Open Market Operations
Open market operations (OMO) are the purchase and sale of government securities—usually short-term government bonds—by a central bank in the open market. They are the most frequently used instrument of monetary policy in modern economies, by which the central bank adjusts the supply of bank reserves and thereby influences short-term interest rates.[1]
Definition
In an open market operation, the central bank buys or sells securities from or to banks and financial institutions. These transactions change the volume of reserves in the banking system, which in turn affects the interest rate at which banks lend to one another and, ultimately, a broad range of interest rates in the economy.[1]
Mechanism
| Operation | Mechanism | Effect |
|---|---|---|
| Purchase of securities | Central bank pays for securities, injecting reserves into the banking system. | Expansionary; lowers interest rates. |
| Sale of securities | Central bank receives payment, withdrawing reserves from the banking system. | Contractionary; raises interest rates. |
Advantages
Open market operations are preferred by many central banks because they are:
- Flexible — they can be conducted in any volume on a daily basis.
- Reversible — the effects can be offset by opposite operations.
- Precise — they allow fine-tuning of liquidity conditions.
- Non-disruptive — they do not require changes to reserve requirements or lending facilities.
Related instruments
Open market operations are complemented by other tools, including the Deposit Reserve Ratio and the Rediscount Rate. During periods when short-term interest rates reach the zero lower bound, central banks may employ unconventional open market operations, such as large-scale asset purchases (quantitative easing).[1]