What does halt code LUDP mean? Volatility Pause (LULD)
A Limit Up-Limit Down pause. Trading in the stock stopped because the price moved outside its allowed band too quickly.
How long a LUDP halt actually lasts
Measured from our own halt feed across 312 LUDP halts that published a resume time, 2026-07-20 to 2026-08-21. The median is used rather than the average because halt lengths are heavily skewed, and a handful of long ones would drag a mean somewhere no individual halt has ever been.
What triggers it
The stock tried to trade beyond a price band set from its recent average. The band is a percentage that depends on the price of the stock and the time of day, and it is tighter for lower-priced names.
What happens next
These are short and mechanical. Trading reopens once the exchange runs a reopening auction, and the stock can halt again immediately if it keeps moving.
Recent LUDP halts
| Stock | Date | Halted for | Day move |
|---|---|---|---|
| AMCI | 2026-08-21 | 10 min | +10.89% |
| BMGL | 2026-08-21 | 5 min | +0.00% |
| FVNNU | 2026-08-21 | 5 min | +0.00% |
| AIFU | 2026-08-21 | 5 min | +0.00% |
| PHOS | 2026-08-21 | 5 min | +8.78% |
| SUGP | 2026-08-21 | 20 min | -13.73% |
| USDE | 2026-08-21 | 5 min | +9.61% |
| BCARU | 2026-08-21 | 6 min | +0.00% |
| ZSTK | 2026-08-21 | 10 min | +0.00% |
| RDACU | 2026-08-21 | 6 min | +0.00% |
| MFI | 2026-08-21 | 10 min | +0.00% |
| JUNS | 2026-08-21 | 10 min | +2.07% |
LUDP halts: common questions
- What does halt code LUDP mean?
- A Limit Up-Limit Down pause. Trading in the stock stopped because the price moved outside its allowed band too quickly. On the halt feed it shows as "Volatility Pause (LULD)".
- How long does a LUDP halt last?
- Across 312 LUDP halts where we captured a resume time, the median was 5 min, and nine out of ten resumed within 11 min. That is measured from our own halt feed, not an estimate. Individual halts vary and the exchange sets the actual resume time.
- What triggers halt code LUDP?
- The stock tried to trade beyond a price band set from its recent average. The band is a percentage that depends on the price of the stock and the time of day, and it is tighter for lower-priced names.
- What happens when the LUDP halt lifts?
- These are short and mechanical. Trading reopens once the exchange runs a reopening auction, and the stock can halt again immediately if it keeps moving.
- Can I trade a stock while it is halted?
- No. A halt stops trading on every US exchange at once, so no orders execute until the stock reopens. Orders can still be placed and cancelled, and the reopening auction can print well away from the last traded price.