Nasdaq has formally advanced its plan to extend U.S. equities trading to nearly 24 hours a day. On December 15, 2025, Nasdaq filed SR-NASDAQ-2025-106 with the U.S. Securities and Exchange Commission to introduce a new “Night Session,” allowing trading for 23 hours per weekday while reserving a one-hour pause for maintenance and corporate-action processing. For issuers, this marks the beginning of the Exchange Act § 19(b) review process.
The Filing’s Current Status
Nasdaq’s public rule tracker lists the proposal as “Pending” and not yet “Noticed by the SEC for Comment.” In practice, this means the SEC has received the filing but has not yet published the notice that initiates the public comment period.
The SEC Process and Timeline
Under Exchange Act § 19(b), the SEC must publish a notice of the filing “as soon as practicable” to invite written comments. The notice appears on the SEC’s Self-Regulatory Organization rulemaking page and in the Federal Register, typically with a 21-day comment window. Once the notice is published, the SEC generally cannot approve the filing before 30 days have passed. Within 45 days after publication, the SEC must either approve, disapprove, or open formal proceedings—and may extend its review by an additional 45 days.
If proceedings are instituted, the agency has up to 240 days after publication to issue a final order. While the statute allows for “deemed approval” if the SEC fails to act, in practice the SEC always issues an order.
Market Infrastructure Must Be Ready
Even if the SEC approves the rule, overnight trading depends on market infrastructure. Nasdaq’s filing conditions implementation on the readiness of the Securities Information Processor (SIP) for consolidated data during overnight hours and the DTCC’s NSCC clearing system.
NSCC currently plans to transition to a 24×5 schedule by June 28, 2026 (subject to regulatory approval), with client testing beginning January 11, 2026. Nasdaq anticipates adoption of extended hours between late 2026 and 2027. Broker-dealer readiness—including risk management, best execution, surveillance, and staffing—will also determine when full-scale overnight trading can begin.
Anticipated Industry Reactions
Large broker-dealers and custodial banks are likely to raise cost and staffing concerns. Market makers may support expanded access but will advocate safeguards against liquidity fragmentation and wide spreads. Institutional investors, particularly pension funds, may focus on price-discovery quality in low-volume hours. Smaller issuers may see benefits in global visibility but face increased investor-relations and disclosure demands.
Realistic Timelines and Issuer Takeaways
While a fast SEC review is theoretically possible, a mid-to-late 2026 implementation window appears more realistic given the interdependencies among SEC approval, DTCC readiness, and market testing. The SEC, now under Chair Paul Atkins (appointed by President Trump), has emphasized market competitiveness and innovation but has not yet indicated a policy stance on the proposal.
An issuer checklist would include:
- Monitoring the SEC’s publication of the notice and comment deadlines.
- Considering whether to submit a comment letter addressing disclosure, liquidity, and operational implications.
- Reviewing and updating Regulation FD escalation and rumor-response procedures for potential off-hours developments.
In short, 23/5 trading is moving forward, but it is more marathon than sprint. For now, issuers should prepare for an extended transition period as regulatory, clearing, and data systems align for near-continuous market access.
