New momentum traders treat halts as something that happens to them. Experienced ones treat the halt code as the single highest-information field on the screen, because it tells you why the tape stopped and roughly what happens next.
The codes you will actually see
| Code | Meaning | Typical duration | What it implies |
|---|---|---|---|
| LUDP | Limit Up, Limit Down volatility pause | 5 min | Price moved outside the band and stayed there. Mechanical, not informational. |
| T1 | News pending | 30 to 60 min | The company has told the exchange something is coming. The reopen prices new information. |
| T2 | News released | Short | Dissemination has happened. The market is being given time to read it. |
| T12 | Additional information requested | Hours to days | The exchange has asked a question. This is the one that can keep you locked in. |
| H10 | Regulatory concern | Extended | Serious. Do not plan on trading the reopen. |
The reopening auction
Nasdaq reopens a halted stock through an auction, not by simply resuming continuous trading. There is a quotation period where orders accumulate and indicative prices publish, then a single cross print. Everything after that print is normal trading again.
Two things follow from this. First, the indicative price during the quotation period is real information and it moves. Watching it is how you form a view before the cross. Second, the cross itself is a genuine liquidity event, often the largest single print of the session, and it is frequently the high or low of the move.
A LUDP pause on a nano float most often reopens near where it paused and continues. A T1 reopen is a repricing and can gap in either direction regardless of which way the halt came in.
Decide before, not during
- ·Write your behaviour for a halt into the plan, before the open, per position.
- ·Know whether your broker lets you cancel and place orders during the quotation period. Many restrict order types.
- ·Treat the indicative price as a live estimate that will move, not a promise.
- ·On a name with no borrow, understand you may not be able to hedge or exit at the cross.