41824 – Quantitative Easing: Unconventional Tools for Unprecedented Times

Quantitative easing (QE) has become an increasingly important monetary policy tool used by central banks worldwide to address economic challenges, especially in times of crisis. QE involves a central bank injecting liquidity into the financial system by purchasing assets, primarily government bonds, from commercial banks and other private institutions ¹. This expansionary approach differs from conventional open market operations, which typically adjust short-term interest rates to influence economic activity — QE is generally employed when interest rates are already low and further stimulus is needed ³. This entry examines the mechanics, objectives, and consequences of QE in detail, building on the introduction given in 41822.

This entry covers:

• The definition, mechanics, and intended macroeconomic impact of QE
• Its fiscal implications and the motivations that lead central banks to use it
• The transmission channels through which QE operates — signalling, liquidity, portfolio balance, and exchange rate
• Its risks and criticisms, and quantitative tightening (QT) as its reversal
• Historical examples from the Bank of Japan and the Federal Reserve

This entry does not cover:

• Central bank institutions and their broader function set → addressed in 41821
• Conventional monetary policy tools (interest rates, OMO, reserve requirements, forward guidance) → addressed in 41822
• The general dynamics, causes, and measurement of inflation and deflation → addressed in 41823
• Government fiscal policy in its own right, beyond QE’s fiscal-space implications → addressed in 41825

QE sits closer to the boundary between monetary and fiscal policy than the conventional tools covered in 41822, which is what makes its governance distinctive.

• The fiscal-monetary boundary: by lowering yields on government bonds, QE makes it cheaper for governments to borrow on financial markets ¹, giving governments more fiscal space for expansionary policy such as increased spending or tax cuts. This interplay between monetary and fiscal policy is central to how QE is scrutinised — large-scale central bank purchases of government debt raise the question of where independent monetary policy ends and government debt financing begins, the same fiscal-dominance concern raised in more general terms in 41821.
• Exit-strategy governance: unwinding QE through quantitative tightening is a recognised governance challenge in its own right — the process can generate market volatility and disrupt economic activity, and has been the subject of dedicated international policy research into the domestic and cross-border effects of central bank exit strategies ¹⁹.
• Distinct legal basis from conventional operations: because QE typically requires a central bank to purchase and hold much larger and broader pools of assets than routine open market operations, its use is generally reserved for periods where conventional tools are judged insufficient — the zero lower bound problem, deflationary pressure, or financial crisis — rather than treated as a routine instrument ^9,10.

Mechanics and intended impact. QE involves creating new bank reserves, used to purchase assets — primarily government bonds — from commercial banks and other financial institutions ⁵. This injection of liquidity aims to lower interest rates, encourage lending and investment, and stimulate economic activity ⁶, working partly by manipulating price signals: lowering interest rates, raising demand for assets, and reducing the purchasing power of money ⁷. Its intended effects are to lower interest rates ², increase liquidity by easing credit conditions ², boost asset prices (potentially generating a wealth effect) ⁵, and lower the domestic currency’s value to make exports more attractive ⁸.

Motivations. Central banks resort to QE when conventional tools are insufficient. Key motivations include: addressing the zero lower bound problem, where near-zero rates leave conventional tools with little room to manoeuvre ^9,10; combating deflation by increasing the money supply and encouraging spending ¹; responding to financial crises by stabilising markets, restoring confidence, and preventing a credit crunch ¹; and alleviating economic underperformance more generally, boosting activity during sluggish growth or recession ⁸.

Transmission channels. QE operates through several channels: the signalling channel, where the purchases themselves signal continued accommodative policy, boosting confidence and lowering long-term rates ^1,11; the liquidity channel, increasing liquidity in the financial system to ease bank lending and credit access ^1,2; the portfolio balance channel, shifting investor portfolios toward riskier assets as safe-asset supply falls ^12,13; and the exchange rate channel, depreciating the domestic currency to make exports more competitive and imports more expensive ^1,14.

Risks and criticisms. QE is not without downside. It carries inflationary risk if the economy is already near full capacity, though the actual inflationary effect depends on whether banks lend out the new liquidity rather than holding it as excess reserves ^2,15. It can inflate asset bubbles by driving up asset prices ¹⁶, exacerbate income and wealth inequality by disproportionately benefiting asset holders ¹⁷, and create moral hazard by encouraging risk-taking on the assumption the central bank will intervene again ¹⁸. Unwinding QE presents its own exit-strategy challenges ¹⁹, competitive currency devaluation between countries can unsettle the global economy (“currency wars”) ²⁰, and as a large-scale emergency measure, QE can prioritise short-term growth at the expense of long-term financial stability ²¹.

Quantitative tightening. QT reverses the process — the central bank sells previously purchased assets to reduce its balance sheet, aiming to shrink the money supply, raise rates, and curb inflation once the economy has recovered and policy can be normalised ¹.

Historical examples. The Bank of Japan (BOJ) was the first major central bank to implement QE, in the early 2000s, to combat deflation — targeting current account balances held at the central bank and purchasing assets such as government bonds ^1,22. While QE helped stabilise the Japanese economy, it did not fully achieve its inflation target, and Japan has faced ongoing challenges stimulating real economic growth despite extensive QE measures, suggesting the tool has limits in certain contexts ²³. The Federal Reserve implemented several QE programs in response to the 2007–2008 financial crisis and the COVID-19 pandemic, involving large-scale purchases of Treasury securities and mortgage-backed securities to stabilise financial markets and support recovery ^24,25.

1. Quantitative Easing — Bank of England
2. The Fed’s New Monetary Policy Tools — Federal Reserve Bank of St. Louis
3. Unconventional Monetary Policy — Reserve Bank of Australia
4. Quantitative Easing (QE) — Britannica Money
5. Quantitative Easing: How Does it Affect the Markets? — CMC Markets
6. The Financial Market Impact of Quantitative Easing — Bank of England
7. How Do Quantitative Easing and Tightening Affect Asset Prices? — Bank for International Settlements
8. Macroeconomic and Fiscal Consequences of Quantitative Easing — International Monetary Fund
9. Fed Communication and the Zero Lower Bound — Federal Reserve Bank of San Francisco
10. Monetary Policy, Financial Stability, and the Zero Lower Bound — Federal Reserve Board
11. Quantitative Easing in the Euro Area: Transmission Channels and Risks — Intereconomics
12. Portfolio rebalancing and the transmission of large-scale asset programmes — European Central Bank
13. The Portfolio Balance Channel of Quantitative Easing — Danmarks Nationalbank
14. Quantitative easing policies and exchange rates — CEPR
15. What’s Up? Quantitative Easing and Inflation — Research Affiliates
16. Quantitative Easing and Asset Bubbles in a Stock-flow Consistent Framework — Levy Economics Institute
17. Did the Fed’s quantitative easing make inequality worse? — Brookings Institution
18. Understanding the Effects of Quantitative Easing — YIP Institute
19. Central Bank Exit Strategies: Domestic Transmission and International Spillovers — IMF
20. Esprit de Currency: The Risks of Competitive Devaluation — International Monetary Fund
21. What Is Quantitative Easing? Advantages and Disadvantages — MasterClass
22. Monetary Policy in a Deflationary Environment — IMF eLibrary (Japan’s Lost Decade)
23. Quantitative Easing: A Rationale and Some Evidence from Japan — National Bureau of Economic Research
24. How the Federal Reserve’s Quantitative Easing Affects the Federal Budget — Congressional Budget Office
25. Federal Reserve: Tapering of Asset Purchases — Congressional Research Service