An interest rate swap (IRS) in which the fixed-rate payments are increased over the term of the swap and up to its maturity date. For example, an interest rate swap may have its fixed rate increased on a specific date or a number of dates (fixings) over the life of the swap.

A step-up swap can also be viewed as an accreting swap where the notional principal amount successively increases according to a specified schedule (typically a small number of increases in that amount).