Interest Rate

An interest rate is the price of money over time: what a borrower pays a lender, expressed as a percentage of the amount per year. Every rate in the economy decomposes into the same ingredients: compensation for waiting (time value), expected inflation, and a premium for the risk that repayment fails.

Key takeaways

• Interest rates price time, expected inflation and credit risk in one number.
• The real rate is the stated (nominal) rate minus inflation; it is what a saver actually earns in purchasing power.
• Central banks set a short-term policy rate; markets set all longer rates by trading bonds.
• When market rates rise, existing bond prices fall; the seesaw is mechanical.

One anchor, many rates

The Federal Reserve, ECB and their peers set an overnight policy rate. From that anchor, a structure of rates extends outward: government bond yields across maturities (the yield curve, see Treasury securities), then corporate borrowing at a credit spread above them, then mortgages, car loans and credit cards, each adding margins for risk and cost. A change at the anchor end transmits, with lags, through the entire chain, which is exactly why central-bank meetings dominate financial news.

Nominal versus real

A 5% savings rate during 7% inflation loses purchasing power; the real rate is about minus 2%. The distinction explains otherwise confusing history: US savers earning double-digit rates in 1980 were often worse off in real terms than savers earning 4% in calmer decades. Economists track expected real rates closely because they, not nominal headlines, describe the true tightness of money.

A brief sense of scale

Rates wander more than one financial lifetime suggests. US policy rates touched about 19% in 1981 fighting inflation, then spent 2009-2015 and 2020-2022 at essentially zero, with the 2022-2023 hiking cycle the fastest since the 1980s. Multi-century datasets (the Bank of England's spans 1694 onward) show long swings spanning generations, a useful antidote to treating any recent level as normal.

Frequently asked questions

Why do central banks change rates at all?

Raising rates cools borrowing, spending and eventually inflation; cutting does the reverse for weak economies. It is the main lever described under Federal Reserve.

What is APR versus APY?

APR states the simple annual rate; APY (or effective annual rate) includes compounding within the year, as explained under compound interest. Disclosure rules exist precisely so borrowers can compare like with like.

Sources

• Federal Reserve, Policy rates and monetary policy
• Bank of England, A millennium of macroeconomic data
• Consumer Financial Protection Bureau, APR explained