The Yield Curve Explained: Shapes, Inversions and Recession Signals

Plot the yields of US Treasuries from the shortest maturity to the longest and you get the yield curve. It is one of the most closely watched lines in finance because it captures, in a single shape, what markets expect for interest rates, inflation and growth. When the curve turns upside down, it tends to make headlines, and for good reason.

How the curve is built

The Treasury publishes daily par yield curve rates for maturities from one month to 30 years on its website. Each point represents the yield on a Treasury of that maturity. Connect the points, from left (short-term) to right (long-term), and you have the curve.

Two forces mostly determine its shape:

• Expectations for short-term rates. The yield on a 10-year Treasury reflects, roughly, what investors expect short-term rates to average over the next decade. If they expect the Fed to cut rates, long yields tend to fall below short yields.
• The term premium. Investors usually want extra compensation for tying money up for longer and accepting more interest rate and inflation risk. That premium can be positive or, at times, close to zero or negative.

The short end is anchored by the Federal Reserve's policy rate. The long end is set by the market.

The four shapes

The curve can also be "humped," with mid-range yields above both ends, or change shape in different ways at different points.

What an inversion means

An inverted curve happens when short-term yields rise above long-term ones. Usually, that is because the Fed has raised its policy rate to cool inflation, pushing up short yields, while bond investors expect the tightening to slow the economy and eventually force rate cuts, holding down long yields.

Inversions matter for two practical reasons:

1. Bank lending. Banks traditionally borrow short (deposits) and lend long (loans). When short rates exceed long rates, that business becomes less profitable, which can tighten credit.
2. The historical record. An inversion of the 10-year versus 3-month or 10-year versus 2-year spread has preceded most US recessions over the past several decades. The Federal Reserve Bank of New York publishes a model that converts the 10-year minus 3-month spread into a recession probability for the following year.

The limits of the signal

The yield curve's reputation is strong, but it is not a timer:

• The lag varies. Recessions have followed inversions anywhere from months to a couple of years later.
• False signals happen. Not every inversion has been followed by a recession, and a prolonged inversion beginning in 2022 prompted extensive debate about whether the signal had weakened.
• Distortions. Large-scale bond buying by the Fed, foreign demand for Treasuries and shifts in the term premium can push long yields down for reasons unrelated to growth expectations.
• Un-inversion is not an all-clear. Historically, the curve has often re-steepened shortly before or during a downturn, as the Fed began cutting short-term rates.

Treat the curve as one input alongside employment data, corporate earnings, credit spreads and consumer spending.

Which spread to watch

• 10-year minus 2-year (2s10s): the most quoted in financial media. It compares two market-set yields.
• 10-year minus 3-month: often favored in Federal Reserve research, because the 3-month yield closely tracks current policy.

Both are available free and updated daily on the St. Louis Fed's FRED database (series T10Y2Y and T10Y3M). A positive number means the curve is upward-sloping at that segment; a negative number means it is inverted.

Who moves which end of the curve

The two ends of the curve respond to different forces, and separating them is the key to interpreting a move.

The short end, out to about two years, is dominated by expectations for the federal funds rate. When the FOMC raises or cuts its target range, or signals that it will, bill and 2-year yields adjust quickly. Comments from Fed officials and the quarterly projections can move them within minutes.

The long end reflects a mix of expected future short rates, expected inflation and the term premium. It is also shaped by the supply of Treasuries: large federal deficits mean more long-term debt must be sold, and if buyers demand more compensation to absorb it, long yields can rise even without any change in Fed policy. Global demand matters too, since foreign investors, pension funds and insurers hold large amounts of long-dated Treasuries.

Bull and bear steepening and flattening

Traders describe curve moves with a vocabulary worth knowing:

• Bull steepening: short yields fall faster than long yields, often when markets expect Fed rate cuts.
• Bear steepening: long yields rise faster than short yields, often on inflation or government borrowing concerns.
• Bull flattening: long yields fall faster than short yields, often on growth worries.
• Bear flattening: short yields rise faster than long yields, often when the Fed is raising rates.

("Bull" refers to rising bond prices, which means falling yields.)

What it means for households

• Savers: when the curve is inverted, short-term CDs, Treasury bills and money market funds can pay as much as or more than long-term bonds.
• Borrowers: fixed-rate mortgages tend to track longer-term Treasury yields plus a spread, so a falling 10-year yield can ease mortgage rates even before the Fed cuts.
• Bond investors: the shape affects the trade-off between locking in a long-term yield and staying short to keep flexibility. A steep curve rewards extending maturity; a flat or inverted curve offers little extra pay for the extra risk.
• Stock investors: the curve is part of the broader picture of credit conditions and growth expectations.

Reading it yourself

Once a month, pull up the Treasury's daily par yield table or the FRED spread charts and ask three questions: Is the curve upward-sloping, flat or inverted? Which end has moved most since last month? Is the move coming from the Fed (the short end) or from the market's view of growth and inflation (the long end)? Those three answers will tell you more about the rate environment than most commentary.

This article is for education only and is not investment advice. It describes possible scenarios, not predictions.