Definition: An inverted yield curve is when the yields on bonds with a shorter duration are higher than the yields on bonds that have a longer duration. This usually only happens with Treasury note yields. That's when yields on one-month, six-month or one-year Treasury bills are higher than yields on 10-year or 30-year Treasury bonds.
Why are inverted yield curves so unusual? In a normal yield curve, the short-term bills yield less than the long-term bonds. That's because investors expect a lower return when their money is tied up for a shorter time period. They require a higher yield to give them more return on a long-term investment.
What Does an Inverted Yield Curve Mean?
An inverted yield curve means that investors have so little confidence in the economy that they would rather buy a 10-year Treasury note, and tie up their money for ten years -- even though they receive a lower yield! That makes absolutely no logical sense. Normally, investors expect more of a return for a long-term investment.
However, an inverted yield curve means investors believe they will make more by holding onto the longer-term bond than if they bought a short-term Treasury bill. That's because they'd just have to turn around and reinvest that money in another bill. If they believe a recession is coming, they expect the value of the short-term bills to plummet sometime in the next year. That's because the Federal Reserve usually lowers the Fed funds rate when economic growth slows. Short-term Treasury bill yields usually closely track the Fed funds rate.
So why does the yield curve invert? As investors flock to long-term Treasury bonds, the yield on those bonds lower. That's because they are in demand, so the don't need as high a yield to attract investors. The demand for short-term Treasury bills falls, so they need to pay a higher yield to attract investors. Eventually, the yield on short-term bills rises higher than the yield on long-term bonds, and the yield curve inverts.
During normal growth, the yield on a 30-year bond will be 3 points higher than a 3-month bill. However, if investors believe that the economy will be slowing over the next couple of years, and then speeding up again in 10-20 years, they will be content to tie up their money until then.
When Did the Inverted Yield Curve Forecast a Recession?
The Treasury yield curve inverted before the recessions of 2000, 1991, and 1981. The yield curve also forecast the 2008 financial crisis two years earlier. On July 17 2006, the yield curve inverted when the 10-year note yielded 5.06%, less than the 3-month bill at 5.11%. This was a few weeks after the Federal Reserve raised the Fed funds rate to 5.75%. The Fed was trying to cool off the housing market, which was in an asset bubble. Obviously, investors thought this was a step in the wrong direction, and the yield curve inverted.
Unfortunately, economists ignored the warning. They thought that as long as long-term yields were low it would provide enough liquidity in the economy to prevent a recession. They were wrong.
The yield curve stayed inverted until June 2007. Throughout the summer, it flip-flopped back and forth, between an inverted and flat yield curve. By September 2007, the Fed finally became concerned, and lowered the Fed funds rate to 4.75%. This was a 1/2 point, which was a big drop and was meant to send a signal to the markets that the Fed would act aggressively to add liquidity. The Fed continued to lower the rate ten times until it reached zero by the end of 2008. The yield curve was no longer inverted, but it was too late. The economy had entered the worst recession since the Great Depression. For more on the exact timing of the cuts, see Current Fed Funds Rate. Word to the wise - never ignore an inverted yield curve.
Check out a cool interactive tool that shows the yield curve in a graphic form through the years on Smart Money. Article updated June 24, 2013
Examples: Foreign demand for U.S. Treasury Bonds helped create an inverted yield curve.