Trading Inflation Breakevens

Two government bonds, same maturity, same issuer — one pays a fixed coupon regardless of what happens to prices, the other's principal and coupons adjust automatically with inflation. The gap between their yields is not an accounting curiosity; it is the bond market's collective, continuously updated bet on average inflation over that exact stretch of time.

Why the gap equals a market forecast

A nominal bond promises fixed dollar cash flows; an inflation-protected bond (a TIPS in the US, a linker in the UK) promises cash flows that scale with a price index, so its real purchasing power is protected regardless of what inflation does. If an investor is indifferent between holding either bond, it must be because the extra yield the nominal bond offers exactly compensates, on average, for the inflation the TIPS investor is protected against (plus a small extra premium for the fact that TIPS are less liquid and inflation itself is uncertain, not just its average level). Rearranged, that indifference condition is exactly the decomposition seen elsewhere:

$$BEI = y_{nominal} - y_{TIPS}$$

In words: breakeven inflation equals the nominal yield minus the real yield paid on the inflation-protected bond of the same maturity — the market's implied average inflation rate priced into that maturity.

Treat the line above as expected inflation plotted against maturity — the 5-year breakeven and the 10-year breakeven are two points on a curve of the market's inflation expectations at different horizons, and the shape of that curve (rising, flat, falling) is itself a tradeable view.

Worked example

The 10-year nominal Treasury yields 4.30% and the 10-year TIPS yields 1.90%. Breakeven inflation is:

$$4.30\% - 1.90\% = 2.40\%$$

The market is pricing average CPI inflation of about 2.40% per year over the next decade. A trader who believes structural pressures (deglobalization, persistent fiscal deficits, sticky wage growth) will push realized average inflation closer to 3.5% over that window would buy breakevens: go long TIPS and short an equal-duration amount of nominal Treasuries, a position that profits as the breakeven widens toward that higher expected inflation, without taking on outright exposure to the level of real interest rates.

What this means in practice

Breakeven trades are popular precisely because they isolate a pure inflation view from the real-rate view: an investor who has a strong opinion about inflation but no particular opinion about growth or real interest rates can express it directly, rather than bundling it into an outright nominal bond position that would also be exposed to real-yield moves.