How is per-diem interest calculated if a gap closing lasts several days before final closing?

Per diem interest during a gap closing generally compensates the seller for the additional days between the practical closing, when funds and possession actually change hands, and the day registration is finally completed, since the seller is effectively still owed for that extra period even though the buyer has already taken over the property. It is typically calculated as a daily rate applied for each day the gap lasts, based on rate terms set out in the gap or escrow closing agreement itself.

The specific rate and method can vary from deal to deal, since it is a negotiated term of the arrangement rather than a fixed rule, so it should be spelled out clearly in whatever agreement your lawyer has your file operating under. If the gap turns out to be longer than originally expected, the total interest owed increases accordingly, which is one more reason lawyers try to keep gap closings as short as realistically possible rather than treating them as an open-ended solution. Ask your lawyer to walk you through exactly how the daily rate in your file was set before assuming a particular number.