What Is Quantitative Easing (QE)?
Quantitative easing is an unconventional monetary policy in which a central bank purchases large quantities of longer-term securities, mainly government bonds and, in the U.S., mortgage-backed securities, using newly created bank reserves. It became a signature tool after the 2008 financial crisis, when the Federal Reserve had already cut short-term rates to zero and needed another way to ease.
The goal is to lower long-term interest rates, flood the banking system with liquidity, and push investors out of safe assets into lending and risk-taking. The reverse process, letting bonds mature or selling them to shrink the balance sheet, is called quantitative tightening (QT).
How It Works
When the central bank buys bonds at scale, it bids up their prices and pushes down their yields, since bond prices and yields move inversely. Lower long-term yields reduce mortgage rates and corporate borrowing costs, while sellers of the bonds reinvest the proceeds into other assets, lifting prices across markets, a mechanism known as the portfolio rebalancing effect.
QE also works through signaling: a central bank committed to buying billions of bonds per month is clearly not raising rates soon, which anchors expectations. Critics note that QE can inflate asset bubbles, widen wealth inequality, and prove difficult to unwind.
Example
Between 2008 and 2014, the Fed's balance sheet grew from under $1 trillion to about $4.5 trillion across three rounds of QE. During the 2020 pandemic response it expanded again, from roughly $4 trillion to nearly $9 trillion, at one point absorbing $120 billion of bonds per month, which helped drive the 10-year Treasury yield below 1%.
Why It Matters
QE reshaped modern investing: years of suppressed bond yields pushed capital into stocks, private equity, real estate, and venture capital in a search for yield. When QE gives way to QT, that tide reverses, and liquidity-sensitive assets often struggle.
For valuation work, QE matters because it compresses the risk-free rate at the heart of every DCF, mechanically lifting the present value of future cash flows. Understanding where the central bank's balance sheet is headed is now as important as tracking its rate decisions.
