What is a yield curve?
- A yield curve maps bond interest rates against their maturities.
- Its shape reflects market expectations for growth and inflation.
- A normal curve slopes up with longer maturities.
- A flat curve shows little gap between short and long rates.
- Inversion, short rates above long rates, has preceded recessions.
What is a yield curve?
A yield curve is a graph plotting the interest rate that bonds of equal credit quality pay against their maturity dates, from months to thirty years. Its line summarizes what the market expects for the economy ahead.
The most watched is the Treasury curve, because the US government's bonds set the baseline for everything else. Its line is a single summary of what the entire market believes about the economy's future.
What shapes can the curve take?
A normal curve slopes upward, with longer-term bonds paying more than short-term ones. That is the everyday shape, rewarding you for locking money up longer. A flat curve carries little gap between short and long rates, often a sign of uncertainty.
An inverted curve slopes downward, with short-term yields higher than long-term ones. A steep curve, in contrast, says the market expects faster growth and higher inflation ahead, so it demands more yield for tying up long-term money. Inversion is the shape that gets everyone talking.
What drives the shape of the curve?
Two forces shape it: the term premium and the inflation premium. The term premium is the extra yield you demand for locking money up longer, and the inflation premium is the cushion you need because inflation erodes a long-term promise of fixed payments. Both push the normal curve upward.
Before the line inverts, it often flattens and then humps. A humped curve dips in the middle when medium-term bonds pay less than bonds on either side, a sign that markets expect rates to fall. It is the shape the curve takes while it turns.
The Treasury curve is the benchmark, and its gap against riskier bonds is the credit spread. When investors fear a downturn, they demand far more to hold corporate bonds, so the spread widens. When confidence returns, the spread narrows again.
These forces move together, so the curve is never a single clean reason. Growth expectations, rate policy, and inflation all feed the same line. Reading it means watching the whole shape, not fixating on one point.
What does a steep or flat curve tell you?
A steep curve says investors expect economic expansion ahead and demand more compensation for the risk premium of long-term debt; it often appears early in recoveries. A flat curve says the market sees little gap between short and long rates, typically a sign of uncertainty or a transitioning economy.
Why is an inverted curve a recession warning?
An inversion happens when short-term rates sit above long-term ones, for example when the 2-year Treasury yields more than the 10-year. Since long rates reflect expectations, inversion says investors expect rates to fall, which usually precedes a downturn. The pattern has preceded most US recessions in modern decades.
It is not foolproof, and timing is imprecise. A recession can arrive months or years after an inversion appears, and not every one delivers a downturn. The longest modern inversion stretched 784 days before fading. Still, banks, fund managers, and central bankers track it as a top leading indicator.
How do you use the yield curve?
Watch the shape for an early read on the economy. An upward curve favors risk and growth; an inverted one is a caution flag pointing to safety. Do not trade the curve alone. Pair it with interest rates, earnings, and valuation, and let it tilt your posture.
What are the term structure theories?
The expectations hypothesis says every maturity is a perfect substitute. A long rate is just the market's guess at the average of future short rates. If you expect rates to rise, the curve slopes up; if you expect them to fall, it inverts.
Liquidity preference theory refines that. Investors prefer short bonds, so they demand a premium to hold longer ones. That term premium is why long rates usually sit above short ones, even when the market sees steady policy.
Preferred habitat theory is its cousin. You have a natural maturity you like, your habitat. To leave it you want extra pay, so rates outside your comfort zone carry a premium. That keeps the normal slope in place while letting a stretch of the curve move on its own.
Market segmentation theory takes the opposite view. Bonds of different maturities barely substitute at all, so each market sets its own rate from its own supply and demand. Short rates and long rates react to different buyers and sellers, not to one shared expectation.