Learn / Risk & ALM
Yield curves
A yield curve is a picture of interest rates by maturity. The horizontal axis is time: two years, ten years, thirty years. The vertical axis is the yield for that maturity. One rate is a single point. A curve is the set of points.
Rates do not have to move together. The two-year yield can rise while the thirty-year yield falls. Every later page about shocks and duration starts from that fact.
01
Three points make a classroom curve
This track draws three points: the 2-year, the 10-year, and the 30-year. A full Treasury curve has many more maturities. Three points are enough to see a slope, a hump, or a twist.
A normal classroom curve has the 2-year at 3.50%, the 10-year at 4.00%, and the 30-year at 4.50%. Longer maturity, higher yield. That is one shape, not a law.
02
Spot, forward, par, and the discount
A spot rate is the yield from today out to one maturity, with no coupons along the way. A discount factor turns a future dollar into today’s value using that spot rate. One dollar received in one year, discounted at 4%, is worth 1 / 1.04, about $0.9615 today.
A forward rate is the rate agreed today for a loan that starts later. It is baked out of two spot rates. If the market will lend to year 1 at one rate and to year 2 at another, the rate from year 1 to year 2 is the forward. You do not need a new trade to see it. It is already in the curve.
A par rate is the coupon that makes a coupon bond price at par, 100. Bootstrapping walks from short par rates to longer ones and peels out the discount factors, one maturity at a time. The swap rate in the interest-rate swap lesson is a par rate on the swap curve: the fixed rate that makes a new swap worth about zero.
03
Normal, inverted, flat, and humped
Normal means longer yields are higher. Inverted means shorter yields are higher. Flat means the yields are about the same. Humped means a middle maturity is the high point and both ends sit lower.
The shape is a description of today’s points. It is not a forecast that the curve will stay that way. Pick a shape and read the three numbers out loud.
Teaching lab
Four curve shapes
Pick a shape. The picture uses classroom yields, not today’s Treasury curve.