In plain terms — A nominal rate combines real and inflation compensation. A breakeven compares nominal and indexed bonds but also embeds premia and liquidity.
The relationship between nominal yield, real yield and inflation compensation, including risk premia and liquidity.
What it actually observes
A nominal yield pays in money terms, while a real yield aims to isolate purchasing power. Breakeven inflation is the difference between comparable nominal and indexed yields, not an observed measure of future inflation.
That gap combines expectations, inflation risk premium, liquidity and indexation details. Issuer, maturity and conventions must match before comparison.
Operational reading
Align curve, duration, price index and the lag with which indexed principal adjusts. Off-the-run pricing, tax differences and liquidity can shift the spread without changing inflation expectations.
Decompose a breakeven move using real yields, inflation swaps and surveys. When those measures diverge, the defensible conclusion is uncertainty about composition rather than a point forecast.
Worked interpretation
A higher breakeven may reflect expected inflation, an inflation premium or indexed-bond liquidity; more evidence is needed.
Advanced level
Term-structure models separate expectations and premia by imposing assumptions that must be disclosed. Premia can change with risk aversion, indexed-bond supply and hedging demand.
Forward breakevens and constant-maturity measures solve some problems but introduce interpolation and tail sensitivity. Ranges and cross-instrument comparisons are more informative than a single curve.
Limits and common errors
Breakeven inflation is not a pure forecast and may move because of liquidity or premia. Differences among CPI, the contractual index and horizon prevent a direct comparison with every published inflation measure.
Sources
- U.S. Treasury, TIPS, official documentation — security terms, inflation adjustment, interest calculation, auctions and taxation of TIPS.
- Federal Reserve Bank of St. Louis, FRED, official documentation — downloadable nominal-yield, real-yield and market breakeven time series.
- ECB, Inflation expectations, official documentation — quarterly professional forecasts for inflation, real GDP growth and unemployment.