US Stock Trading Goes 23 Hours a Day: What Is Approved, What Is Scheduled, and What It Means for Small-Cap Day Traders

The short version

What has been approved

Nasdaq: a Day Session and a Night Session

The SEC approved Nasdaq’s proposal to trade NMS stocks 23 hours a day, five days a week, on April 10, 2026 (Release No. 34-105199, SR-NASDAQ-2025-109). Nasdaq filed it on December 29, 2025. Under the approved rules:

• Premarket, regular and post-market hours become one Day Session (4:00 a.m.–8:00 p.m. ET), with the Opening and Closing Crosses unchanged.
• A new Night Session runs 9:00 p.m.–4:00 a.m. ET, Sunday through Thursday nights. All NMS stocks are eligible.
• Trading pauses 8:00–9:00 p.m. (Monday–Thursday) for maintenance and next-day corporate actions.
• Limit orders only overnight; unpriced and pegged orders are rejected. Limit Order Protection and clearly erroneous rules apply.
• Nasdaq cancels all open orders at 8:00 p.m. and at 4:00 a.m., so Night Session orders do not carry into premarket.

The approval is conditional: the Night Session cannot open until the SIPs can carry overnight quotes and trades as they do in regular hours, and Nasdaq has filed a further rule change confirming that. Later filings describe the launch as “on or about December 6, 2026” (34-106233, 34-106319). A September 30, 2026 filing (34-106548) requires clearing firms to confirm in writing which correspondents’ Night Session trades they will clear, so each retail broker’s clearing arrangement must opt in.

NYSE Arca: the first approval, later reshaped

NYSE Arca won the first exchange approval for longer hours on February 11, 2025 (34-102400), originally 1:30 a.m.–11:30 p.m. ET. A May 2026 immediately effective filing (34-105532) reshaped this to match the industry: an Overnight Trading Session from 9:00 p.m. (Sunday–Thursday) that opens with continuous trading rather than an auction, an Early session from 4:00 a.m., Core, and a Late session ending 8:00 p.m. Market and pegged orders are excluded overnight. The same SIP-readiness and further-filing conditions apply.

Cboe EDGX and MEMX

The SEC approved Cboe EDGX’s 23/5 proposal on May 29, 2026 (34-105587). The EDGX order spells out two conventions that other venues are expected to share:

• A trading day runs from 9:00 p.m. ET on one calendar day to 8:00 p.m. ET on the next.
• Trades at or after 9:00 p.m. get the following calendar day’s trade date.

On EDGX, a Day order entered for the overnight session can stay live through the Pre-Opening Session and Regular Trading Hours. Nasdaq handles this differently, as noted above.

MEMX filed its 23/5 rules on September 9, 2026 as an immediately effective rule change (34-106310, SR-MEMX-2026-28), targeting December 6, 2026. That is a filing that took effect on its own terms, not an SEC approval order.

24X National Exchange

The SEC approved 24X’s registration as a national securities exchange on November 27, 2024 (Release No. 34-101777), and 24X announced October 14, 2025 as the launch date for its first-stage 4:00 a.m.–8:00 p.m. trading. Its 9:00 p.m.–4:00 a.m. session is also tied to SIP readiness. An August 7, 2026 contingency order (34-106061) lets 24X open overnight from January 24, 2027, under conditions such as publishing its own real-time feed, only if the SIPs miss December 6. That relief ends when the SIPs go live, or by July 2, 2027 at the latest.

The plumbing: SIP, LULD, clearing and trade reporting

• SIP hours. The SEC approved the UTP Plan amendment on June 26, 2026 (34-105780), and the SIPs announced on July 7, 2026 that both the CTA/CQ and UTP amendments were approved: 9:00 p.m. Sunday to 8:00 p.m. Friday ET, with a one-hour pause at 8:00 p.m. Monday–Thursday, implementation December 6, 2026. Weekend tests run October 2, 16, 30, November 6, 20 and December 4.
• LULD overnight bands. Amendment No. 27 approved August 5, 2026 (34-106042); details below.
• Clearing. NSCC 24x5 clearing has been live since June 29, 2026.
• Trade reporting. FINRA TRFs open at 4:00 a.m. today (since March 30, 2026, RN 26-07) and move to 9:00 p.m. Sunday–8:00 p.m. Friday from December 6, 2026.
• Circuit breakers. September 2026 immediately effective filings keep the rule that after a Level 3 halt, trading resumes no earlier than 4:00 a.m. next day, with no overnight session that evening.

What is scheduled, and what is still open

Scheduled: the December 6, 2026 start for the SIPs, TRFs, LULD overnight bands and exchange overnight sessions. Every exchange rule ties the actual start to SIP readiness plus a separate “readiness” rule filing. As of October 5, 2026, we had not found those readiness filings for Nasdaq, NYSE Arca or Cboe EDGX on the SEC’s site. Until they appear, treat December 6 as the target date, not a confirmed one.

Open or proposed:

• Best execution overnight. FINRA Regulatory Notice 26-15 (July 24, 2026) asks how best-execution obligations should work when liquidity and quotes look very different from regular hours. Comments closed September 25, 2026. Guidance has not been issued yet.
• LULD Phase 2. The plan participants say they will study overnight trading data and later propose permanent overnight protections to replace Phase 1.
• Reg SHO Rule 201 overnight mechanics. See the short-sale section below.
• 24/7 trading. No exchange rule filing for weekend trading of NMS stocks appeared in our search.

What changes for small-cap day traders

1. Liquidity: more hours, not necessarily more shares

More hours do not create more buyers and sellers. The approval orders themselves describe extended hours as having lower liquidity, wider spreads and more volatility, and exchanges added overnight risk disclosures on top of FINRA Rule 2265. For thin small caps, expect sparse overnight books where small orders can move price sharply.

2. Gaps get spread across the night

Price discovery that today shows up as a 4:00 a.m. or 9:30 a.m. gap will be able to happen overnight once the session opens, though news released during the 8:00–9:00 p.m. pause still first trades at 9:00 p.m. “Gap” numbers will depend more on the reference price:

• the official closing price from the listing exchange (4:00 p.m.),
• the last after-hours price (up to 8:00 p.m.),
• or the last overnight price (up to 4:00 a.m.).

3. Halts and LULD: what the overnight bands do, and don’t do

Under LULD Amendment No. 27 (Phase 1):

• Overnight Price Bands apply only from 9:00 p.m. to 4:00 a.m. ET. They are static, set once before 9:00 p.m. and not recalculated during the session.
• They are built from two reference prices: the official closing price and the consolidated last round-lot sale as of 7:45 p.m. ET. The lower band is 20% below the lower of the two. The upper band is 20% above the higher of the two.
• Minimum widths: $1.00 from the reference price for stocks that closed under $1.00, and $3.00 for stocks at $1.00 or more. Leveraged ETPs get proportionally wider bands.
• Reaching a band does not trigger an automatic trading pause. Trading centers must block trades and quotes outside the bands. The primary listing exchange may call a regulatory halt, for example when orders keep arriving outside the bands. A stock halted during the overnight window does not reopen during that window (before 4:00 a.m.).
• No LULD bands in premarket (4:00–9:30 a.m.) or after hours (4:00–8:00 p.m.). That doesn’t change. The bands stop at 4:00 a.m. on purpose, so earnings and other premarket news can move prices freely. Classic premarket small-cap spikes are still not covered by LULD.

On halts more generally: when a primary listing market halts a stock, Nasdaq’s rules halt it in the Night Session too until the primary market resumes it. According to the UTP SIP FAQ, regulatory halts still open at the end of a session carry into the next session. Non-regulatory halts do not. Some corporate actions, including splits, dividends, mergers and symbol changes, may require halts that run past the 8:00–9:00 p.m. pause (Nasdaq order).

4. Order types and time-in-force

• Limit-price orders only. Nasdaq’s and NYSE Arca’s rules exclude market and pegged orders overnight, and industry summaries describe every planned exchange overnight session the same way.
• Time-in-force differs by venue. Nasdaq cancels everything at 8:00 p.m. and 4:00 a.m. An SDAY order meant for the Night Session expires at 4:00 a.m. On EDGX, a Day order can stay live from 9:00 p.m. through regular hours. Your broker decides how its own TIF options (for example “overnight”, “extended” or “GTC + extended”) map to each venue. Check before you assume an overnight order is still working at 4:00 a.m.
• Price protection. Nasdaq’s Limit Order Protection and NYSE Arca’s Limit Order Price Protection apply overnight, so orders priced too far from the market may be rejected.

5. Broker support will arrive in stages

Retail access runs through member brokers, and each broker decides whether to route overnight, which symbols to allow, which TIFs to offer and how margin works across a 23-hour day. Nasdaq’s clearing-affirmation rule adds a clearing-side step. Overnight trading itself isn’t new: FINRA notes rising retail participation in overnight hours as alternative trading systems (ATSs) have offered trading during the overnight session (Regulatory Notice 26-15). Whether and when your broker routes to the new exchange sessions is up to its own announcement.

6. Short selling: Reg SHO Rule 201 (SSR) timing

Rule 201 (the short-sale circuit breaker) applies when a stock falls 10% or more from the prior day’s closing price. Once triggered, it covers the rest of that day and the following day. Under 23/5, the “day” boundary moves:

• The UTP SIP FAQ says SSR states advance at the start of each new session, at about 8:55 p.m. ET. “Active” becomes “Continued”, and “Continued” becomes “Deactivated”. An SSR triggered during Monday’s regular session therefore stays in effect through the Tuesday trading day, which starts at 9:00 p.m. Monday. It does not end at midnight.
• A decline during the overnight session does not trigger SSR under current SEC staff guidance. The SEC’s Rule 201 FAQ says the circuit breaker can be triggered only by trades reported during regular trading hours (9:30 a.m.–4:00 p.m. ET). Once triggered, the price test applies whenever a national best bid is being disseminated under an NMS plan, which will include the overnight session (as of October 6, 2026). The SEC has not issued guidance written specifically for the new overnight session, so ask your broker how it flags SSR overnight. Short availability (locates) overnight is also a broker decision.

7. Settlement and trade dates

US equities settle T+1. A trade at 10:00 p.m. Monday belongs to Tuesday’s trade date (EDGX rule) and settles one business day after that. Expect statements and cost-basis records to show the later trade date.

What this means for data and scanners

If you build or use scanners:

• The trading day starts the evening before. A “Tuesday” bar may include trades from 9:00 p.m. Monday. Daily OHLCV, “premarket volume since 4:00 a.m.” and “% change from prior close” all need an explicit session definition.
• Overnight trades count toward volume but don’t update the official last sale. The UTP SIP FAQ says trades outside 9:30 a.m.–4:00 p.m. keep their extended-hours sale condition and are not last-sale eligible. They still count toward consolidated volume. Consolidated high, low and last can therefore differ from “all-session” high, low and last.
• Today, overnight off-exchange prints aren’t on the tape in real time. TRFs open at 4:00 a.m. ET, and both SIPs carry trading from 4:00 a.m.: the UTP SIP publishes its start of day at about 3:58 a.m. and opens to all participant messages at 4:00 a.m. (UTP SIP FAQ); the CTA SIP starts its system day at 1:30 a.m., with its trading session from 4:00 a.m. (CTA FAQ). From December 6, the TRFs and both SIPs run from 9:00 p.m., so overnight trades should appear in consolidated data as they happen.
• New status messages. The UTP SIP added overnight LULD band indicator values “G” and “H”. Halt and SSR states are republished around 8:55 p.m. Corporate actions and adjusted reference prices are applied before the next session.
• Holidays. No session runs the evening before a market holiday. The next session starts at 9:00 p.m. on the holiday evening, or on Sunday if the holiday falls on a Friday (UTP SIP FAQ).

Label every price with its session and time (“last overnight print, 3:12 a.m. ET” vs “official close, 4:00 p.m. ET”), and don’t weigh a thin overnight print like a regular-hours close.

What to watch between now and December 6

1. Exchange readiness filings confirming SIP readiness (Nasdaq, NYSE Arca, Cboe EDGX, 24X, MEMX).
2. SIP test results through the December 4 rehearsal, and any vendor alert that changes the date.
3. Broker announcements on routing, symbol lists, TIF options and margin treatment overnight.
4. FINRA’s response to the best-execution comments (RN 26-15).
5. Primary-exchange halt policies for corporate actions and overnight news.

FAQ

Is the US stock market going to trade 24 hours a day? Not quite. The approved model is about 23 hours a day, five days a week. Trading runs from 9:00 p.m. ET Sunday to 8:00 p.m. ET Friday, with a one-hour pause from 8:00 to 9:00 p.m. Monday through Thursday. As of October 5, 2026, the target start is December 6, 2026, and there are no weekend sessions for NMS stocks.

Which exchanges have SEC approval for overnight trading? Nasdaq (April 10, 2026), Cboe EDGX (May 29, 2026), NYSE Arca (February 11, 2025) and 24X (registered November 2024). MEMX filed immediately effective rules on September 9, 2026. All require SIP readiness plus a readiness filing before overnight trading starts.

Is December 6, 2026 confirmed? It is the date in the SIP, LULD and TRF changes. Exchange launches still need readiness filings, not found as of October 5, 2026. If the SIPs slip, 24X may start overnight on January 24, 2027.

Will LULD halts protect me overnight? Partly. From 9:00 p.m. to 4:00 a.m., static 20% bands block trades outside them, without automatic pauses; the listing exchange can still halt. There are still no LULD bands 4:00–9:30 a.m. or 4:00–8:00 p.m.

Can I use market orders overnight? No. Nasdaq and NYSE Arca exclude market and pegged orders overnight, and the planned exchange overnight sessions are described as limit-price only.

Does my order placed at 10 p.m. still work at the 9:30 a.m. open? It depends on the venue and your broker. Nasdaq cancels Night Session orders at 4:00 a.m. Cboe EDGX lets Day orders entered overnight stay live through regular hours. Check your broker’s time-in-force options.

How does SSR (Rule 201) work with a 9 p.m. start? SSR states advance at the start of the new trading day (about 8:55 p.m. ET), so a restriction triggered during regular hours covers the following overnight session too. A 10% decline during the overnight session itself does not trigger SSR: under the SEC’s Rule 201 FAQ, only trades reported during regular trading hours count toward the trigger (as of October 6, 2026).

Will overnight trades change a stock’s official high, low and close? Overnight trades count toward consolidated volume but are not last-sale eligible, per the UTP SIP FAQ. The official close is still set by the listing exchange at 4:00 p.m.

Related reading

To keep checking related concepts, read Premarket and after-hours sessions, LULD price bands and pauses, Trading halts, Market, limit and stop orders, SSR and Rule 201, Gap up and gap down, FINRA’s intraday margin rule; the FennEdge dilution course; and the trading glossary.

Sources

• SEC Release No. 34-105199 (Apr. 10, 2026) — Nasdaq 23/5 approval order, SR-NASDAQ-2025-109
• SEC Release No. 34-102400 (Feb. 11, 2025) — NYSE Arca extended hours approval, SR-NYSEARCA-2024-89
• SEC Release No. 34-105532 (May 21, 2026) — NYSE Arca Overnight Trading Session filing, SR-NYSEARCA-2026-53
• SEC Release No. 34-105587 (May 29, 2026) — Cboe EDGX 23/5 approval order, SR-CboeEDGX-2026-019
• SEC Release No. 34-106310 (Sept. 9, 2026) — MEMX 23/5 filing, SR-MEMX-2026-28
• SEC Release No. 34-101777 (Nov. 27, 2024) — Order granting 24X National Exchange registration as a national securities exchange, File No. 10-242
• SEC Release No. 34-106061 (Aug. 7, 2026) — 24X temporary conditional exemptive order
• SEC Release No. 34-105780 (June 26, 2026) — UTP Plan 55th Amendment (SIP hours)
• SEC Release No. 34-106042 (Aug. 5, 2026) — LULD Plan Amendment No. 27 (overnight price bands)
• SEC Release No. 34-106548 (Sept. 30, 2026) — Nasdaq Night Session clearing affirmation, SR-NASDAQ-2026-084
• SEC Release No. 34-106233 (Aug. 28, 2026) — Nasdaq Night Session port fees (launch ’on or about December 6, 2026’)
• SEC Release No. 34-106319 (Sept. 10, 2026) — Nasdaq Night Session port fees, SR-NASDAQ-2026-073
• SEC Division of Trading and Markets — Responses to Frequently Asked Questions Concerning Rule 201 of Regulation SHO
• UTP SIP Extended Trading Hours FAQ, Version 1 (June 2026)
• CTA Extended Trading Hours — Frequently Asked Questions, Version 1.2 (Sept. 29, 2026)
• UTP Vendor Alert #2026-24 (Aug. 12, 2026)
• SIPs Receive SEC Approval for Extended Trading Hours Initiative (press release, July 7, 2026)
• DTCC — NSCC Launches 24x5 Clearing for U.S. Equities (June 29, 2026)
• FINRA — Extension of TRF Operating Hours (technical notice, May 22, 2026)
• FINRA Regulatory Notice 26-07 (Mar. 9, 2026)
• FINRA Regulatory Notice 26-15 (July 24, 2026) — best execution guidance request
• Federal Register (Sept. 18, 2026) — NYSE Arca Rule 7.12-E, Level 3 MWCB resumption under 23/5
• 24X — Launch date for first stage moved to October 14, 2025 (press release)
• WilmerHale — 23x5 Trading Comes to US Exchanges (Sept. 29, 2026) (secondary; used only where noted)