Central Banking and Monetary Policy Glossary: Rates, Reserves, Repos and QE

Central banks influence financial conditions through their policy-rate decisions and the monetary and liquidity arrangements supporting payments and market functioning. Reserve balances, repo facilities and bond purchases are related but distinct mechanisms.

This monetary policy glossary explains operational terms frequently found in Bank of England, Federal Reserve and ECB publications. Because frameworks differ by jurisdiction and change over time, a definition must be paired with the relevant institution and date.

Why this specialist terminology matters

Market commentary often compresses a complex mechanism into one familiar expression. The right question is not only what a term means, but which contract, accounting basis, measurement date or operational framework applies. A number without this context can be precise and still misleading. The definitions below include both the basic concept and a caution about practical interpretation.

Central Banking and Monetary Policy Glossary: essential terms

Policy rate

The central-bank rate or target range used as a principal monetary policy instrument under a specific operating system. The market price of longer-term borrowing is not the same as today’s policy rate; expectations of future policy and risk premia matter.

Bank Rate

The Bank of England’s principal policy rate, which affects remuneration on eligible central-bank reserve balances and wider sterling market rates. It is not identical to a household mortgage rate or a gilt yield, both of which include other costs and expectations.

Monetary Policy Committee (MPC)

The Bank of England committee responsible for setting UK monetary policy to meet its statutory objectives. Its decision and the reasoning behind it should be distinguished from market expectations priced before the announcement.

Federal Open Market Committee (FOMC)

The US Federal Reserve committee that sets the stance of US monetary policy, including its policy-rate target range. Statements, forecasts and meeting minutes have different roles; an individual policymaker’s remarks are not a committee decision.

Deposit facility rate

A rate paid on qualifying overnight deposits held at a central bank under its operating arrangements, particularly relevant in the euro area. It can anchor short-term market rates but not eliminate every spread from credit, liquidity and collateral conditions.

Central-bank reserves

Electronic balances held by eligible commercial banks and certain institutions at a central bank, used for interbank settlement and policy operations. Reserves are not physical notes, household bank deposits or automatically spendable by the public. They are central-bank liabilities to eligible holders.

Commercial bank deposits

Liabilities owed by commercial banks to their customers, commonly used for payments and savings. A customer deposit is not itself an account at the central bank. Deposit creation, reserve settlement and bank capital requirements are different concepts.

Open market operation

An official transaction, such as an eligible asset purchase, sale or repo, used to influence market liquidity or implement monetary policy. Its effect depends on instrument, maturity, collateral, settlement arrangements and broader operating framework.

Repurchase agreement (repo)

A transaction in which securities are sold with an agreement to repurchase them on specified terms, economically resembling secured borrowing. Collateral quality, haircuts, maturity and counterparty exposures matter. Repo rates need not equal the central bank’s principal policy rate.

Reverse repo

The reverse side of a repo from the perspective of the party providing cash and receiving securities as collateral. The label depends on viewpoint; the same transaction is a repo for one party and a reverse repo for the other.

Standing facility

A central-bank facility available to eligible counterparties under defined conditions, sometimes used to provide or absorb overnight liquidity. Eligibility, collateral and pricing rules matter. Facility access does not imply unlimited or unconditional funding.

Lender of last resort

The provision of liquidity under exceptional conditions to support financial stability, subject to relevant authority and policy constraints. Emergency liquidity support should not be confused with taxpayer guarantees of an institution’s solvency or all deposits.

Quantitative easing (QE)

Large-scale asset purchases, often of government bonds, intended to influence financial conditions when warranted by monetary policy objectives. QE changes central-bank assets and liabilities and may affect longer-term yields; the impact is not mechanically equivalent to a direct rise in consumer spending.

Quantitative tightening (QT)

A reduction in a central bank’s asset holdings or balance-sheet accommodation, through maturities, sales or other mechanisms. QT’s effects depend on reserve demand, market liquidity and implementation. It need not translate into an equal change in bond yields.

Asset purchase facility

An arrangement through which a central bank or related vehicle holds eligible assets purchased under specified programmes. The legal holder, funding arrangements and indemnities vary across jurisdictions and programmes.

Term premium

The part of a longer-maturity bond yield reflecting compensation associated with holding longer-term interest-rate exposure under a chosen model. It is estimated rather than directly observed. Model disagreement makes simplistic claims about how QE changes term premium unreliable.

Forward guidance

Communication concerning the central bank’s expected reaction function or possible future policy path under specified conditions. It is not an unconditional commitment that rates will follow one path regardless of incoming data.

Monetary transmission

The channels through which monetary conditions influence bank lending, market rates, currencies, wealth, economic demand and inflation. The effects occur with uncertain timing and strength. A policy decision can have different impacts under different financial conditions.

Neutral interest rate

An estimated real interest rate consistent with balanced economic conditions over a specified horizon under a model. It is not directly observable or stable, and different models produce different estimates.

Yield curve

The relationship between interest rates or yields and maturities for a set of comparable instruments. A curve can invert because of expectations, term premia and market conditions; no shape is a certain recession forecast.

Interbank market

The market in which banks and other eligible institutions borrow and lend funds or exchange liquidity under different instruments. Credit and collateral terms influence prices; a published overnight reference rate is a benchmark, not a universal borrowing rate.

Sterling Overnight Index Average (SONIA)

A benchmark measuring eligible overnight unsecured sterling wholesale transactions according to the Bank of England’s published methodology. SONIA is a market-based benchmark and differs conceptually from Bank Rate. Calculation conventions and compounding matter when it appears in contracts.

Worked example and interpretation

Suppose a fictional central bank unexpectedly increases its policy rate by 0.25 percentage points, while investors had anticipated no change. An overnight benchmark may move closer to the new policy setting, but a ten-year government yield need not increase by exactly 0.25 points. The long yield embeds expectations about many future short rates, term premia and market-specific factors. A credible policy tightening could even lower long yields if investors revise inflation expectations downward. This is why a release must be compared with expectations, accompanying guidance and market conditions, rather than interpreted as a one-for-one mechanical price signal.

Analytical extension: central-bank balance sheets and market pricing

Consider a simplified central-bank bond purchase. The central bank acquires an eligible government security from a seller through the banking system and credits reserves to the relevant commercial bank. The bank may credit the seller’s deposit account in turn. The central bank now holds an additional asset and has issued an additional reserve liability; the seller holds a different portfolio of claims. This accounting transaction does not mean every household receives new funds or that banks lend reserves directly to retail borrowers.

QT can reverse parts of the balance-sheet expansion as bonds mature or are sold, but its impact on yields depends on buyers’ demand, government issuance, reserve scarcity and expected future monetary policy. Some central banks are moving towards frameworks in which reserves are supplied through secured lending operations as asset purchase holdings decline. Consequently, reserve quantities and the central bank’s asset-purchase portfolio need not move in lockstep over every period.

Policy surprise example: A market might already price a 25-basis-point rate cut. If the committee cuts by exactly that amount while signalling fewer later reductions, short-term market rates could rise relative to the pre-announcement level. This would not imply that the official rate actually increased: the change is in the expected future path. A complete event analysis therefore separates the announcement, prior consensus, policy guidance, inflation forecast and bond-market term premium.

Terminology is jurisdiction-specific. UK Bank Rate, US target-range operating tools and euro-area deposit facilities are not identically configured. A liquidity facility intended to support settlement need not indicate a change in the desired inflation outlook. Record which committee made the decision, which counterparties can use the facility and whether the figure represents a market rate, a policy instrument or a model estimate before inferring a market effect.

Concept comparison

Applying the terms in a structured research process

First identify the exact exposure or decision being studied. Record the relevant market or institution, contract specification, valuation basis and observation date. Separate directly observed data from estimates and from judgements. If the research question concerns the future, state more than one possible scenario rather than implying that a past relationship must continue.

Second, translate the terminology into its economic consequences. Ask which party receives or pays cash, what changes if the quoted price moves, what financing or collateral may be required and which risk remains after any hedge or mitigation. Whenever figures are compared, match units, timing and direction before doing the arithmetic.

Third, explain what would make the conclusion unreliable. A market can become less liquid, an estimated coefficient can shift, operational rules can change and the available data can be incomplete. Checking these limitations is part of professional analysis, not a weakness in the explanation.

Common interpretation mistakes

• Confusing the central bank’s reserves with the money balance available to retail customers.
• Assuming a change in the policy rate moves every FX pair, bond maturity and stock index in one direction.
• Using an outdated operational description without checking current central-bank facilities and rules.

Frequently asked questions

Is Bank Rate the same as SONIA?

No. Bank Rate is the Bank of England policy rate; SONIA is a published benchmark based on eligible overnight unsecured wholesale sterling transactions.

Does QE always create consumer-price inflation?

No. QE may influence financing and spending through several uncertain channels. Outcomes depend on macroeconomic conditions, transmission and policy interactions.

Can long-term bond yields fall after a rate rise?

Yes. A surprise rate rise can alter expectations for future inflation and growth or future policy, which may outweigh the immediate short-rate change.

Related education

Explore How Central Bank Balance Sheets Work; Quantitative Easing vs Tightening; SONIA and SOFR Explained, the Trading Glossary or the complete Education Hub.

Sources and further reading

• Bank of England — Monetary Policy
• Bank of England — Quantitative Easing
• Bank of England — Glossary

Important notice: General financial education only, not personalised advice or a recommendation to buy, sell or hold any financial instrument. All numerical scenarios are hypothetical. Investments and derivatives may incur significant losses and applicable product terms determine actual outcomes.