A yield curve plots interest rates (yields) against time to maturity for comparable debt securities, with the U.S. Treasury curve being the most well-known example. It typically slopes upward because investors demand a risk premium for longer maturities, or because markets anticipate future interest rate hikes. However, an inverted yield curve—where short-term rates exceed long-term ones, as seen in UK government bonds in November 2004—signals expectations of falling rates and has historically preceded economic recessions. Analysts track the curve's shape using term spreads, such as the 10-year minus 3-month Treasury yield (the New York Fed's convention), which central banks use in recession-probability models. Beyond simple shapes, the curve can be flat or hump-shaped and is summarized through zero-coupon (spot), forward, and par yield curves, while its form is also shaped by supply-and-demand dynamics, such as pension funds' heavy demand for long-dated bonds.