## Interest Rate Swaps

An Interest Rate Swap (IRS) is an exchange of two streams of cash flow. One counterparty agrees to pay one cash stream and the other party agrees to pay another cash stream. Some examples of IRS are a fixed to floating IRS, a basis swap or a cross currency swap.

The fixed or floating rate is multiplied by a notional principal amount and an accrual factor given by the appropriate day count convention. When both legs are in the same currency, this notional amount is typically not exchanged between counterparties, but is used only for calculating the size of cashflows to be exchanged. When the legs are in different currencies, the respective notional amount are typically exchanged at the start and the end of the swap.

The most common interest rate swap is one where one counterparty A pays a fixed rate (the swap rate) to counterparty B, while receiving a floating rate indexed to a reference rate (such as LIBOR or EURIBOR). By market convention, the counterparty paying the fixed rate is called the "payer" (while receiving the floating rate), and the counterparty receiving the fixed rate is called the "receiver" (while paying the floating rate).

The fixed or floating rate is multiplied by a notional principal amount and an accrual factor given by the appropriate day count convention. When both legs are in the same currency, this notional amount is typically not exchanged between counterparties, but is used only for calculating the size of cashflows to be exchanged. When the legs are in different currencies, the respective notional amount are typically exchanged at the start and the end of the swap.

The most common interest rate swap is one where one counterparty A pays a fixed rate (the swap rate) to counterparty B, while receiving a floating rate indexed to a reference rate (such as LIBOR or EURIBOR). By market convention, the counterparty paying the fixed rate is called the "payer" (while receiving the floating rate), and the counterparty receiving the fixed rate is called the "receiver" (while paying the floating rate).