LUDSVolatility Trading Pause — Straddle Condition
LUDS is the sibling of LUDP. It fires when the LULD bands straddle the National Best Bid and Offer — the band boundary sits inside the spread rather than outside it — and the exchange determines that continuing to quote would be disorderly. A trader treats it much like a volatility pause, but it signals a thinner, more disjointed book than a standard LUDP.
What triggers it
- The LULD price band moves through the NBBO so that the band straddles the quote rather than bounding it.
- Usually seen where the book is thin and the quote is jumping in large increments relative to the band width.
How long it lasts
Five minutes, matching the standard LULD pause, with the same possibility of extension if the reopening auction cannot price inside the bands.
How it resumes
Reopens by auction on the primary listing exchange, the same mechanism used for LUDP.
What it means for a day trader
A LUDS print is a liquidity warning. The straddle condition implies the book was too thin to hold a two-sided market at the band.
Expect wider reopening spreads than a comparable LUDP on the same symbol.
Related halt codes
Track LUDS halts as they happen
Halt Strategy monitors live NASDAQ and NYSE halts, replays the setup around each event, and backtests outcomes segmented by halt code — so LUDS events are never averaged in with everything else.
Primary sources
Halt Strategy is research software, not investment advice, and does not execute trades. Halt procedures are set by the exchanges and regulators and can change; confirm current rules against the primary sources before acting on them. Read the full disclaimer and editorial policy.