Trading · Rules and regulations
Trading halts and Limit Up-Limit Down (LULD) pauses explained
Why US stocks get halted, how news-pending halts and SEC suspensions differ, and how LULD price bands, limit states and 5-minute pauses work, with examples.
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Sometimes a stock simply stops trading. The quote freezes, orders sit unfilled, and a code appears next to the symbol. In the US that happens for two broad reasons: someone with authority decides investors need information before trading continues, or the price has moved so fast that an automatic safeguard steps in. The first is a trading halt. The second is usually a Limit Up-Limit Down (LULD) pause.
Both are routine. LULD pauses occur most often in small, volatile stocks, and news-pending halts happen around mergers, clinical-trial results and other material announcements. This guide explains each type, how the LULD price bands are calculated as of 2026, what a limit state and a trading pause are, and what a halt means for orders you have resting in the market.
Two families of halts
Regulatory halts
A regulatory halt is called by the stock's listing exchange, and once it is in place every trading venue must stop trading the stock. Common reasons, using the codes Nasdaq publishes on its halt list:
- News pending (T1). The company is about to release material news, such as a merger, bankruptcy filing or drug-trial result, and the exchange halts so everyone can read it before trading resumes. Often followed by news released (T2) and a scheduled resumption.
- Additional information requested (T12). The exchange has asked the company for information, for example about unusual trading or a rumor.
- Regulatory concern (H11), a halt in conjunction with another exchange or market for regulatory reasons, or not current in filings (H9), when the company is behind on its required reports.
- Volatility trading pause (LUDP). An automatic LULD pause, described below.
- Market-wide circuit breaker (MWC1–MWC3). All stocks halt together; see Market-wide circuit breakers: the 7%, 13% and 20% halt rules.
SEC trading suspensions
An SEC trading suspension is different from an exchange halt. Under the Securities Exchange Act, the SEC can suspend trading in any stock for up to ten business days when it believes investors need protection, for example because there are questions about the accuracy of a company's information or signs of manipulation. Nasdaq lists these as H10. Exchange-listed stocks can resume when the suspension ends; over-the-counter stocks often cannot, because a broker-dealer has to meet SEC and FINRA requirements before quoting them again. Investor.gov advises extra caution with any stock that has been suspended.
Non-regulatory halts
A non-regulatory halt is one a single venue imposes for its own reasons, typically an operational or technical problem on that exchange. Other venues can generally keep trading the stock. These are rare and usually brief, and most investors only notice them as an exchange outage.
How LULD works
The Limit Up-Limit Down Plan was adopted after the May 6, 2010 "Flash Crash" and replaced the earlier single-stock circuit breakers. It applies to all US exchange-listed (NMS) stocks and ETFs, except rights and warrants, from 9:30 a.m. to 4:00 p.m. Eastern Time. Its aim is to stop trades at prices far from where the stock was trading moments earlier, without stopping the market entirely.
Step 1: the reference price
The reference price is the arithmetic mean price of eligible trades in the stock over the preceding five minutes. It updates continuously, so the bands follow the stock as it moves, just with a lag. A gradual move, however large, can go on all day without touching the bands; a sudden one cannot.
Step 2: the bands
The bands are a percentage above and below the reference price. The percentage depends on the stock's tier and its prior closing price:
- Tier 1: stocks in the S&P 500 and Russell 1000, plus selected exchange-traded products.
- Tier 2: all other NMS stocks. All leveraged ETPs are Tier 2.
| Prior close | Tier 1 | Tier 2 |
|---|---|---|
| Above $3.00 | 5% | 10% |
| $0.75 to $3.00 | 20% | 20% |
| Below $0.75 | Lesser of $0.15 or 75% | Lesser of $0.15 or 75% |
Doubling at the close. As of 2026, the percentages double during the last 25 minutes of regular trading, 3:35 to 4:00 p.m., for all Tier 1 stocks and for Tier 2 stocks priced at or below $3.00. Tier 2 stocks above $3.00 are not doubled. Older sources often say bands are also doubled during the first 15 minutes after the open; that provision was removed, and there is no opening doubling today.
Step 3: the limit state
When the best offer falls to the lower band (or the best bid rises to the upper band), the stock enters a limit state. Trading continues, but only at prices inside the band; trades outside it are not allowed. Many limit states clear on their own as buyers or sellers step in and the quote moves back inside the band.
Step 4: the trading pause
If the limit state does not clear within 15 seconds, the primary listing exchange declares a five-minute trading pause across all venues. The stock then reopens through an auction on the listing exchange. If the auction cannot match buyers and sellers at a reasonable price, the pause can be extended by another five minutes. A pause triggered during the last 10 minutes of the session is not reopened; the listing exchange runs its closing process instead.
What a halt or pause means for your orders
- Resting limit orders generally stay on the book through a halt and can participate in the reopening auction. Policies differ by broker and exchange, so check yours.
- Stop orders can trigger at the reopening price, which may be far from the stop price. A stock that reopens 20% lower after news fills a sell stop near the reopening price, not the stop price.
- Market orders entered during a halt are executed at the reopening, at whatever price the auction sets.
- Options on a halted stock also stop trading, but their value keeps changing with the news, so the reopening can be abrupt.
Halts and pauses compared
| Type | Who decides | Typical length | Applies to |
|---|---|---|---|
| News pending (T1) | Listing exchange | Minutes to hours | One stock, all venues |
| SEC trading suspension (H10) | SEC | Up to 10 business days | One stock, all venues |
| LULD trading pause | Automatic (plan rules) | 5 minutes, extendable | One stock, all venues |
| Non-regulatory halt | A single venue | Usually brief | That venue only |
| Market-wide circuit breaker | Automatic (S&P 500 decline) | 15 minutes or rest of day | All stocks and options |
| Short sale restriction (Rule 201) | Automatic (10% drop) | Not a halt: rest of day plus next day | Short sales in one stock |
The last row is included because SSR is often confused with a halt. It is not: everyone except short sellers hitting the bid can trade normally. See Short sale restriction (SSR) rule: how SEC Rule 201 works.
Pitfalls
- Reading a pause as a signal. A LULD pause says the price moved fast, not which way it will go next. Reopening prices can continue the move or reverse it.
- Using old band rules. Many explanations still describe doubled bands at the open. As of 2026 only the last 25 minutes are doubled, and only for some stocks.
- Ignoring extended hours. LULD applies only from 9:30 a.m. to 4:00 p.m. ET. Pre-market and after-hours moves are not limited by the bands, which is one reason those sessions can see very large swings on thin volume.
- Holding through news without a plan. Halts cluster around scheduled events. A position held into an announcement can reopen at a price that no order could have controlled.
How Finabase helps
Finabase is a research app and does not route orders, so it neither imposes nor displays halt codes. What it shows can help you understand the cause and the context: the news feed and each symbol page's news tab collect the headlines that often accompany a news-pending halt, the trending page highlights stocks with unusual activity in the regular session, pre-market and after hours, and alerts can notify you of price levels without relying on a stop order that might fill at a reopening price. For the official halt status, check your broker or the listing exchange's halt list.
Frequently asked questions
What does it mean when a stock is halted?
Trading in the stock has stopped on every US venue, usually because news is pending or because the price moved fast enough to trigger an automatic LULD pause. Orders can usually still be entered or cancelled, but nothing executes until trading resumes.
How long does a trading halt last?
A LULD pause lasts five minutes, sometimes extended by another five. A news-pending halt usually lasts until the news is out plus a short period for investors to read it, often under an hour. An SEC suspension can last up to ten business days.
Why are LULD bands wider in the last 25 minutes?
The plan doubles them from 3:35 to 4:00 p.m. for Tier 1 stocks and Tier 2 stocks at or below $3, allowing more price movement around the closing auctions so that ordinary end-of-day volatility does not cause pauses.
Do LULD bands apply in pre-market or after-hours trading?
No. As of 2026 the LULD bands apply only during regular trading hours, 9:30 a.m. to 4:00 p.m. Eastern Time. Extended-hours trading has no LULD bands.
Summary
US trading stops for two reasons: to let information reach everyone before prices react, and to keep prices from leaping in seconds. Regulatory halts and SEC suspensions handle the first; the Limit Up-Limit Down plan handles the second with bands around a five-minute average price, a 15-second limit state and a five-minute pause. As of 2026 the bands are 5%, 10% or 20% for most stocks and double only in the last 25 minutes for Tier 1 and low-priced Tier 2 names. Knowing the rules explains the frozen quote, and knowing that halts create gaps explains why no order type can fully protect a position held through one.