Are halt codes the same on every exchange?

The codes covered here come from Nasdaq Trader's halt code list. The NYSE publishes its own halts page, so for an NYSE-listed stock, check that page for the reason it gives.

Can I sell a stock while it's halted?

No trades happen while the halt lasts. Whether you can queue an order for the reopen, or cancel one already waiting, depends on your broker, so check its documentation.

My broker shows the stock as halted but gives no code. Where do I find it?

Look up the symbol on the listing exchange's halt page. Many platforms show the code next to the quote, and some only show a frozen price.

Can the code change while the stock is still halted?

Yes. A news halt can go from T1 to T2 once the news is out, then to T3 when the exchange sets the quoting and trading times.

Trading Halt Codes Explained: T1, LUDP, H10 and More

Trading halt codes are the short labels an exchange attaches to a halted stock to say why trading stopped. On Nasdaq’s published list, T1 means a halt with news pending, LUDP means a limit up-limit down volatility pause, and H10 means the SEC has suspended trading in the stock. Read the code first. It tells you what kind of wait you’re in, which matters a lot more than the frozen last price sitting on your screen.

Some codes clear in minutes. Others can hold a position still for days, and the code is usually the fastest way to tell which kind you’re looking at.

How the codes are built

Nasdaq Trader keeps the list. The codes follow a loose pattern: most T codes deal with news and single-stock pauses, the H codes cover regulatory and compliance trouble, the LUD codes are volatility pauses, and the MWC codes belong to the market-wide circuit breakers, while a handful of others (O1, IPO1, M1, M2) cover operations, new listings, corporate actions and missing quotes.

The pattern has holes. T8 is a halt on an exchange-traded fund, T6 is a halt for extraordinary market activity, and T12 means Nasdaq has asked for additional information, which reads more like the H group than the news group. So learn the handful you’re likely to meet. Look up the rest when one appears.

The common codes, grouped by what they mean for you

The labels below follow Nasdaq Trader’s halt code list, sorted by the kind of wait each one usually means.

What it means for you	Code	Label on the list
News halt, usually reopens	T1	News pending
News halt, usually reopens	T2	News released
News halt, usually reopens	T3	News and resumption times
Volatility pause (LULD)	LUDP	Volatility trading pause
Volatility pause (LULD)	LUDS	Volatility trading pause, straddle condition
Single-stock pause	T5	Single stock trading pause in effect
Single-stock pause	T7	Single stock trading pause/quotation-only period
Regulatory or filing, can run much longer	T12	Additional information requested by Nasdaq
Regulatory or filing, can run much longer	H4	Non-compliance
Regulatory or filing, can run much longer	H9	Not current in required filings
Regulatory or filing, can run much longer	H10	SEC trading suspension
Regulatory or filing, can run much longer	H11	Regulatory concern
Market-wide halt	MWC1, MWC2, MWC3	Market-wide circuit breaker halt, levels 1 to 3
Market-wide halt	MWC0	Carried over from the previous day
Market-wide halt	MWCQ	Market-wide circuit breaker resumption
Operational or other	T6	Extraordinary market activity
Operational or other	T8	Exchange-traded fund (ETF)
Operational or other	O1	Operations halt
Operational or other	IPO1	IPO issue not yet trading
Operational or other	M1	Corporate action
Operational or other	M2	Quotation not available
Trading restarts	R4, R9, C3, C4, C9, C11	Resumption codes

News halts: T1, T2 and T3

T1 means news is pending. The exchange has stopped trading so that information about the company reaches everyone before anyone trades on it again. The code says nothing about whether the news is good or bad. Guessing direction from a T1 is just guessing.

T2 means the news is out. T3 then gives two times, first the time quoting resumes and then the time trading does, and that gap is worth paying attention to, because during the quoting window you can watch where bids and offers settle before a single share changes hands, which is about as close to a preview of the reopening price as you’ll get.

News halts usually reopen. The open question is where. The first price comes from whatever orders are waiting, so it can land well away from the last trade before the halt. How your own resting orders are treated depends on your broker, and the mechanics are laid out in what happens when a stock you own is halted.

Volatility pauses: LUDP, LUDS, T5 and T7

LUDP is a limit up-limit down volatility pause. Under limit up-limit down, a stock that stays at its band limit for 15 seconds goes into a 5-minute pause. LUDS is a volatility pause flagged with a straddle condition, which the list names as its own code.

These are mechanical. Nobody decided the company had a problem; the price moved too fast for its bands and the rule fired. In one sense that makes LUDP the least alarming code on the list. It’s also one of the rougher ones for stops, since a stock that pauses at its lower band has no trades between the last print and wherever it reopens, and a stop sitting in that empty stretch can’t trigger until trading resumes, at which point it fills near the reopening price.

T5 and T7 also describe single-stock trading pauses. T7 adds a quotation-only period, so quotes can move while trades can’t, and that window deserves the same attention as the T3 quoting window: it shows you where the other side is lining up.

Regulatory and filing halts: the H codes and T12

These are the codes to worry about. H4 is non-compliance. H9 means the company isn’t current in its required filings. H11 is a regulatory concern, and T12 means Nasdaq has asked for more information. H10 is the heavy one, because the SEC itself has suspended trading.

Expect these to last longer. A news halt waits for an announcement, while a regulatory or filing halt waits for a problem to be dealt with, and that can take much more time. SEC suspensions can last days. You can’t trade the shares while any of these is in force, so the real decision comes before the halt, when you choose how much of the account to put into a name that’s behind on its filings or already drawing regulatory attention, knowing that position could be frozen for a stretch nobody can predict.

When a halt runs past the close and into another session, the reopen behaves much like an overnight gap down. Everything that piled up while the stock was dark gets priced at once. If the reason for the halt turned out badly, that first print can sit far below where your stop was.

Market-wide circuit breakers: the MWC codes

MWC codes stop everything. They’re triggered by declines in the S&P 500 from the prior close. Level 1 is a 7% drop and Level 2 is a 13% drop, and either one halts all trading for 15 minutes if it’s hit before 3:25 p.m. Eastern. Level 3, at 20%, halts trading for the rest of the day.

MWC1, MWC2 and MWC3 mark those three levels. MWC0 means the halt carried over from the previous day, and MWCQ marks the market-wide resumption. If an MWC code shows up on a stock you hold, the cause is the whole market, and every stock position in your account is frozen along with it, which changes what you should be thinking about: your total exposure, more than any single name.

The rest of the list

O1 is an operations halt. IPO1 marks a new issue that isn’t trading yet. M1 covers a corporate action, and M2 means a quotation isn’t available. The two odd T codes from earlier, T6 and T8, belong here too: one flags extraordinary market activity, the other an ETF.

Then there are the resumption codes: R4, R9, C3, C4, C9 and C11. They sit on the restart side of a halt. When one appears next to a symbol you were watching, check Nasdaq’s list for its exact wording before you place anything.

Following a halt on your own position

Say you hold 300 shares and the last trade before a T1 halt printed at 24.00. Your account keeps showing the position at that price, because it’s the last one it has. T2 appears. Then T3, with a quoting time and a trading time. Suppose the stock reopens at 21.60.

Nothing in the account moved while the stock was halted. The 720.00 was settled by the orders waiting for the reopen, and the last moment you could have changed your exposure to it was before the T1 went up. That’s the uncomfortable part of halts. The loss happens in a period when you can watch it form and do very little.

Where to see the code

The exchange’s halt list is the source: Nasdaq Trader for Nasdaq’s codes, the NYSE halts page for NYSE-listed stocks. Many broker platforms show the code too, usually as a status next to the quote. If yours shows only a frozen price, look the symbol up on the exchange page.

When something you own stops trading, run through a short check.

Find the code.
Match it to its group in the table.
If it’s a T3, write down both times.
Check what your broker lets you do with orders during the halt.
Decide what, if anything, you want waiting for the reopen.

Order handling during a halt is broker dependent, so the time to read your broker’s rules on cancels and queued orders is before you own something that halts, when you can read them calmly and the answer can still change how you size the position.