TL;DR. Treasury Inflation-Protected Securities (TIPS) are U.S. Treasury bonds whose principal rises and falls with the Consumer Price Index. The coupon rate is fixed at auction, but because it is paid on the inflation-adjusted principal, the dollar interest payment grows with inflation. The yield you see quoted for TIPS is the real yield — what you earn above inflation. Get inflation right and TIPS act exactly like nominal Treasuries; get a positive inflation surprise and TIPS win.
What a TIPS Actually Is
A TIPS is a marketable U.S. Treasury security. It is sold at auction in 5-year, 10-year, and 30-year maturities, with a $100 minimum purchase and $100 increments, and you can buy them directly through TreasuryDirect or on the secondary market through a broker.[1]
Three features set TIPS apart from regular (“nominal”) Treasuries:
- Inflation-indexed principal. The par value is adjusted using a published Consumer Price Index. When inflation runs positive, par goes up; when inflation runs negative, par goes down.[1]
- Fixed coupon rate, variable coupon dollars. The coupon rate is set at auction and never changes. But because the coupon is calculated as rate × current adjusted principal, the dollar payment moves with inflation.[1]
- Deflation floor at maturity. At maturity, you receive the adjusted principal or the original principal, whichever is greater. You can never get back less than face.[1]
Coupons are paid every six months, and the auction-set rate is never less than 0.125%.[1]
The Mental Model: Real Yield, Breakeven Inflation, and Nominal Yield
The cleanest way to think about TIPS is as the real half of a nominal Treasury. A nominal 10-year Treasury yield embeds two pieces: how much return investors want above inflation, and how much inflation they expect over the life of the bond. TIPS strip out the second piece by indexing principal to CPI, so the yield that’s left over — the real yield — is what an investor earns in inflation-adjusted dollars.
The difference between the nominal yield and the real yield is called breakeven inflation. It is the market-implied average inflation rate over the life of the bond at which a nominal Treasury and a TIPS deliver the same dollar return.
Nominal Treasury yield ≈ Real (TIPS) yield + Breakeven inflation
If 10-year nominal Treasuries yield 4.50% and 10-year TIPS yield 2.00%, the market is pricing roughly 2.50% average CPI inflation over the next ten years. If realized inflation comes in at 3.50%, the TIPS holder ends up ahead of the nominal holder; if inflation undershoots to 1.50%, the nominal holder wins. The Federal Reserve publishes both the daily real yield curve and the breakeven inflation series in its H.15 release.[2]
A Worked Example
Suppose you buy $10,000 face value of a new 10-year TIPS at a 1.50% coupon rate. Track what happens over the first year if CPI rises 3.0%:
- Start of year: adjusted principal = $10,000. Annualized coupon = 1.50% × $10,000 = $150 (paid as two $75 semi-annual coupons).
- After one year of 3% CPI: adjusted principal = $10,000 × 1.03 = $10,300. Annualized coupon = 1.50% × $10,300 = $154.50.
- After ten years at compound 3.0% CPI: adjusted principal ≈ $10,000 × 1.0310 ≈ $13,439. Final coupon ≈ 1.50% × $13,439 ≈ $202. At maturity you receive the $13,439 inflation-adjusted principal.[1]
Now suppose CPI fell 1.0% per year over the same period. The adjusted principal would drift to about $9,044. But because TIPS have a deflation floor at maturity, you would still get back the original $10,000 face value.[1] Note that the floor only applies at maturity — coupons paid along the way are calculated on the deflated principal.
TIPS vs. Nominal Treasury at a Glance
| Feature | Nominal Treasury | TIPS |
|---|---|---|
| Maturities offered | 4 wk to 30 yr | 5, 10, 30 yr |
| Minimum purchase | $100 | $100 |
| Coupon | Fixed dollar amount | Fixed rate on adjusted principal |
| Principal at maturity | Original face | Max(adjusted, original) |
| Quoted yield | Nominal yield | Real yield |
| Wins when… | Realized inflation < breakeven | Realized inflation > breakeven |
| State/local tax | Exempt | Exempt |
| Federal tax on inflation accrual | N/A | Taxed annually (“phantom income”) |
Visualizing the Inflation Adjustment
Decomposing a Nominal Treasury Yield
The Four Mistakes People Make With TIPS
1. Treating real yield like nominal yield
A 2.00% TIPS yield is not a 2.00% nominal yield. It is a 2.00% yield above realized CPI. Compare TIPS to nominals using the breakeven, not the headline number.
2. Forgetting phantom income
The annual upward adjustment to TIPS principal is taxable as ordinary income at the federal level in the year it accrues — even though you do not receive the cash until you sell or until maturity. TIPS held in taxable accounts can therefore generate a tax bill larger than the coupon cash you actually pocket. This is why TIPS are typically held in IRAs, 401(k)s, or other tax-deferred accounts. TIPS, like all Treasuries, are exempt from state and local income tax.[1]
3. Assuming TIPS can’t lose money short-term
TIPS prices still move with real yields. When the real yield curve sells off — as it did in 2022 — long-dated TIPS lose principal value just like any other long-duration bond. The inflation hedge protects your real purchasing power if held to maturity. It does not protect mark-to-market value in the meantime.
4. Confusing TIPS with I Bonds
I Bonds and TIPS are different products. I Bonds are non-marketable savings bonds with a composite rate that resets every six months and a $10,000 annual purchase limit per person. TIPS are marketable securities with no purchase limit and a fixed real coupon. The principal-adjustment mechanic is loosely similar; almost everything else is not.
Where TIPS Fit in a Portfolio
TIPS are most useful when an investor’s liabilities are inflation-linked — for example, a retiree whose living expenses scale with CPI, or a pension fund with cost-of-living-adjusted liabilities. In those cases, TIPS act as a near-perfect asset-liability match. For investors with nominal liabilities (a fixed mortgage, a fixed-dollar bequest), nominal Treasuries can be a closer match.
The other angle is diversification. Nominal bonds tend to do poorly in unexpected inflation regimes — exactly when TIPS do well. Holding a slice of TIPS alongside nominal bonds gives a fixed-income book some protection against inflation surprises without giving up the safety profile of a Treasury obligation.
What to Learn Next
- Breakeven inflation: the market’s real-time forecast of average CPI over a given horizon.
- Bond duration and convexity: long-dated TIPS have meaningful real-rate duration; price moves with real yields the same way nominal bonds move with nominal yields.
- The Treasury yield curve: the H.15 release publishes both nominal and real curves and is the reference dataset most market participants use.
- I Bonds: the savings-bond cousin of TIPS, with different rate-setting and liquidity rules.
Sources
- U.S. Department of the Treasury / TreasuryDirect — Treasury Inflation Protected Securities (TIPS)
- Board of Governors of the Federal Reserve System — H.15 Selected Interest Rates (daily release)
Disclosure: This article was produced with AI assistance and reviewed before publication. It is for informational purposes only and is not investment advice.