Nasdaq halt codes T1 and T12 are both regulatory halts, but they have different triggers. T1 means news is pending: the company is about to release something material. T12 means Nasdaq has asked the company for more information, often because the stock is moving and nobody knows why. LUDP is a five-minute volatility pause. H10 means the SEC suspended trading.
This post is the US code reference. If you want the bigger question of whether a halt is good or bad and what tends to happen after one in the US and Canada, read our general guide to trading halts. Here we stay on the codes themselves, straight from the Nasdaq Trader halt codes page, and on what you should check in the minutes after each one shows up on a small cap.
In this article
- Nasdaq halt codes T1 and T12: what is the difference?
- Nasdaq halt and resume codes in plain English
- Who issues Nasdaq halts and how do they work?
- What happens after a T1 halt on a small cap?
- How long does a T12 halt last, and is it bad?
- LUDP vs T5: why does a stock pause with no news?
- What about T13, T14, T15 or T20?
- A checklist for any Nasdaq halt
- FAQ
Nasdaq halt codes T1 and T12: what is the difference?
T1 is a halt because news is coming; T12 is a halt because Nasdaq wants answers from the company.
A T1 is usually tied to a planned release. The company has material news (a deal, trial data, a financing) and trading stops so the information reaches everyone at the same time. It typically resolves once the news is out.
A T12 is different. Nasdaq has requested additional information from the issuer. On small caps you often see it after a ticker rips with no filing and no press release behind it. There is no promised news at the end, and no fixed clock.
Nasdaq halt and resume codes in plain English
The official names below come from the Nasdaq Trader halt codes list. The right-hand column is our read on what usually follows on a small cap. It describes common patterns, not rules, and every case is different.
| Code | Official name | Plain English | What typically follows on a small cap |
|---|---|---|---|
| T1 | Halt – News Pending | Material news is about to be released | Press release on the wire, often an 8-K or a 424B prospectus supplement on EDGAR within minutes |
| T2 | Halt – News Released | The news is out; the halt continues so it can be digested | Read the release and the filing before the resume quote opens |
| T3 | News and Resumption Times | Resume code that posts the quote time and trade time | Quote-only window, then trading restarts through a halt cross |
| T12 | Halt – Additional Information Requested by Nasdaq | Nasdaq wants information from the company | Can be short or drag on; may end with a statement, a filing, or a resume with no news |
| LUDP | Volatility Trading Pause | Limit Up-Limit Down pause, no news needed | Five-minute pause, then reopen; runners can stack several in a row |
| LUDS | Volatility Trading Pause – Straddle Condition | Pause triggered by a quote straddling the LULD band | Similar to LUDP; usually short |
| T5 | Single Stock Trading Pause In Effect | Older single-stock pause code | Largely replaced by LUDP in day-to-day small-cap trading |
| T6 | Halt – Extraordinary Market Activity | Unusual activity, e.g. systems or erroneous trade issues | Check for clearly erroneous trade busts before assuming prints will stand |
| T8 | Halt – Exchange-Traded Fund (ETF) | Halt on an exchange-traded product | Rare in small caps; tied to the product, not an operating company |
| H4 | Halt – Non-compliance | Listing rule problem | Look for deficiency notices and delisting filings |
| H9 | Halt – Filings Not Current | Required reports are late | Check EDGAR for NT 10-K or NT 10-Q notices |
| H10 | Halt – SEC Trading Suspension | The SEC suspended trading | Can last up to 10 trading days; listing status often comes into question |
| H11 | Halt – Regulatory Concern | Nasdaq has a regulatory concern about the security | Often lengthy; watch for delisting determinations |
| MWC1-3 | Market Wide Circuit Breaker Halt | The whole market stopped on an S&P 500 drop | Not about your ticker at all; everything halts together |
Resume codes you will see on the same page:
- C3: issuer news not forthcoming, trading to resume. Translation: the halt lifts and no news came out. Common after T1s or T12s that went nowhere.
- R4 / C4: qualification issues resolved, trading to resume.
- R9 / C9: filing requirements satisfied, trading to resume. Often the end of an H9.
- C11: halt concluded by another regulatory authority, trading to resume. You see this after an SEC suspension ends.
Who issues Nasdaq halts and how do they work?
Nasdaq, as the listing market, issues the regulatory halts (T1, T2, T12 and the H codes), and other US venues honor them, so the stock stops everywhere, not just on Nasdaq.
LUDP pauses are mechanical. They come from the Limit Up-Limit Down plan: if a stock sits at the edge of its price band for 15 seconds, it pauses for five minutes. Nobody at Nasdaq decided anything.
H10 comes from the SEC, which can suspend trading in any stock for up to 10 trading days. The SEC lists these on its trading suspensions page.
Market-wide circuit breakers trigger on S&P 500 drops of 7% (Level 1), 13% (Level 2) and 20% (Level 3) from the prior close. Levels 1 and 2 halt for 15 minutes if hit before 3:25 pm ET. Level 3 ends the day.
When a Nasdaq-listed stock comes back, it usually reopens through a halt cross: a quote-only period where orders build up, then a single opening print. The Nasdaq Trader current halts page shows the resumption quote time and trade time once they are set.
What happens after a T1 halt on a small cap?
The news drops, and on a small cap the first job is to find out whether that news is a deal or a financing.
Hypothetical: a $2 biotech is up 40% by 10:30 and halts T1. Within minutes there are two very different ways this can go. One: an 8-K hits EDGAR with Item 1.01, a licensing agreement. Two: a press release announces a proposed offering and a preliminary prospectus supplement lands on EDGAR as a 424B5. Same halt code, opposite setups.
Here is what to check while it is halted:
- Open EDGAR and pull the company’s newest filings.
- If it is an 8-K, read the item numbers first. Our 8-K items guide covers which ones tend to matter.
- If it is a 424B, find the share count, price, warrants and closing date. How to read a 424B5 walks through it.
- Foreign issuers often file a 6-K instead of an 8-K, so do not assume no 8-K means no news.
Why it matters: in Fockets Terminal data, runs on a priced offering closed down 4.3% on average and 65% faded, while runs on an 8-K closed up 3.5%. That is a tendency across many tickers, not a prediction for yours. But it shows why the filing behind the halt matters more than the halt itself.
How long does a T12 halt last, and is it bad?
There is no set length for a T12; it can lift the same day or stretch on for days or longer, and the risk is that you cannot exit while it lasts.
A T12 is not automatically bad. Sometimes the company answers, puts out a statement saying it knows of no undisclosed news, and the stock resumes. Sometimes it resumes on C3 with nothing at all. But on small caps that ran hard with no catalyst, a T12 is a warning that Nasdaq is looking closely, and a long one can move toward an H11 or a delisting process.
The practical takeaway: if you are holding a no-news runner, size for the possibility that a T12 freezes your position for longer than you planned.
T12 vs H10: Nasdaq halt or SEC suspension?
A T12 is Nasdaq asking the company questions. An H10 is the SEC using its power to stop trading, usually citing concerns about the accuracy of public information or possible manipulation. H10 is the heavier of the two. After it ends, the exchange decides whether the stock resumes or heads toward delisting.
LUDP vs T5: why does a stock pause with no news?
LUDP means the price moved too far, too fast for its LULD band; it says nothing about news.
A low float can print three or four LUDPs before lunch on the way up. On the way down, the same pauses can stack, and once a stock drops 10% from the prior close the short sale restriction kicks in too. See what SSR changes on an offering day. T5 is the older single-stock pause code; in practice LUDP is what you will see on a fast mover.
A pause is still a good moment to check EDGAR. Sometimes a filing landed seconds before the move and nobody had read it yet.
What about T13, T14, T15 or T20?
Those codes are not on the Nasdaq Trader list we reference here. If a scanner or forum post shows a code you do not recognize, check the official Nasdaq Trader page or the vendor’s documentation rather than guessing. Other exchanges and data vendors use their own codes.
A checklist for any Nasdaq halt
- Read the code: news (T1/T2), question (T12), mechanical (LUDP), regulatory (H codes) or market-wide (MWC).
- Pull the latest EDGAR filings: 8-K, 6-K, 424B, S-1 or S-3.
- If it is a financing, find the price, share count and warrants before the reopen.
- Watch the resume code: T3 with news, or C3 with none.
- Decide your risk before the halt cross, not during the first print.
The free Nasdaq Trader halts page is the source of record for real-time halts. The Fockets Terminal does the filing side: it ties big moves to the filing behind them (offering, 8-K, insider buy, or nothing) and rescans about 13,000 US stocks every 30 seconds, so you are not hunting through EDGAR by hand when a halt lifts.
FAQ
Does a T1 halt mean the stock is about to go up?
No. T1 only means news is pending. On small caps that news can be a contract or an offering, and the two often trade very differently.
Can I sell during a halt?
Nothing executes on US exchanges while a stock is halted. Some brokers let you enter or cancel orders for the reopening cross; check your broker’s rules.
Can a T12 halt lead to delisting?
It can, but it does not have to. Many T12s resume. A long T12 that turns into an H11 or a delisting determination is the scenario to respect.
What is the difference between T1 and T2?
T1 means the news has not come out yet. T2 means it has been released and the stock is still halted so the market can absorb it before trading resumes.
If you want to see how other traders read a halt in real time, which filing they pull and how they think about risk around the reopen, come into the free Fockets stock trading Discord. Ask questions, share your own read, and build the habit of checking the filing yourself.
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Disclaimer: This post is for educational purposes only and is not financial advice. Fockets Trading does not make buy or sell recommendations. Trading small caps and halted stocks carries significant risk, including the loss of your entire investment. Always do your own research and size your own risk.
