What is open market operations
Open market operations (OMOs) are a central bank buying or selling government securities with banks to add money to, or remove money from, the banking system.
When the central bank buys securities, banks receive cash, and short-term interest rates tend to fall. When it sells securities, banks pay cash, and short-term rates tend to rise.
- The central bank buys government bonds with newly created money (QE).
- Bond yields fall and there is more money in the system.
- Holding the currency pays less than before.
- The currency tends to weaken; ending QE (tapering) usually works the other way.
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OMO meaning: the formal definition
Formally, OMOs are the central bank's discretionary transactions in eligible securities that manage liquidity, meaning the cash banks hold to settle payments and meet reserve needs. Their purpose is to keep the overnight interbank rate close to the policy rate.
OMOs come in two forms:
- Outright operations. The central bank buys or sells securities permanently. This changes liquidity for a long time.
- Repo-based operations. The central bank lends cash against securities as collateral for a set term (an injection), or borrows cash against securities (a mop-up). At the end of the term, the deal reverses. Most routine OMOs use this form.
OMO at the State Bank of Pakistan
The State Bank of Pakistan (SBP) sets a policy rate and an interest rate corridor. The corridor has a ceiling rate, at which banks can borrow from the SBP overnight, and a floor rate, at which they can place spare cash with it. OMOs keep the overnight rate inside that corridor and near the policy rate. The latest decision recorded on this site: SBP policy rate raised by 50 bps to 12% with effect from 27.10.2026 (MPC).
The SBP announces OMO results with the amount offered, the amount accepted and the rate. Under Islamic banking, it also runs Shariah-compliant operations based on sukuk. See Islamic finance.
Worked example (hypothetical)
Suppose tax payments drain cash from banks before a quarter ends. Banks run short, and the overnight rate rises above the policy rate and moves towards the ceiling.
- The central bank announces a reverse repo injection. It lends cash to banks against treasury bills.
- Banks bid. The central bank accepts bids up to the amount it judges the system needs.
- Liquidity rises, and the overnight rate moves back towards the policy rate.
- At maturity, banks repay the cash and get their bills back. The extra liquidity is withdrawn unless the central bank rolls the operation over.
If banks instead hold surplus cash and the overnight rate falls towards the floor, the central bank does the opposite. It runs a mop-up and absorbs the cash.
Where you see the term
- Central bank releases: OMO injection or mop-up results, and monetary policy statements.
- Financial news: headlines about "record OMO injections" or a liquidity shortage in the banking system.
- Economic calendars in trading platforms and news terminals: policy rate decisions, which OMOs then support.
Edge cases experienced readers should know
- OMO vs policy rate change. OMOs carry out the rate the central bank has already set. A large OMO is not a rate cut by itself.
- OMO vs quantitative easing. QE is a large outright buying programme aimed at longer-term yields. Routine OMOs target overnight rates.
- OMO vs FX intervention. Buying or selling foreign currency also changes rupee liquidity. Central banks often offset that effect with OMOs. This offset is called sterilisation.
- Persistent large injections can mean that banks depend on central bank funding. Analysts watch this as a stress signal.
For a trader, OMOs are background information for fundamental analysis, not a signal. Leveraged forex and CFD trading can lose money fast, whatever the rate setting.
Related terms
- Basis point
- Bond auction
- Coupon (bond)
- Face value (par value)
- Fractional reserve banking
- Credit crunch
- Currency depreciation
- Trading glossary
Frequent questions
What does OMO mean?
OMO stands for open market operation. It means a central bank buys or sells securities, or runs repos, to manage bank liquidity.
What is an OMO injection by the State Bank of Pakistan?
It is a reverse repo in which the SBP lends cash to banks against government securities for a set term. It adds liquidity to the banking system.
What is an OMO mop-up?
It is the opposite of an injection. The central bank absorbs surplus cash from banks, which pushes short-term rates up towards the policy rate.
Do OMOs move the rupee exchange rate?
Not directly. They affect short-term interest rates, and the exchange rate depends on many other factors as well.