Treasury Inflation-Protected Securities

August 25, 2024 Fixed Income

Treasury Inflation-Protected Securities are marketable U.S. Treasury bonds whose principal adjusts with CPI, changing coupon payments and maturity value.

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Treasury Inflation-Protected Securities (TIPS) are marketable U.S. Treasury securities whose principal adjusts with changes in the Consumer Price Index for All Urban Consumers (CPI-U). TIPS pay a fixed coupon rate on the inflation-adjusted principal, so the dollar interest payment can rise with inflation and fall with deflation.

Key Takeaways

TIPS are issued by the U.S. Treasury and currently come in 5-year, 10-year, and 30-year maturities.
The coupon rate is fixed at auction, but the principal amount used to calculate interest adjusts with CPI-U.
At maturity, Treasury pays the greater of original principal or inflation-adjusted principal, but market value before maturity can rise or fall.
TIPS reduce inflation risk, not all risk; real yields, taxes, liquidity, fund fees, and sale timing still matter.

How TIPS Principal And Interest Work

\text{Adjusted Principal} = \text{Original Principal} \times \text{Index Ratio}

\text{Semiannual Interest} = \text{Adjusted Principal} \times \frac{\text{Coupon Rate}}{2}

For example, if 1,000 of TIPS principal is adjusted to 1,030 and the annual coupon rate is 1.50%, the semiannual interest payment is 1,030 x 0.015 / 2 = 7.725. The formula shows why TIPS coupon dollars can change even though the coupon rate itself is fixed.

TIPS vs. Nominal Treasury Bonds

Feature	TIPS	Nominal Treasury Bond
Principal	Adjusts with CPI-U.	Fixed at face value.
Coupon rate	Fixed rate applied to adjusted principal.	Fixed rate applied to fixed principal.
Inflation exposure	Lower, based on the TIPS formula.	Higher, because payments are nominal.
Yield focus	Real yield.	Nominal yield.
Main risk to compare	Real-rate risk, index lag, taxes, liquidity, and sale price.	Nominal-rate risk, inflation risk, liquidity, and sale price.

Why TIPS Matter

TIPS are useful when the investor needs U.S. Treasury credit exposure plus a direct inflation adjustment. They are commonly analyzed for retirement spending, pension liabilities, real-return benchmarks, and inflation-hedging allocations. The key comparison is not simply TIPS versus “safe bonds”; it is real yield, expected inflation, maturity, tax location, liquidity needs, and whether the investor plans to hold to maturity.

Common Mistakes

Assuming TIPS cannot lose market value before maturity.
Treating a TIPS mutual fund or ETF as the same as holding an individual TIPS to maturity.
Ignoring federal tax on interest and principal adjustments in taxable accounts.
Comparing TIPS coupon rates directly with nominal Treasury coupon rates.
Assuming CPI-U matches every household’s personal inflation experience.

Public Source Checks

TreasuryDirect TIPS explains TIPS principal adjustment, maturities, interest payments, minimum purchase, and maturity treatment.
TreasuryDirect marketable securities redemption explains maturity and redemption context for Treasury marketable securities.
BLS CPI FAQ explains what CPI measures and its limitations.

Inflation-Indexed Securities: Broader category for inflation-adjusted securities.
Consumer Price Index: The inflation measure used in many inflation-linked securities.
Series I Bond: A retail savings bond with different inflation-linked mechanics.
Real Return: Return after inflation effects.
Interest Income: TIPS pay interest on adjusted principal.

FAQs

Can TIPS lose money?

Yes. TIPS can decline in market value before maturity if real yields rise, liquidity weakens, or the investor sells at an unfavorable price. The original-principal floor applies at maturity for Treasury-issued TIPS, not to every sale price before maturity.

Are TIPS the same as I bonds?

No. TIPS are marketable Treasury securities with CPI-adjusted principal and periodic interest. I bonds are nonmarketable savings bonds with a composite rate and different redemption rules.

Revised on Sunday, June 21, 2026

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