What Is the Difference between ‘Last Look’ and ‘Pre-Trade Credit Check’ in Derivatives Trading?

'Pre-trade credit check' is a mandatory check performed before a quote is even sent or accepted to ensure the counterparty has sufficient collateral or credit limit to cover the potential trade. 'Last look' occurs after a quote has been accepted by the initiator but before final execution, allowing the quote provider a final chance to reject based on market conditions or risk.