Last Look: The Brief Pause Behind a Fill

[Shadow Trader]

Last look is a practice where a liquidity provider keeps a short window after an order arrives, during which the order can be accepted or rejected against the provider's own current price. The window is usually measured in milliseconds, and its length varies by provider and by the terms agreed with the broker.

For scalpers, the relevance lies in asymmetry. If price moves in the taker's favour during the hold period, a rejection becomes more likely. If price moves against the taker, the fill tends to go through. Over many trades, this can skew execution quality toward the provider, even though each single rejection looks like routine noise.

Industry codes of conduct, such as the FX Global Code, say that last look should be used to verify validity and price, not to exploit information from the trade request. Providers are expected to disclose how it operates. Brokers passing through such liquidity may or may not explain it to clients.

Practical signals worth tracking include requote frequency, rejection messages, and variation in fill latency between winning and losing moves. Keeping a log of order timestamps and fill timestamps helps separate genuine market gaps from hold-time behaviour. A broker's execution policy is worth reading for terms such as last look or hold time.