An open market operation (OMO) is an activity by a central bank to give (or take) liquidity in its currency to (or from) a bank or a group of banks. The central bank can either buy or sell government bonds in the open market (this is where the name was historically derived from) or, in what is now mostly the preferred solution, enter into a repo or secured lending transaction with a commercial bank: the central bank gives the money as a deposit for a defined period and synchronously takes an eligible asset as collateral.