session | 9 p.m. to 4 a.m. ET | Night Session | 9 p.m. to 4 a.m. ET |
| Early Session | 4 a.m. to 9:30 a.m. ET |
Day Session | 4 a.m. to 8 p.m. ET |
| Core Session | 9:30 a.m. to 4 p.m. ET | ||
| Late Session | 4 p.m. to 8 p.m. ET | ||
Certain core market conventions nevertheless will remain unchanged. For Nasdaq-listed companies, the traditional U.S. trading hours, from 9:30 a.m. to 4 p.m. ET and marked by the Opening and Closing Crosses, will continue to set the prices to drive investor transparency across all hours of market operation. In addition, the regular market on NYSE Arca’s Core Session will continue to open at 9:30 a.m. ET, and the exchange will still publish its Official Closing Price following the Core Closing Auction at 4 p.m. ET.
Corporate Action Information
With the introduction of 23x5 exchange trading, there will only be a one-hour trading pause between 8 p.m. and 9 p.m. ET, which may not be sufficient for the processing of complex corporate actions across exchange and market participant systems. To address this, the primary listing markets will impose mandatory halts on the affected security for the duration of the overnight session until 8 a.m. ET on the effective date of the corporate action, effectively preserving the pre-23x5 status quo for these events.1
Practical Considerations for Companies
The move to extended trading raises several practical considerations for companies, including:
- Insider trading and other corporate policies: Consider whether existing insider trading policies and trading window procedures require amendment in light of the new overnight session. For companies listed on the New York Stock Exchange, whose policies are tied to the preserved Core Session (9:30 a.m. to 4 p.m. ET), the overnight session may require little or no policy change. For Nasdaq-listed companies, the consolidation of pre-market, regular and post-market hours into a single Day Session (4 a.m. to 8 p.m. ET) may shift the meaning of policy terms like “market hours,” “market close” and “trading day.” Those companies should consider whether their insider trading policies and trading windows should reference specific hours rather than exchange-defined sessions.
Nasdaq-listed companies also should consider reviewing other corporate policies and equity plans that reference exchange-defined sessions, which may have shifted under Nasdaq’s consolidated two-session structure. For instance, it may be advisable for companies to clarify how certain aspects of their equity plans or policies will be interpreted in light of 23x5 trading, particularly for Nasdaq-listed companies’ equity plans that reference exchange-defined sessions (e.g., using “closing sales price” in the Fair Market Value definition). - Disclosure practices: Longer trading days may have implications for how and when companies communicate material information to the market, including the timing of SEC report filings and press releases. For example, in his introductory remarks at the SEC’s “Roundtable on Preparations for 24-Hour Trading,” Chairman Paul Atkins encouraged issuers to provide feedback on how expanded trading hours may affect their obligations to disseminate material information to the market and the obligation to make SEC filings during EDGAR filing hours. Commissioner Hester Peirce echoed these comments in her opening remarks, noting that issuers currently make filings and publicize material information prior to or after core trading hours. She questioned whether companies may need to reconsider long-standing practices for timing material announcements as trading expands beyond core hours and whether the SEC may need to modify EDGAR to ensure that material information can be disseminated in a timely manner during the overnight session.
- Transaction documents: Many agreements and offering documents contain terms that were drafted with traditional trading hours in mind. Companies should consider whether definitions, conditions and timing provisions would need to be modified for this new 23x5 trading environment. For instance, definitions of “trading day,” “market close” and “Volume-Weighted Average Price” may no longer work as intended under the 23x5 trading framework.
- Market dynamics: Extended trading could change the landscape in which capital markets transactions are structured. Shifts in trading patterns and market behavior during nontraditional hours may affect transaction strategy and risk assessment.
What Happens Next
Several rules necessary to implement the 23x5 trading framework remain subject to SEC approval. Companies should expect further technical and fee-related filings as the December launch date approaches. Companies cannot opt out of their stock trading during the new 23x5 hours starting December 6, 2026, and should monitor developments related to 23x5 trading and prepare for their potential impact on corporate policies, documents and disclosure practices.
For more information, see Nasdaq’s Frequently Asked Questions (FAQ) on Global Trading Hours and Corporate Action Mandatory Regulatory Halt Rules and NYSE Arca’s FAQ on Extended Hours Trading.
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1 The following nine categories of corporate actions are subject to a mandatory corporate action halt: (1) changes in trading symbol; (2) changes in CUSIP number; (3) large dividends; (4) stock splits (including forward and reverse splits); (5) de-SPAC transactions; (6) spin-off transactions; (7) security type change (e.g., preferred to common); (8) mergers and similar mandatory exchanges of shares; and (9) any other corporate action or issuer-related event where the primary listing market determines that a regulatory halt is appropriate for the maintenance of fair and orderly markets, the protection of investors or otherwise in the public interest.
This memorandum is provided by Skadden, Arps, Slate, Meagher & Flom LLP and its affiliates for educational and informational purposes only and is not intended and should not be construed as legal advice. This memorandum is considered advertising under applicable state laws.