# What 23-hour stock trading changes in your market data

The US consolidated tape is scheduled to run 23 hours a day from 6 December 2026. What moves in trade dates, daily bars, volume, flags and calendars.

*https://stockmarketstack.com/guides/overnight-trading-data · background to Desktop Trading Platforms & Order Flow*

**Answer:** The two US consolidated tapes are scheduled to run from 9 p.m. Sunday to 8 p.m. Friday Eastern from 6 December 2026, with a one-hour pause each evening. A trade date then starts at 8 p.m. the evening before. Overnight trades carry the same T condition as pre-market and after-hours trades. They count toward consolidated volume but never set the consolidated high, low or last. The official open and close remain the 9:30 and 4:00 auctions.

The US consolidated tape has always gone dark in the evening. Trades and quotes from every exchange
flow through two securities information processors, the SIPs, which have operated from early
morning to 8 p.m. Eastern. On 26 June 2026 the SEC approved amendments to both plans to run
them from 9 p.m. Sunday to 8 p.m. Friday, with a one-hour pause each weeknight. The plans have
scheduled the switch for Sunday 6 December 2026.

For someone who reads charts or pulls bars from an API, the change matters less for the overnight
prices than for what it does to things that looked fixed: when a trading day starts, which trades
a daily bar contains, and what a flag on a trade tells you. Most of that is written down in the
plan documents. What your own tools will do with it mostly is not yet.

## How it works

Trades come from two kinds of venue, travel through two pipes, and reach you through a vendor.

**Exchanges** report to the SIP for the stock's tape: the CTA plan for NYSE-, NYSE American- and
regional-listed stocks, the UTP plan for Nasdaq-listed stocks. Each exchange decides for itself
whether to trade overnight, and each needs SEC approval of its own rules to do so. Nasdaq's
approval is [Release 34-105199](https://www.sec.gov/files/rules/sro/nasdaq/2026/34-105199.pdf) of
10 April 2026 and Cboe EDGX's is
[Release 34-105587](https://www.sec.gov/files/rules/sro/cboeedgx/2026/34-105587.pdf) of 29 May
2026. Within each group the overnight session is narrower than the brand suggests. Cboe's FAQ says
BZX, BYX and EDGA will not adopt one, so only EDGX trades overnight. NYSE's FAQ for NYSE Arca says
the other NYSE Group equities exchanges keep their current hours. Nasdaq's FAQ says Nasdaq Texas
and PSX keep theirs.

**Off-exchange trades**, from alternative trading systems and wholesalers, are reported to a FINRA
trade reporting facility, which passes them to the same SIPs.
[FINRA's filing of 15 July 2026](https://www.sec.gov/files/rules/sro/finra/2026/34-105922.pdf)
describes the rule in force before the change. The facilities run from 4 a.m. to 8 p.m. A trade
executed between 8 p.m. and midnight is reported by 4:15 a.m. on the next business day, marked "as/of". A trade
between midnight and 4 a.m. is reported by 4:15 a.m. A trade on a weekend or holiday can be
suppressed from public dissemination altogether. The filing extends the facilities to the SIPs'
new hours and requires a report within 10 seconds of execution. FINRA ties its implementation date
to the SIPs'.

**Vendors** take the SIP feeds, an exchange's own feed, or both, and build the bars, snapshots and
charts you actually see. Nothing in the plan documents tells them how to build a daily bar.

## The trading day starts the evening before

The [CTA plan's FAQ](https://www.ctaplan.com/publicdocs/ctaplan/CTA_Extended_Trading_Hours_FAQ.pdf),
version 1.2 of 29 September 2026, puts it in one sentence: "The entire 9:00 PM – 8:00 PM window is
one trading day." Trades and quotes reported between 9 p.m. and midnight "are counted under the
next calendar date for all statistical calculations (e.g., volume and revenue calculations)."
Nasdaq, NYSE Arca and Cboe EDGX each state the same split in their own FAQs. A trade at 11:30 p.m.
on Monday is a Tuesday trade, and one at 12:30 a.m. on Tuesday is also a Tuesday trade. NYSE
Arca's FAQ shows the consequence for settlement: an overnight trade at 10 p.m. on 23 November 2026
has a trade date and clearing date of 24 November and settles on the 25th.

Holidays move with it. There is no session on the evening before a US market holiday, and the next
session opens at 9 p.m. on the holiday itself if the following day is a business day. The CTA FAQ's
own example is Christmas 2026, which falls on a Friday. There is no session on Thursday night or
during Friday's regular hours, none on Friday night either, and trading resumes at 9 p.m. on
Sunday 27 December.

The SIPs' published day also moves. In the CTA schedule, start of day goes from 1:30 a.m. to 8:55
p.m. the evening before. Symbol reference data, halts carried over from the previous session and short-sale restrictions are all published at 8:55 p.m.
Late-reported trades from the session that just ended, and cancellations or corrections of its
trades, can be submitted from 9 p.m. in the next one. A daily file built at midnight can still
change.

## What the tape marks, and what it leaves alone

The flag is the part most likely to be misread. The CTA FAQ says trades outside regular hours "will
continue to use the 'T' sale condition and are not Last Sale eligible. This applies to both the
Extended Early Hours (9:00 PM – 9:30 AM) and any trades after the 4:00 PM close." NYSE Arca and Cboe
EDGX say the same about their own overnight trades. The UTP FAQ says its existing designated
condition continues. So **one condition covers overnight, pre-market and after-hours**. Nothing on
the trade distinguishes 11 p.m. from 7 a.m. except the timestamp.

What T does is set out in the sale condition table of the
[CTS output specification](https://www.ctaplan.com/publicdocs/ctaplan/CTS_Pillar_Output_Specification_ETH.pdf),
version 2.12b of 1 July 2026: a T trade updates volume, and updates neither the consolidated last,
high or low nor the participant's open, last, high or low. The UTP specification's matrix gives T
the same row. In practice:

- **Consolidated volume for a trade date includes the overnight trades** from 9 p.m. the evening
  before. The CTA and UTP FAQs both say so.
- **The consolidated high and low do not.** An overnight spike will not appear in a high or low
  built from the SIP's consolidated fields. It will appear in a bar a vendor builds by aggregating
  every trade itself.
- **The official open and close do not change.** Nasdaq's FAQ says the 9:30 a.m. to 4:00 p.m.
  session, "marked by the Opening and Closing Crosses, will continue to set the prices". NYSE Arca
  will keep publishing its official closing price after the 4 p.m. auction with sale condition M.
  Arca's overnight session opens at 9 p.m. with no auction at all. Its first auction of the trade
  date is still the 4 a.m. early open.

Overnight price limits are new and narrow. From 9 p.m. to 4 a.m. static bands apply, provided by
the listing exchanges and based on a percentage of the 4 p.m. official close and a consolidated
round-lot sale in the evening. NYSE's FAQ puts them at 20%. From 4 a.m. to 9:30 a.m. there are no
bands, as before. The exchanges also restrict what can trade: Nasdaq accepts only limit orders from
9 p.m. to 4 a.m., with no market or peg orders and no orders for the crosses, and cancels anything
still resting at 4 a.m.

## If the date slips, and what runs before it

The 6 December date is conditional. The CTA FAQ makes it "dependent on Listing Exchange readiness
and regulatory approvals". The SEC planned for a delay in its
[order for 24X National Exchange](https://www.sec.gov/files/rules/exorders/2026/34-106061.pdf) of
7 August 2026. If the plans cannot meet 6 December, 24X may run its overnight session from 24
January 2027 without the SIPs, publishing the trades on its own proprietary feed instead. The
relief ends when the SIP amendments are implemented or on 2 July 2027, whichever comes first. In
that case overnight prices would exist only on venue feeds, and a tool on the consolidated tape
would see none of them.

From 8 November to 5 December 2026 the CTA side runs a pre-launch: the overnight schedule in
production, with trades and quotes for test symbols only. The
[UTP FAQ](https://www.utpplan.com/DOC/Nasdaq%20UTP%20SIP%20Extended%20Trading%20Hours%20FAQ%20Finalized%20Version%201.2.pdf)
says there will be no UTP pre-launch. Some nights in November will carry test-symbol messages on
one tape and nothing on the other.

## Corporate actions take effect at 9 p.m.

A split or a dividend used to take effect in the hours between the evening close and the morning
open, when nothing traded. Under 23-hour trading something may be trading. On the CTA tape, listing
exchanges send corporate actions and adjusted closing prices in a file due by 8 p.m., and the SIP
publishes them in the start-of-day reference data at 8:55 p.m.
[Nasdaq's FAQ](https://www.nasdaq.com/docs/nasdaq-global-trading-hours-faqs) says, pending SEC
approval, that certain corporate actions and dividends "will be effective when trading commences
at 9 p.m." Others will be halted from before 9 p.m. on the evening before the effective date until
8 a.m. on that date, under halt code M1. The list includes forward and reverse splits, symbol and
CUSIP changes, spin-offs, mergers and dividends of 25% or more of the official close.

Under Nasdaq's proposal, the first trade on an ex-dividend date can print at 9 p.m. the evening
before, against an adjusted reference price. Nasdaq's FAQ also warns that between its overnight session and the
session that starts at 4 a.m., "reference data, including stock locate code assignments, can
change". Code that caches a locate code or a symbol mapping for a whole calendar day will be wrong
for part of it.

## What each kind of tool will and will not show

**Data APIs.** Whether a daily bar is keyed by trade date or by calendar date is now a real
question. Bars keyed by trade date put a Sunday 9:30 p.m. trade in Monday's bar. Bars cut at
midnight in New York put it in Sunday's, a day with no regular session. Bars cut at midnight UTC
happen to put 9 p.m. to midnight Eastern into the next day, but in winter they move the last hour
of the late session there too. [Alpaca](https://stockmarketstack.com/tools/alpaca-market-data)'s market data FAQ says a trade's
timestamp is truncated "to the day (in New York) for daily bars", a rule that would put a Sunday
night trade in a Sunday bar unless it changes. Massive's announcement of 26 August 2026 says
product details "will be shared in the coming months". Venue feeds for overnight trading already
exist. Alpaca documents a Blue Ocean ATS feed and a cheaper
derived "overnight" feed whose trades, its docs say, "are 15 minutes delayed and adjusted to fit the
bid-ask spread". Both are one venue's activity, not the tape.

**Charting platforms.** [TradingView](https://stockmarketstack.com/tools/tradingview)'s support page describes a 24h session
for "BOATS-supported US stocks", which merges regular, extended and overnight activity on intraday
charts only. That is the Blue Ocean ATS, one venue. After the SIPs extend their hours, an overnight
candle can come from the consolidated tape or from a single venue feed, and the two will not agree.
Cboe's FAQ lists Cboe One among the feeds that will carry EDGX's overnight trades. That matters
because TradingView's free US real-time data is the Cboe One feed, according to its data-coverage
page. Daily candles are a separate matter. Whether
a platform's daily bar includes overnight trading is not stated on any page cited here. See
[why two charts show a different daily candle](https://stockmarketstack.com/guides/why-two-charts-show-different-candles).

**Desktop trading platforms.** Platforms here do not make the data. They display the feed you
connect. [Sierra Chart](https://stockmarketstack.com/tools/sierra-chart) sells the US equities consolidated tape as an add-on.
A platform fed from the tape can receive overnight trades once the SIPs carry them, if its data
service passes them through. Session templates are the thing to check. A chart session defined as 4:00 a.m. to 8:00 p.m. will either
drop the trades from 9 p.m. or fold them into the wrong day.

**Calendars and trackers.** A calendar that models only the regular session still names the right
trade date, but it cannot tell you when that date began.
[exchange_calendars](https://stockmarketstack.com/tools/exchange-calendars) treats everything outside regular trading as
closed. [pandas_market_calendars](https://stockmarketstack.com/tools/pandas-market-calendars) adds pre- and post-market times
only when asked and only where a calendar defines them. Neither card records a 9 p.m. start.
Portfolio trackers that mark positions to "last price" will start moving in the evening if their
feed carries overnight trades. Those that mark to the official close will not move until 4 p.m.

## What you can do about it

**Decide which day an overnight trade belongs to, and write it down.** If you store trades or
bars, keep two fields: the timestamp in UTC and the trade date as the plans define it, with 8 p.m.
Eastern as the boundary. Every daily aggregate you compute should group by the second. Computing
the trade date from the timestamp later, without a calendar, will put holiday-evening trades in
the wrong place.

**Do not use the T flag to mean "pre-market".** It means "outside 9:30 to 4:00", from 9 p.m. the
night before to 8 p.m. If you split sessions, split them by time: overnight before 4 a.m., early
from 4 a.m. to 9:30, regular, and late after 4 p.m.

**Ask your data vendor four questions before 6 December.** Are daily bars keyed by trade date or
by calendar date, and in which time zone? Does daily volume include overnight trades? Are daily
highs and lows built from every trade or from regular-session-eligible trades only? Does the
overnight data come from the SIP or from a single venue such as an ATS? Take the answer from their
documentation, with its date, not from a support chat.

**Re-check session templates and scheduled jobs.** A job that builds yesterday's bars at 1 a.m.,
a chart session that starts at 4 a.m. and a cache that refreshes symbol data once a calendar day
were all built on the old schedule. Their failure mode is quiet: a missing hour or a doubled one.
The how-tos on [backfilling minute bars](https://stockmarketstack.com/how-to/backfill-minute-bars) and
[getting an exchange calendar as data](https://stockmarketstack.com/how-to/get-an-exchange-trading-calendar-as-data) describe
the pieces that need the new boundary.

**Check the first weeks against a second source.** The plans' own FAQs leave room for the date to
move, and the fallback runs on a single venue's feed. Compare a few symbols' overnight volume and
trade dates across two sources in the first week, before you trust a backtest or a report that
spans the change.

## Tools this bears on

- [TradingView](https://stockmarketstack.com/tools/tradingview.md) — Charting across 50-plus markets, with Pine Script, server-side alerts and broker trading.
- [Alpaca Market Data](https://stockmarketstack.com/tools/alpaca-market-data.md) — Free IEX data forever, full SIP and OPRA for a flat $99 a month.
- [Sierra Chart](https://stockmarketstack.com/tools/sierra-chart.md) — Windows-native charts, order flow and DOM trading, priced as packages plus exchange fees.
- [pandas_market_calendars](https://stockmarketstack.com/tools/pandas-market-calendars.md) — Exchange schedules as pandas DataFrames, with CME, CBOE options and bond-market calendars.

## FAQ

### When does 24-hour stock trading start in the US?

The consolidated tapes are scheduled to start extended operation on Sunday 6 December 2026, running from 9 p.m. Sunday to 8 p.m. Friday Eastern with a pause from 8 to 9 p.m. each weeknight. That is 23 hours a day, not 24. The CTA plan's own FAQ makes the date dependent on listing-exchange readiness and regulatory approvals, and each exchange needs SEC approval for its own overnight session.

### Which trade date does an overnight stock trade belong to?

The next one, if it happens before midnight. Trades between 9 p.m. and midnight carry the following calendar day's trade date, and trades from midnight to 8 p.m. carry the same day's date. A Sunday 9:30 p.m. trade is a Monday trade, and the CTA plan counts it under Monday for volume and every other statistic.

### Will overnight trades change a stock's official closing price?

No. The official open and close are still set by the listing exchange's auctions at 9:30 a.m. and 4:00 p.m. Overnight, pre-market and after-hours trades carry the T sale condition, which in both SIP specifications updates volume and nothing else on the consolidated record. They do not move the consolidated last sale, high or low.

### Can I tell an overnight trade from a pre-market trade in the data?

Not from the sale condition. The CTA FAQ applies the same T condition to everything from 9 p.m. to 9:30 a.m. and after the 4 p.m. close, so overnight, pre-market and after-hours prints look identical except for their timestamps. The session has to be worked out from the time of the trade and its trade date.

### Why does my data provider already show overnight trades?

Because some alternative trading systems already run evening sessions, and vendors buy their data directly. Until the extended hours start, those trades are reported to FINRA after the fact, not in real time. Trades executed between 8 p.m. and midnight are reported by 4:15 a.m. on the next business day, marked as of their trade date. So a vendor's overnight feed is one venue's data, not the consolidated tape.

## Sources

1. [Order Approving the Fortieth Substantive Amendment to the CTA Plan and Thirty-First Substantive Amendment to the CQ Plan, Release No. 34-105779](https://www.sec.gov/files/rules/sro/nms/2026/34-105779.pdf) — U.S. Securities and Exchange Commission, 2026-06-26
2. [Order Approving the Fifty-Fifth Amendment to the UTP Plan, Release No. 34-105780](https://www.sec.gov/files/rules/sro/nms/2026/34-105780.pdf) — U.S. Securities and Exchange Commission, 2026-06-26
3. [CTA Extended Trading Hours — Frequently Asked Questions, version 1.2](https://www.ctaplan.com/publicdocs/ctaplan/CTA_Extended_Trading_Hours_FAQ.pdf) — Consolidated Tape Association / Securities Industry Automation Corporation, 2026-09-29
4. [Nasdaq UTP SIP Extended Trading Hours Implementation FAQs, version 1.2 (August 2026)](https://www.utpplan.com/DOC/Nasdaq%20UTP%20SIP%20Extended%20Trading%20Hours%20FAQ%20Finalized%20Version%201.2.pdf) — UTP Plan, read 2026-10-08
5. [CTS Pillar Multicast Output Binary Specification (Extended Trading Hours), version 2.12b](https://www.ctaplan.com/publicdocs/ctaplan/CTS_Pillar_Output_Specification_ETH.pdf) — Securities Industry Automation Corporation, 2026-07-01
6. [Extended-Hours Trading Frequently Asked Questions, v4.0 (August 2026)](https://www.nyse.com/publicdocs/nyse/NYSE_Extended_Hours_Trading_FAQ.pdf) — New York Stock Exchange (NYSE Arca), read 2026-10-08
7. [Nasdaq global trading hours, Frequently Asked Questions](https://www.nasdaq.com/docs/nasdaq-global-trading-hours-faqs) — Nasdaq, Inc., read 2026-10-08
8. [Cboe U.S. Equities Overnight Trading FAQ](https://www.cboe.com/document/tech-spec/content/technical-specifications/cboe-u.s.-equities-overnight-trading-faq) — Cboe Global Markets, 2026-09-23
9. [Nasdaq order granting accelerated approval to extend trading hours to 23 hours a day, five days a week, Release No. 34-105199](https://www.sec.gov/files/rules/sro/nasdaq/2026/34-105199.pdf) — U.S. Securities and Exchange Commission, 2026-04-10
10. [Cboe EDGX order granting accelerated approval to extend trading hours to 23 hours per day, five days per week, Release No. 34-105587](https://www.sec.gov/files/rules/sro/cboeedgx/2026/34-105587.pdf) — U.S. Securities and Exchange Commission, 2026-05-29
11. [FINRA notice of filing to extend Trade Reporting Facilities operating hours to 23 hours per day, five days per week, Release No. 34-105922 (SR-FINRA-2026-015)](https://www.sec.gov/files/rules/sro/finra/2026/34-105922.pdf) — U.S. Securities and Exchange Commission, 2026-07-15
12. [Order Granting Temporary Conditional Exemptive Relief to 24X National Exchange LLC, Release No. 34-106061](https://www.sec.gov/files/rules/exorders/2026/34-106061.pdf) — U.S. Securities and Exchange Commission, 2026-08-07
13. [Historical Stock Data (feed parameter)](https://docs.alpaca.markets/us/docs/historical-stock-data-1) — Alpaca, read 2026-10-08
14. [Market Data FAQ](https://docs.alpaca.markets/us/docs/market-data-faq) — Alpaca, read 2026-10-08
15. [How to view the overnight session (24h) on your chart](https://www.tradingview.com/support/solutions/43000790593-how-to-view-the-overnight-session-24h-on-your-chart/) — TradingView, read 2026-10-08
16. [US equities move to 23/5 trading](https://massive.com/blog/us-equities-move-to-23-5-trading) — Massive, 2026-08-26

*Last updated 2026-10-08. A reference page, corrected in place — not a dated post.*