Inflation-Linked Government Securities

Compare government inflation-linked securities by index, principal adjustment, marketability, tax timing, and maturity protection.

Inflation-linked government securities adjust principal, interest, or redemption value using an inflation measure. Their purpose is to reduce the mismatch between fixed nominal payments and changing purchasing power, but each program uses its own index, timing, tax, and redemption rules.

In the United States, Treasury Inflation-Protected Securities are marketable securities whose principal adjusts with CPI-U. Series I Bonds are nonmarketable savings bonds with a composite interest rate and separate purchase and redemption rules.

Comparison Questions

QuestionWhy it matters
What inflation index is used?A national CPI may not match the holder’s actual costs or liability
What part of the cash flow adjusts?Principal, coupon, or redemption value can respond differently
How long is the index lag?Recent inflation may not enter the calculation immediately
Is the security marketable?Marketability allows an early sale but introduces price risk
Is there a maturity or redemption floor?Protection may apply only on a specific date and to a defined amount
When is tax recognized?Inflation accrual can be taxable before cash is received
Is it an individual security or fund?A fund does not give each shareholder one contractual maturity payment

Nominal Yield vs. Real Yield

Nominal government securities promise fixed-dollar cash flows. Inflation-linked securities are generally analyzed using real yield because their payment base changes with inflation. The difference between a nominal Treasury yield and a comparable TIPS real yield is often called breakeven inflation or inflation compensation.

That spread is not a pure forecast. It can include expected inflation, inflation risk premiums, liquidity differences, supply and demand, and imperfect maturity matching.

Common Mistakes

  • Treating inflation protection as protection from market-price losses.
  • Assuming the inflation index matches every household or institution.
  • Comparing a TIPS coupon rate directly with a nominal bond yield.
  • Ignoring index lag and deflation mechanics.
  • Assuming a maturity floor protects the purchase price.
  • Overlooking annual tax reporting on inflation accrual.
  • Treating a TIPS fund as an individual TIPS held to maturity.

For broader structures outside U.S. government programs, see Inflation-Linked Bonds and Indexed Securities. For nominal Treasury context, see Treasury Securities.

This section is educational and does not recommend an inflation-linked security, account, or tax strategy.

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TIPS

Treasury Inflation-Protected Securities adjust principal with CPI-U and pay fixed-rate interest on the adjusted amount.

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