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What Is Quantitative Easing and Why Do Central Banks Use It?

Quantitative easing (QE) is a monetary policy tool in which a central bank purchases large quantities of long-term securities—primarily government bonds and mortgage-backed securities—to inject money directly into the economy when traditional policy tools have reached their limits. Unlike open market operations, which typically involve short-term Treasury bills traded daily, quantitative easing involves large-scale purchases of longer-term securities designed to influence long-term interest rates and increase the money supply simultaneously. Central banks resort to quantitative easing when they have already lowered short-term interest rates to zero and need additional stimulus to support economic growth. Quantitative easing is therefore a policy of last resort, deployed during severe recessions or financial crises when the economy needs emergency support. Understanding quantitative easing is essential because it affects asset prices, inflation expectations, and the distribution of wealth in ways that traditional interest rate policy does not.

Quantitative easing is a monetary policy tool where a central bank purchases large quantities of long-term securities to inject money into the economy and lower long-term interest rates when short-term rates are already near zero.

Key Takeaways​

  • Quantitative easing is deployed when the federal funds rate is already at zero and further stimulus is needed
  • The Fed purchases long-term securities (Treasuries and mortgage-backed securities) on a large scale, injecting money into the banking system and increasing the money supply
  • QE works by influencing long-term interest rates, not short-term rates; the massive purchases reduce the supply of securities available to private investors, pushing down long-term yields
  • QE increases the Fed's balance sheet dramatically; the size of the Fed's balance sheet directly reflects the cumulative amount of securities purchased
  • Quantitative easing can have unintended consequences, including inflating asset prices, increasing income inequality, and potentially creating future inflation
  • The opposite of quantitative easing is quantitative tightening (QT), in which the Fed sells securities or allows them to mature without replacement, shrinking the money supply

Understanding the Zero Lower Bound Problem​

To understand why central banks use quantitative easing, we must first understand the problem it is designed to solve: the zero lower bound.

Normally, when the economy is weak and unemployment is high, the Federal Reserve lowers interest rates to encourage borrowing and spending. Lower rates make mortgages cheaper, car loans cheaper, and business loans cheaper. Consumers and businesses respond to cheaper credit by borrowing more, spending more, and investing more. The economy expands.

But there is a floor to interest rates. You cannot charge negative interest on overnight loans (in normal circumstances). If you lend a bank $100 overnight at -1%, the bank only has to repay you $99 the next day—a direct loss. No bank will accept this deal. Therefore, the federal funds rate cannot fall below zero.

This creates a problem when the economy is in severe distress. During the 2008 financial crisis, the Fed would have liked to lower the federal funds rate to -5% or lower to stimulate maximum borrowing. The Fed believed the economy needed enormous stimulus. But they could not push rates negative (practical and political constraints prevent it). With the federal funds rate at zero and the economy still weak, the Fed faced a constraint. Its primary policy tool was exhausted. This is the zero lower bound problem.

The Fed still had more ammunition. It could do quantitative easing.

How Quantitative Easing Works: The Mechanics​

Quantitative easing works through a different channel than open market operations. In open market operations, the Fed buys short-term Treasury bills—typically 1-6 month bills—creating a small ripple effect on short-term rates. In quantitative easing, the Fed buys long-term securities—10-year Treasury notes, 30-year Treasury bonds, and mortgage-backed securities (MBS).

The process begins with an FOMC decision. The committee states that it will conduct large-scale asset purchases. The Fed might announce: "The Federal Open Market Committee will purchase approximately $600 billion of longer-term Treasury securities and approximately $200 billion of mortgage-backed securities over the next six months."

The Fed's Open Market Desk then executes these purchases. Rather than buying from primary dealers like it does in normal open market operations, the Fed conducts larger purchases from various financial institutions. The Fed buys $10 billion of 10-year Treasury notes on Monday. On Tuesday, it buys $8 billion of 5-year notes and $5 billion of 30-year bonds and $2 billion of mortgage-backed securities. The purchases continue day by day according to the announced program.

When the Fed buys these securities, it pays for them by crediting the reserve accounts of the institutions that sell the securities. If Goldman Sachs sells a 10-year Treasury to the Fed for $1 billion, the Fed credits Goldman Sachs's reserve account with $1 billion. Goldman Sachs now holds an additional $1 billion in reserves instead of a Treasury bond.

The Fed's balance sheet expands. The Fed's assets increase by $1 billion (the newly purchased Treasury). The Fed's liabilities increase by $1 billion (the additional reserves credited to Goldman Sachs and other financial institutions).

The key to quantitative easing is that this process is repeated on a massive scale. In 2008-2009, the Fed purchased roughly $1.75 trillion in securities. In 2020, the Fed purchased roughly $2.5 trillion in securities in just a few months. These purchases create enormous amounts of new money in the form of bank reserves.

The Transmission Mechanism: How QE Affects Long-Term Rates​

Understanding how quantitative easing stimulates the economy requires understanding how it affects long-term interest rates.

Long-term interest rates (mortgage rates, corporate bond rates, Treasury yields) are determined by supply and demand in the market for long-term securities. When the Fed conducts quantitative easing, it removes long-term securities from the market by buying them. This reduces the supply of securities available to private investors.

Imagine a simplified market for 10-year Treasury bonds. Before the Fed's purchases, there are 1 million 10-year bonds in the market. Investors demand 800,000 of them at a 2% yield. The market clears with some bonds unsold, and the yield rises to 2.2% to attract additional demand.

Now the Fed purchases 200,000 of these 10-year bonds through quantitative easing. The supply of bonds available to private investors falls from 1 million to 800,000. Demand remains at 800,000. The market is now in equilibrium at the lower supply level. But investors who previously demanded bonds at 2.2% now find fewer bonds available. To acquire the bonds they want, they bid up prices, driving yields down to 1.8%.

This is the wealth effect and portfolio effect of quantitative easing. By removing securities from the market, the Fed pushes down yields on those securities. Investors looking for safe assets like Treasury bonds find them scarcer, so they buy them at higher prices (lower yields).

The transmission then works through several channels. First, lower long-term interest rates directly stimulate borrowing. A business calculating the returns from a 10-year investment project sees that the cost of financing has fallen from 2.2% to 1.8%. More projects are profitable at the lower rate. The business borrows and invests. Workers are hired. Economic activity increases.

Second, lower long-term rates support asset prices. Stocks are valued based on expected future profits discounted at the long-term interest rate. If the discount rate falls, stock valuations rise. Higher stock valuations increase household wealth. Wealthier households spend more. Economic demand increases.

Third, lower long-term rates affect expectations. When the Fed conducts large-scale asset purchases, it is signaling that policy will remain accommodative for an extended period. Investors revise upward their expectations for future growth and inflation. Forward guidance about the Fed's intended path for policy helps shape these expectations. Businesses become more optimistic and invest. Consumers become more confident and spend.

This is how quantitative easing, conducted in financial markets by the Fed buying and selling securities, ultimately affects unemployment, growth, and inflation in the real economy.

Quantitative Easing in Practice: The Three Rounds (2008-2015)​

The Federal Reserve deployed quantitative easing in three major programs following the 2008 financial crisis. Understanding these programs reveals how QE has been used in practice.

QE1 (November 2008-March 2010): The Fed announced that it would purchase approximately $600 billion in mortgage-backed securities and $100 billion in direct obligations of mortgage-sponsored enterprises. The Fed later expanded the program to include $300 billion in longer-term Treasury securities. Total purchases eventually reached approximately $1.75 trillion. The Fed's balance sheet expanded from $900 billion to roughly $2.3 trillion. These enormous purchases were designed to support the housing market and encourage lending as the financial system was collapsing. The Fed shifted from buying short-term Treasury bills to buying longer-term securities and mortgage-backed securities precisely because the federal funds rate was already at zero.

QE2 (November 2010-June 2011): After a brief pause, the economy remained weak and unemployment was still above 9%. The Fed announced QE2, a program to purchase an additional $600 billion in longer-term Treasury securities over an eight-month period. The Fed's balance sheet expanded further. The stated objective was to provide additional support to economic recovery and further lower long-term interest rates. Critics argued that the economy was already recovering and that additional asset purchases risked inflating asset bubbles. The Fed proceeded anyway, believing additional accommodation was warranted given persistent unemployment.

QE3 (September 2012-December 2014): By 2012, the economy was growing but unemployment remained above 8%. The Fed announced QE3, a program of potentially unlimited purchases of mortgage-backed securities. Unlike QE1 and QE2, which were time-limited and quantity-limited, QE3 continued until conditions improved sufficiently. The Fed committed to purchasing MBS at a rate of $40 billion per month. In September 2012, the Fed expanded the program to include purchases of longer-term Treasuries as well. The program continued for over two years, with the Fed eventually purchasing trillions in additional securities. The Fed's balance sheet peaked at around $4.5 trillion in 2015.

These three rounds of quantitative easing succeeded in lowering long-term interest rates significantly. When QE1 began in November 2008, the 10-year Treasury yield was approximately 3.7%. By the end of QE3 in 2014, the yield had fallen to approximately 2.2%. Mortgage rates fell from approximately 6.5% to below 3%. These lower rates did support housing recovery and helped restore credit markets. By 2015, unemployment had fallen to below 5% and the economy was expanding. The Fed began reversing course, raising the federal funds rate and eventually shrinking the balance sheet.

The Fed's Balance Sheet: Reading the Effects of QE​

The Federal Reserve's balance sheet is public information published weekly on the Federal Reserve's website. By understanding how to read the balance sheet, you can see directly the results of quantitative easing.

The Fed's assets include primarily Treasury securities and mortgage-backed securities. When the Fed conducts quantitative easing, these asset holdings increase. In November 2008, the Fed held approximately $600 billion in Treasury securities and $100 billion in mortgage-backed securities. By the end of 2014, the Fed held approximately $2.5 trillion in Treasury securities and $1.8 trillion in mortgage-backed securities. The increase directly reflects the three rounds of quantitative easing.

The Fed's liabilities include bank reserves and currency in circulation. When the Fed buys securities, it credits bank reserves, increasing this liability. The 2008-2015 quantitative easing programs increased bank reserves from less than $50 billion to over $2.5 trillion. This increase represents the new money created through quantitative easing.

One important detail: the Fed's assets and liabilities must balance (this is basic accounting). When the Fed buys $1 trillion in Treasury securities (an asset), it credits bank reserves of $1 trillion (a liability). Both sides of the balance sheet expand by equal amounts. This is why quantitative easing is sometimes described as "creating money out of thin air"—the Fed creates liabilities (bank reserves) that constitute money, and balances them with assets (securities).

During 2022-2023, the Fed began quantitative tightening (QT)—the reverse of QE. As the Fed raised interest rates to fight inflation, it stopped purchasing securities and allowed previously purchased securities to mature without replacement. As securities matured, the Fed received principal payments and did not reinvest them. The Fed's balance sheet shrank from a peak of approximately $8.9 trillion in 2022 to approximately $7.8 trillion by late 2023. This shrinkage represents money being removed from the system.

Real-World Examples of Quantitative Easing Effects​

The 2008-2009 Crisis and QE1: When the Fed began QE1, credit markets had frozen. Banks were not lending. The Fed's goal was to support the financial system and prevent total collapse. The massive purchases of Treasury securities and mortgage-backed securities signaled that the Fed would use all its tools to prevent catastrophe. The purchases directly supported mortgage-backed securities prices, preventing a complete collapse in MBS values. Banks that held these securities could see the prices more stable. Credit gradually thawed. By 2010, credit was flowing again, though slowly. Unemployment peaked at 10% in October 2009 but eventually fell. Many economists believe that without QE1, the Great Recession would have become another Great Depression.

QE2 and Asset Price Inflation: QE2 occurred in a period when some economic recovery was already underway. Critics of QE2 argued that the Fed was overheating the economy and inflating asset prices unnecessarily. Stock prices indeed rose sharply during QE2, with the S&P 500 rising from roughly 1,000 in August 2010 to 1,300 by June 2011. Real estate prices also recovered faster than they might have without the Fed's support. Some observers worry that QE2 laid the groundwork for the 2010s real estate and stock market bubbles by keeping interest rates too low for too long.

QE3 and Long-Term Effects: QE3 continued for over two years with no end date announced, signaling the Fed's commitment to support the recovery indefinitely if necessary. This open-ended commitment was controversial. Critics argued that it created moral hazard—financial institutions knew the Fed would support asset prices if markets fell, so they took more risk. Others argued that it was necessary to ensure a robust recovery after the near-depression of 2008-2009. Empirically, unemployment fell and growth eventually accelerated. Asset prices rose substantially during QE3. By 2015, stock prices were at all-time highs, unemployment was below 5%, and the Fed felt comfortable raising rates.

Pandemic QE (2020): The Fastest Buildup of Balance Sheet Ever: When COVID-19 lockdowns began in March 2020, markets panicked. The Fed responded with unprecedented speed and scale. In the first week of March 2020, the Fed cut the federal funds rate to zero. In the second week, it announced massive open market operations. In the third week, it announced that it would purchase "unlimited" amounts of Treasury securities and mortgage-backed securities. By the end of April 2020, the Fed had purchased approximately $2.5 trillion in securities (the same amount as the entire QE1+QE2+QE3 programs combined). The Fed's balance sheet expanded from approximately $4.3 trillion in February 2020 to approximately $7.4 trillion by May 2020. This rapid expansion was necessary to prevent financial markets from seizing up during the acute panic.

The Criticisms and Risks of Quantitative Easing​

Quantitative easing has become increasingly controversial as it has been used more frequently and on larger scales. Several criticisms deserve serious consideration.

Inflation risk: By expanding the money supply dramatically through QE, the Fed increases the risk of future inflation. If the Fed purchases $2 trillion in securities and money supply doubles, but the economy's productive capacity grows only 2-3%, the excess money will chase scarce goods and drive prices up. This is precisely what happened in 2021-2022. The Fed conducted massive QE in 2020, expanding the money supply by over 40%. When supply chains were constrained and production could not keep pace, inflation surged to 9.1% in June 2022. Some economists blame the Fed's excessive QE for the inflation problem.

Asset price inflation: QE tends to inflate asset prices (stocks, real estate, commodities) more than consumer prices initially. By lowering interest rates, the Fed makes safe assets less attractive, pushing investors into riskier assets seeking higher returns. Stock valuations expand. Real estate prices rise. If these price increases exceed the growth in fundamental values, bubbles can form. The 2010s saw record-high price-to-earnings ratios in stocks and unprecedented real estate prices in major cities. When bubbles burst, the consequences can be severe.

Income inequality: QE benefits asset owners disproportionately. Wealthy households own stocks and real estate; lower-income households hold cash. When QE inflates asset prices, the wealthy benefit enormously. Lower-income households see the purchasing power of their cash savings eroded as inflation rises. The wealth gap expands. This distributional impact is controversial and politically divisive.

Moral hazard: When the Fed conducts QE to support the economy during crises, it creates an expectation that the Fed will always intervene during crises. This reduces the incentive for financial institutions to manage risk carefully. Why reduce risky lending if the Fed will rescue the system if losses occur? The 2008 crisis was partly caused by excessive risk-taking enabled by the belief that "the Fed will not let anything fail." QE reinforces this belief, potentially setting up future crises.

Effectiveness at the margin: Early QE in 2008-2009 was highly effective because credit had frozen and financial panic was acute. The Fed's actions directly addressed this emergency. Later QE programs, conducted when conditions were less dire, were less effective. QE2 occurred with the economy already growing; its marginal impact was modest. Some economists question whether the last trillion dollars of QE purchases in 2013-2014 were worth the risks they created.

Quantitative Tightening: The Reverse of QE​

The opposite of quantitative easing is quantitative tightening (QT)—shrinking the Fed's balance sheet by allowing securities to mature without replacement or by actively selling securities.

Quantitative tightening removes money from the system. As the Fed's assets decline, bank reserves decline as well. The money supply contracts. Long-term interest rates tend to rise because the Fed is no longer purchasing securities to suppress yields.

The Fed began quantitative tightening in late 2022 as inflation remained elevated and the Fed was raising the federal funds rate. The Fed announced that it would allow up to $30 billion per month of Treasury securities and up to $17.5 billion per month of mortgage-backed securities to mature without replacement. As securities matured, the payments went directly to the Treasury and were not reinvested. The Fed's balance sheet shrank from approximately $8.9 trillion in 2022 to approximately $7.8 trillion by late 2023.

Quantitative tightening is contractionary—it reduces the money supply and puts upward pressure on long-term interest rates. The Fed used it as one tool among many to fight inflation. However, quantitative tightening must be conducted carefully. If the Fed shrinks the balance sheet too rapidly or if financial conditions deteriorate, a shortage of liquidity could develop. The 2023 banking crisis (with the failures of Silicon Valley Bank and Signature Bank) was at least partly attributed to rapid Fed tightening reducing liquidity and creating duration risk in bond portfolios.

Common Mistakes in Understanding Quantitative Easing​

Mistake 1: Confusing QE with printing money. Quantitative easing does not involve printing physical currency. It involves creating electronic bank reserves through large-scale purchases of securities. However, the economic effects are similar to currency printing—an increase in the monetary base and money supply. The psychological image of "printing money" is misleading but captures the essence of the policy.

Mistake 2: Thinking QE is permanent. Quantitative easing is typically intended as a temporary emergency measure. The Fed announces QE programs with intended duration and scale. When conditions improve, the Fed ends QE and eventually reverses it through QT. The massive QE of 2008-2014 eventually gave way to rate increases and QT in 2015-2018 and again starting in 2022. QE is not a permanent feature; it is cyclical.

Mistake 3: Assuming QE only affects financial markets. While QE does affect stock prices, bond yields, and other financial asset prices, its effects on the real economy are the ultimate concern. Lower long-term rates should support investment, hiring, and growth. Asset price inflation can lead to real inflation and redistribute wealth. QE's full effects encompass both financial markets and the real economy.

Mistake 4: Believing QE is the same as monetary policy. QE is one tool that the Fed uses, but it is not monetary policy as a whole. Monetary policy encompasses open market operations, interest rate decisions, reserve requirement changes, lending facility changes, and forward guidance. QE is specifically large-scale asset purchases designed to influence long-term rates when short-term rates are at zero. Traditional monetary policy operates through interest rate decisions. They are related but distinct.

Mistake 5: Assuming QE always works as intended. QE's effectiveness depends on economic conditions and financial market transmission. In a severe financial crisis with credit frozen, QE is very effective at restoring financial function. In a recession with credit already available, QE is less effective at stimulating demand. If the constraint is not credit availability but rather household or business confidence, QE may not work. The failure of negative interest rates and massive QE to stimulate Japanese growth in the 1990s-2000s is an example of QE's limitations.

Frequently Asked Questions​

How much money does quantitative easing actually create?​

Quantitative easing creates bank reserves equal to the value of securities purchased. If the Fed purchases $1 trillion in securities through QE, it creates approximately $1 trillion in bank reserves. This is new money in the banking system. However, this new money is not the same as currency in circulation. It is an electronic balance in a bank's account at the Fed. How much of this money translates into the broader money supply (M2) depends on how banks lend and how multipliers work. Empirically, the money multiplier has been lower than historically, so QE creates less money supply growth per dollar of Fed purchases than one might naively expect.

Why doesn't the Fed just buy stocks or real estate through QE instead of bonds?​

The Federal Reserve is technically restricted to purchasing "direct obligations of the Federal Government" and "obligations fully guaranteed as to principal and interest by the Federal Government" in normal circumstances. This means Treasury securities and mortgage-backed securities (which are implicitly backed by the government-sponsored enterprises Fannie Mae and Freddie Mac). The Fed lacks legal authority to purchase stocks directly. This restriction is intentional—it prevents the Fed from directly supporting particular companies or industries. During crises, the Fed has created special lending facilities that accept corporate bonds, but outright stock purchases remain off limits.

Could the Fed conduct QE indefinitely?​

Theoretically yes, but practically no. The Fed's balance sheet is already enormous (over $7 trillion). If the Fed kept purchasing securities indefinitely, eventually it would own most or all outstanding Treasury and mortgage-backed securities. At that point, the market for these securities would effectively disappear. The Fed would face operational challenges managing such an enormous portfolio. More importantly, unlimited QE would create so much inflation that the currency would lose value. At some point, the costs of continued QE (high inflation, financial instability, currency depreciation) exceed the benefits. The Fed therefore uses QE as a temporary tool, not a permanent feature.

How does QE affect savers?​

QE typically reduces interest rates, which is harmful to savers. If you hold a savings account earning 4%, QE that lowers rates to 0.25% means you earn much less interest. Your purchasing power erodes if inflation rises due to the QE. Savers are effectively taxed through reduced interest income and inflation. This is one reason QE is controversial—it helps borrowers and asset owners at the expense of savers and cash holders. Retired people living on interest income from savings accounts are particularly harmed by QE policies that target zero rates.

When will the Fed stop shrinking its balance sheet?​

This depends on Fed policy decisions, which are uncertain. The Fed typically shrinks the balance sheet when it is raising interest rates to fight inflation or when it believes rates should be higher. As of 2024, the Fed is expected to eventually stabilize the balance sheet at a larger size than pre-2008 (roughly $5-6 trillion instead of $900 billion), reflecting structural changes in financial system demand for reserves. The exact timing and size remain to be determined by future Fed decisions.

Quantitative easing operates within a broader monetary policy framework. Understanding QE fully requires knowledge of related tools and objectives:

Summary​

Quantitative easing is a monetary policy tool in which central banks purchase large quantities of long-term securities to inject money into the economy and lower long-term interest rates when traditional policy (lowering short-term rates) is no longer effective. The Fed typically deploys QE when the federal funds rate is already at zero and the economy still requires stimulus. Quantitative easing works by removing long-term securities from private markets, pushing down long-term yields and making risky assets more attractive. The Fed deployed three major rounds of QE from 2008-2014, expanding the balance sheet from approximately $900 billion to over $4 trillion. These programs successfully supported credit markets during the financial crisis and contributed to economic recovery. However, QE also risks inflating asset prices, increasing income inequality, and creating future inflation if not managed carefully. More recently, the Fed deployed emergency QE in 2020 to support the pandemic-shocked economy, followed by quantitative tightening beginning in 2022 to combat inflation. Understanding quantitative easing is essential for understanding how modern central banks manage crises and attempt to steer economies toward growth with stable inflation.

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