"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."
Explanation of how central banks buy and sell securities in the open market to manage the money supply.
"The central bank can either buy or sell government bonds (or other financial assets) in the open market or enter into a repo or secured lending transaction with a commercial bank."
"A frequent aim of open market operations is - aside from supplying commercial banks with liquidity and sometimes taking surplus liquidity from commercial banks - to influence the short-term interest rate."
"Open market operations have become less prominent since the global financial crisis... implying that they may conduct OMOs less frequently."
"A floor system (or system of ample reserves) is where there is abundant liquidity in the payments system, and central banks no longer need to fine-tune the supply of reserves to meet demand."
"Direct intervention in the foreign exchange market, which is a specific type of open market operation, may be an important tool to maintain the desired exchange rate."
"Quantitative easing (QE) programs are technically similar open-market operations but entail a pre-commitment of the central bank to conduct purchases to a predefined large volume and for a predefined period of time."
"Under QE, central banks typically purchase riskier and longer-term securities such as long maturity sovereign bonds and even corporate bonds." Note: The above paragraph contains limited direct quotes and mostly provides explanations and general information. It may not be possible to directly quote every answer from the paragraph.