Overnight Index Swaps
An Overnight Indexed Swap (OIS) is a fixed/floating interest rate swap with the floating leg tied to a published index of a daily overnight rate reference.
The term ranges from one week to two years (sometimes more). The two parties agree to exchange at maturity, on the agreed notional amount, the difference between interest accrued at the agreed fixed rate and interest accrued through geometric averaging of the floating index rate.