The swap spread that is fixed using a spreadlock and then added to the prevailing benchmark Treasury bond yield to arrive at the fixed swap rate. More specifically, the fixed rate on a swap consists of two components: the underlying benchmark Treasury bond yield and the swap spread. A spreadlock is an over-the-counter agreement to fix the swap spread component of a future transaction that involves an interest rate swap at a specific time or within a specified period of time. At that time or within that period of time, the fixed swap rate is set at the prevailing benchmark Treasury bond yield plus the spreadlock rate.