Published on: 2025-12-16
Nasdaq plans to shift to a near-round-the-clock weekday model, enabling US-listed shares to trade for 23 hours daily, five days a week, starting in the second half of 2026, pending SEC approval and industry readiness.
Marketed as "23/5," the proposal preserves the core 9:30 a.m.–4:00 p.m. ET session while adding a true overnight exchange session to capture demand from global investors currently using fragmented off-exchange venues.
This guide covers the 23/5 schedule, changes to trade dates and settlement, Nasdaq's motivations, and key risks for traders, brokers, and long-term investors.
Nasdaq plans to file with the SEC to expand stock and ETP trading from today's 16-hour weekday schedule to 23 hours per day, starting in the second half of 2026, subject to regulatory approval.
The structure will split into two sessions, separated by a one-hour pause:
Day session: 4:00 a.m. to 8:00 p.m. ET
One-hour break: 8:00 p.m. to 9:00 p.m. ET
Night session: 9:00 p.m. to 4:00 a.m. ET (next day)
The Trading Week
Under the proposed model, the exchange week effectively runs:
From Sunday 9:00 p.m. ET
To Friday 8:00 p.m. ET
| Session | Time (ET) | What it includes |
|---|---|---|
| Day session | 4:00 a.m. - 8:00 p.m. | Pre-market + regular + after-hours, with the usual 9:30 open and 4:00 close remaining unchanged. |
| Pause | 8:00 p.m. - 9:00 p.m. | Market-wide operational break. |
| Night session | 9:00 p.m. - 4:00 a.m. | New overnight trading window intended to serve Asia and other time zones. |
Today, most investors think of US stocks as trading from 9:30 a.m. to 4:00 p.m. ET, but Nasdaq already operates extended sessions:
Pre-market from 4:00 a.m. to 9:30 a.m. ET
Regular session from 9:30 a.m. to 4:00 p.m. ET
After-hours from 4:00 p.m. to 8:00 p.m. ET
That totals roughly 16 hours, which still leaves a large overnight gap where only certain alternative venues or broker-specific programmes provide limited access.
Under Nasdaq's plan, the new trading day becomes two continuous blocks:
Day session: 4:00 a.m. to 8:00 p.m. ET
Technical pause: 8:00 p.m. to 9:00 p.m. ET
Night session: 9:00 p.m. to 4:00 a.m. ET (into the next calendar day)
The day session still contains the familiar landmarks:
Opening bell: 9:30 a.m. ET
Closing bell: 4:00 p.m. ET
Nasdaq's new trading week would:
Start: Sunday at 9:00 p.m. ET
End: Friday at 8:00 p.m. ET (after the day's session)
Earlier Nasdaq commentary described an 8:00 p.m. Sunday to 8:00 p.m. Friday framework, but the latest description aligns the Sunday start with the 8–9 p.m. technical pause.
Additionally, in Nasdaq's proposed night session, trades executed between 9:00 p.m. and 12:00 a.m. ET count as next-day trades.
That matters for reporting, some broker statements, and how traders reconcile fills against daily charts.
| Feature | Today (typical) | Proposed Nasdaq 5×23 |
|---|---|---|
| Core cash session | 9:30 a.m.–4:00 p.m. ET | 9:30 a.m.–4:00 p.m. ET (unchanged) |
| Extended trading | 4:00 a.m.–9:30 a.m., 4:00 p.m.–8:00 p.m. ET | 4:00 a.m.–8:00 p.m. day session + 9:00 p.m.–4:00 a.m. night session |
| Overnight exchange trading | Limited / mostly off-exchange venues | On-exchange night session (pending SEC) |
| Weekly window | Monday–Friday | Sunday 9:00 p.m.–Friday 8:00 p.m. ET |
| Daily halt | None beyond regular halts | 1-hour technical pause each day |
Retail brokers and some alternative trading systems already offer forms of overnight trading. However, the liquidity is fragmented, and the price discovery can be uneven.
Nasdaq's own commentary describes the current environment as a patchwork where overnight trading exists, but major exchanges bring scale, surveillance, and consolidated market structure.
Nasdaq is not acting in isolation.
NYSE Arca has pursued extended-hours expansions (approved for 22 hours in earlier steps) as part of the industry's move toward longer trading days.
Cboe and other venues are exploring similar models, and the SEC is increasingly focused on extended-hours trading as a regulatory theme heading into 2026.
In other terms, Nasdaq's 23/5 proposal signifies a wider movement in the US market, rather than a singular trial.
There is also a competitive logic.
If global traders want US equities exposure during Asia hours, the exchange that provides the deepest, cleanest overnight market is likely to win:
Higher trading volumes
More market data value
More relevance to issuers considering where to list
That is the institutional incentive behind the marketing language.
The benefit is obvious: you can respond to macro headlines, geopolitics, and earnings news without waiting for the New York open.
The risk is equally obvious: liquidity tends to be thinner overnight, which can mean:
Wider bid–ask spreads
More slippage on market orders
Sharper jumps on small prints
Market makers explicitly highlight concerns from large banks about liquidity and volatility during non-traditional hours.
A critical question is how smoothly ETFs and single stocks will trade overnight when:
The underlying constituents might not be trading actively
Index futures might be more liquid than cash equities
Corporate news can hit at any time
Nasdaq's stated goal is that exchange-led overnight trading improves transparency and price formation compared with purely off-exchange solutions.
For brokers, the hardest operational issue is not simply "turning trading on".
It is managing best execution when liquidity is split across:
Nasdaq's overnight session
Other exchanges' overnight sessions
Alternative trading systems
Internalisers and wholesalers
It is exactly why regulators and industry bodies are treating extended-hours trading as a serious policy and market-structure topic for 2026.
For Asia-Pacific investors, this is the key attraction. A Sunday 9:00 p.m. ET open is Monday morning in Asia, which means international investors can trade Nasdaq-listed stocks while they are awake, not while they are asleep.
If you hold concentrated tech exposure, you already carry overnight gap risk. A longer market window gives you more ways to hedge or reduce exposure after hours, especially if your broker routes to the exchange session.
Volatility is not automatically bad for traders. It's risky for poorly executed market orders, but advantageous for disciplined traders using limit orders, defined risk, and liquid instruments.
The core risk is that overnight trading looks active in headlines but behaves like a thin market in practice.
Thinner liquidity means small orders can move prices further than traders expect, especially in single stocks outside the mega-cap leaders. This concern results from large banks and liquidity providers.
A near-continuous market needs resilient consolidated data feeds and clean opening/closing processes.
Nasdaq itself has written that getting to 24-hour trading requires alignment across exchanges, regulators, and "critical market infrastructure".
Extended hours can invite more aggressive games:
Spoofing attempts in thin books
Marking the close or "marking the open" behaviour shifting into new time windows
Greater reliance on surveillance technology
For regulators, that is not a theoretical issue. It is one of the reasons extended-hours trading is now on the policy radar.
Nasdaq is targeting the second half of 2026, subject to SEC approval and readiness of market infrastructure such as DTCC clearing and consolidated data systems.
No. The model is "near 24/5", not 24/7. The proposed week runs from Sunday evening to Friday evening in US time.
Nasdaq and industry groups describe the pause as necessary for maintenance, testing, and post-trade processes. It is also a practical window for clearing and operational resets.
In most cases, yes. Extended sessions generally have lower liquidity, and concerns around thinner liquidity and higher volatility are central to the debate.
Settlement in US markets moved to T+1 in May 2024. Longer trading hours do not automatically change settlement rules, but they do increase the need for longer clearing and post-trade processing windows.
In conclusion, Nasdaq's 23/5 plan aims to bring overnight US equity trading out of the shadows into a more standardised, regulated framework.
If SIP, DTCC clearing, trade reporting, and investor protections expand in tandem, 23-hour trading could enhance global access and curb reliance on fragmented off-exchange sessions.
However, if you treat it like a casino that never closes, it will behave exactly like one.
Disclaimer: This material is for general information purposes only and is not intended as (and should not be considered to be) financial, investment or other advice on which reliance should be placed. No opinion given in the material constitutes a recommendation by EBC or the author that any particular investment, security, transaction or investment strategy is suitable for any specific person.
