LULD halt (limit up-limit down)
A LULD halt is a five-minute trading pause under the Limit Up-Limit Down plan, called when a stock reaches the edge of its price band and stays there for 15 seconds. The bands sit a set percentage above and below the stock's average price over the last five minutes, to stop sudden, extreme moves in US stocks.
Why it matters to a small-cap momentum trader
Low-float momentum stocks reach their bands far more often than large caps, so pauses are part of trading them. A stock that pauses at its upper band, limit up, often reopens higher, but not always, and you cannot get out while it is paused. Knowing roughly where the next band sits tells you how far a stock can run before it pauses, and where a stop may not fill. During the pause market orders do not fill, nothing prints on the tape, and the reopening auction sets the next price.
The rule
Reference price. The average price of eligible trades over the preceding five minutes. Band edges are rounded to the nearest penny, and bands apply only in regular hours, 9:30 a.m. to 4:00 p.m. ET.
Tiers. Tier 1 is the S&P 500, the Russell 1000 and some exchange-traded products. Tier 2 is every other listed stock, except rights and warrants, which have no bands. Almost every small cap is Tier 2.
Band width. Picked from the previous day's closing price and fixed for the whole day:
| Previous close | Tier 1 | Tier 2 |
|---|---|---|
| Above 3 dollars | 5% | 10% |
| 75 cents to 3 dollars | 20% | 20% |
| Below 75 cents | 15 cents or 75%, whichever is less | 15 cents or 75%, whichever is less |
Limit state and pause. When the best offer sits at the lower band, or the best bid at the upper band, the stock is in a limit state and its bands stop moving. If it does not leave the limit state within 15 seconds, the listing exchange pauses trading for five minutes and reopens the stock with an auction. The pause runs longer if the auction cannot open.
Because the width comes from the previous close, a stock that closed under 75 cents keeps its 15-cent band all day, even after it runs past 3 dollars.
The rule depends on the date: Amendment 18
The band has doubled near the open and the close, and which windows double changed on 24 February 2020, when Amendment 18 to the LULD plan took effect.
- Before 24 February 2020: the band doubled for every stock in the first 15 minutes, 9:30 to 9:45 a.m. ET, and the last 25 minutes, 3:35 to 4:00 p.m. ET.
- From 24 February 2020: no opening doubling. The closing doubling, 3:35 to 4:00 p.m. ET, applies only to Tier 1 stocks and to Tier 2 stocks whose previous close was 3 dollars or less. A Tier 2 stock that closed above 3 dollars keeps its 10% band all day. On a half-day, the closing window is the last 25 minutes before the 1:00 p.m. close.
LULD in Hindsight Markets
Bands are worked out from that day's trades by the plan's formula, under the rules in force on the date you replay, and no fill goes through a band. The pauses are the ones that really happened that day, from the exchanges' own halt messages. The Level 2 picture on the home page is MEDS paused at 10:48 ET on 2026-09-16: no prints on the tape while the book kept streaming.
A worked example: the bands on a 2.50 stock
An illustration, not a real stock or a real day. A Tier 2 stock closed yesterday at 2.50, so its band today is 20%, from the table above.
10:05 a.m. The average price of the last five minutes of trades is 2.80. Upper band = 2.80 × 1.20 = 3.36. Lower band = 2.80 × 0.80 = 2.24.
Limit up. Buyers lift every offer and the best bid reaches 3.36. The stock is in a limit state. If the bid is still at 3.36 fifteen seconds later, trading pauses for five minutes.
3:40 p.m. The previous close was 3 dollars or less, so from 2020 on the band doubles to 40% in the last 25 minutes. Around the same 2.80 reference, that is 1.68 to 3.92.
Had it closed at 3.50. The band would be 10% all day, with no closing doubling: around a 4.00 reference, 3.60 to 4.40.
Common mistakes small-cap traders make with LULD
- Chasing into the upper band. A buy at the band is the highest price the market allows before a pause, and the reopening auction can open lower.
- Counting on a stop during a pause. Nothing trades while the stock is paused, so a stop cannot fill there. The stock can reopen well past it.
- Working out the band from the open. The reference is the average of the last five minutes, and the percentage comes from yesterday's close. Neither is today's opening price.
- Applying today's rule to an old chart. Before 24 February 2020 every band doubled in the first 15 minutes. A pause at 9:40 on an old day was measured against a wider band than it would be now.
Common questions
- How long is a LULD halt?
- Five minutes. If the reopening auction cannot open within its price limits, the pause is extended by another five minutes, and it can be extended again.
- Can you sell during a LULD halt?
- No trades happen during the pause, buying or selling. Many brokers let you place or cancel orders that wait for the reopening auction, which sets the first price after the pause.
- What is the difference between a LULD pause and a news halt?
- A LULD pause is automatic, set off by price, and lasts about five minutes. A news halt is called by the listing exchange, often while news is pending, and lasts until the exchange reopens the stock. On Nasdaq's halt list a LULD pause carries the code LUDP and a news halt T1.
- How are LULD bands calculated?
- Take the average price of eligible trades over the last five minutes and add and subtract the band percentage, then round to the penny. Odd lots do not count. A new band is issued only when that average moves 1% or more, and after a pause the reopening price becomes the new reference.
- Do LULD bands apply in the pre-market or after hours?
- No. The bands run only from 9:30 a.m. to 4:00 p.m. ET, so a pre-market move has no band and no LULD pause.
How to practise it in Hindsight Markets
- Open a past trading day and run the Small Cap Low Float Top Gainers scan to find a stock that is running.
- In the chart settings, turn on LULD bands. Two lines, LULD↓ and LULD↑, show the bounds, and the Level 2 header shows the same two prices.
- Slow the replay to half speed as the price nears a band, and decide what you will do before it gets there.
- Watch the pause: the Level 2 header reads Paused, the chart shades the pause, and the tape stops until trading resumes.
- Open the trade in the journal and compare Most against you with where your stop was.
Practice this on a real past day in Hindsight Markets
Replay a morning when a small cap ran into its bands, watch the pause and the reopen in real time, and see where your orders would have filled.