Macroeconomics
Interest Rates
Price of borrowed money — central macroeconomic variable
Interest rate is the price of borrowing money — what borrowers pay lenders. Many types: nominal vs real (real adjusts for inflation), short-term vs long-term, risk-free vs risky. Set by: market forces, central bank policy, risk perception. Effects throughout economy: investment, consumption, exchange rates, asset prices. Higher rates: borrowing more expensive; spending/investment decreases. Lower: stimulates. Federal Reserve targets federal funds rate. Yield curve: rates at different maturities; shape predicts recessions. Compound interest: interest on interest grows wealth.
- DefinitionCost of borrowing money
- Many typesShort-term, long-term, real, nominal, risk-free
- Central bank toolFed funds rate (US)
- Real interest rateNominal - inflation
- Yield curveRates at different maturities
- Inverted curveLong < short — recession indicator
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Why interest rates matter
- Personal finance. Borrowing, saving, investing.
- Business investment. Cost of capital.
- Housing market. Mortgage rates.
- Stock market. Discount rate for valuations.
- Bond market. Bond prices inverse to rates.
- International capital flows. Currency effects.
- Macro analysis. Central indicator.
Common misconceptions
- Fed sets all rates. Sets fed funds; influences others.
- Lower rates always better. Trade-offs (asset bubbles, savings).
- Same rate for all. Risk, time, type matter.
- Real and nominal same. Different in inflation.
- Yield curve always inverts before recession. Strong but imperfect.
- Just for borrowing. Affects asset prices broadly.
Frequently asked questions
What's an interest rate?
Price of borrowed money. Lender receives; borrower pays. Determined by: supply and demand for money/credit, risk, time preferences, monetary policy. Fundamental price in economy. Affects: borrowing, lending, consumption, investment, asset prices. Many different rates for different situations.
What's real vs nominal?
Nominal: stated rate (what's quoted). Real: inflation-adjusted. Real ≈ Nominal - inflation. Example: 5% nominal rate, 3% inflation → 2% real. Real matters for: actual purchasing power. Negative real rates (nominal below inflation): borrowers gain, savers lose. Common during high inflation (2022-2023) when nominal rates lagged inflation.
How does the Fed influence rates?
Federal funds rate: target. Achieved via: open market operations (buying/selling government bonds), discount rate (rate banks borrow from Fed). Federal funds rate: floor for short-term rates. Spreads to long-term rates indirectly. Doesn't directly set: mortgage rates, credit card rates, etc. — these driven by market forces influenced by Fed.
What's the yield curve?
Plot of interest rates against maturity. Normal: upward-sloping (longer maturity, higher rate; compensation for time, risk). Inverted: short-term rates higher than long-term (unusual; concerning). Flat: similar rates. Inverted curves: have predicted recessions for decades. Shape watched closely as economic indicator.
What's the inverted yield curve?
When short-term rates exceed long-term. Historically: precedes recessions. Logic: investors expect rates to fall (recession → Fed cuts) → buy long-term bonds → lower long rates. Reflects expected future economic weakness. Strong but imperfect indicator. Recent: inverted in 2022-2023; recession expected but slow to materialize.
What's compound interest?
Interest on interest. Initial principal grows; interest added; subsequent interest on larger balance. Powerful long-term. Example: $1000 at 5% annual compound interest. Year 1: $50. Year 2: $52.50 (5% of $1050). After 30 years: $4322. Simple interest (no compounding): $2500 only. Foundation of long-term wealth, retirement planning.
How do they affect housing?
Major impact. Mortgage rates closely tied. Higher rates: monthly payments increase; less buying power; demand decreases. Lower: opposite. 2022-2023: Fed raised rates rapidly; mortgage rates went from ~3% to ~7%; housing market slowed. Long-term: rates affect home prices, mortgage terms, investment in real estate.