According to Investopedia, the yield curve graphs the relationship between bond yields and bond maturity. As bonds with longer maturities usually carry higher risk, such bonds have higher yields than the bonds with shorter maturities. Due to this, a normal yield curve reflects increasing bond yields as maturity increases. However, the yield curve can sometimes become flat or inverted. The left graph selects three different time periods to show the three different yield curve shapes: April 2021 shows the normal upward sloping yield curve, May 2007 shows a flat yield curve, and August 2000 shows an inverted yield curve.
