Why do trading halts occur and when do they resume?
A trading halt is a temporary suspension of trading. Check the reason for the halt and the resumption information separately.
Table of contents
Remember this first
First, 3 things to remember
- 1Trading may be halted due to rapid price changes or significant news.
- 2A halt code is an indicator that explains the reason for the suspension.
- 3The expected resumption time and the official resumption time are different.
Codes are abbreviated indicators of the reason for the halt.
Halts can occur due to rapid price fluctuations or while waiting for significant news. LULD is the name of the mechanism for handling price volatility, while LUDP, M, and T1 are codes used by Nasdaq Trader to categorize the reasons for a halt.
In the community, 'up-circuit' and 'down-circuit' are terms used to refer to halts related to upward or downward price movements. Do not assume all trading halts are for the same reason or duration.
| Code | Meaning | Things to check |
|---|---|---|
| LUDP | Temporary halt due to rapid price fluctuation | Resumption notice/quote status |
| M | Volatility halt for securities listed on Market Category C exchanges. | Original halt code and official resumption information |
| T1 | Waiting for news announcement | Company/Exchange announcements |
| T2 | News pending | Follow-up resumption information |
A 5-minute estimate is not a promise to resume after 5 minutes.
The WAPE estimated time is a calculation provided as a reference while waiting on the screen. It is not an official announcement from the exchange guaranteeing that trading will resume at that exact time. The wait may be longer depending on the situation.
If trading does not resume when the timer ends, check the official resumption information and screen updates. Do not assume that an increase in time means the exchange has officially announced an extension.
The price may change when trading resumes.
Orders and expectations may change during a halt. When trading resumes, it may occur at a different price than just before the halt.
First, check the stock name, reason for the halt, time of the halt, and whether an official resumption has been announced in order. Do not assume you can sell at your desired price immediately during a halt.
Quotes or expected auction prices moving during a halt do not guarantee a rise or fall after resumption. Data ranges may also vary by brokerage. See the LUDP/M quote guide in the follow-up reading for more details.
You should not make such assumptions
“If the halt countdown is 0, does trading definitely resume immediately?”
The expected time provided by the service and the official resumption by the exchange are different. You must check the actual announcement.
Check what you have read.
- Have you checked the halt reason code?
- Have you checked the halt time and the latest announcement?
- Have you distinguished between the expected time and the official resumption?
Apply what you read to the actual screen
Try it on WAPE
Source and scope of verification
Reviewed · Version 3
- Trading Halts CodeNew window
Nasdaq Trader · Verify 2026-10-20
Meanings of official codes such as LUDP, M, T1, and T2, and the distinction between quotes and trading resumption - The NYSE Advantage · LULD HaltsNew window
NYSE · Verify 2026-10-20
Minimum 5-minute LULD halt for individual stocks and the possibility of delayed resumption · Differences in resumption methods by exchange
This is educational material for observation and information comprehension. Hypothetical examples do not represent actual stocks or performance and do not provide buy or sell recommendations.