Treasury Inflation-Protected Securities
Every projection of a long retirement is really a bet about inflation, and conventional bonds take the wrong side of it. They promise a fixed number of dollars, which is exactly the thing inflation erodes. TIPS promise something different: a principal that rises with the index, so the purchasing power rather than the number is what is protected.
- Principal adjusts:: The face amount rises with the index, so the same coupon rate pays more dollars as prices rise.
- A real yield:: The stated rate is a return above inflation, not a total return.
- Taxed before received:: The annual principal adjustment is taxable income in the year it accrues, though no cash arrives.
- Deflation floor at maturity:: At maturity the holder receives the greater of the adjusted principal or the original.
Where the AI summary above gets this wrong
"Bonds protect a retirement portfolio from risk."
That's surface-true. Here's what it misses:
- Conventional bonds do not protect against the main long-term risk — They protect against equity falls, which is valuable. They offer nothing against inflation, which over a thirty-year retirement is the risk most likely to reduce a standard of living. A portfolio of nominal bonds and shares carries no explicit inflation hedge at all.
- The stated yield is a real yield — A TIPS quoted at one and a half per cent is offering one and a half per cent above inflation, not in total. Comparing it directly to a nominal bond's yield is comparing different things, and the gap between the two is roughly what the market expects inflation to be.
- The tax treatment is genuinely awkward — The annual increase in principal is taxable in the year it accrues, even though the money is not received until maturity. In a taxable account that means paying tax on income you have not been paid, which is why TIPS are usually held inside tax-sheltered accounts.
01 How the adjustment works
A TIPS has a fixed coupon rate, but the principal it is paid on moves with the consumer price index. When prices rise, the principal rises, and the same coupon rate produces a larger payment. At maturity the holder receives the adjusted principal, with a floor at the original amount if prices have fallen overall.
The result is that the return is expressed in real terms. Whatever inflation turns out to be, the holder receives the stated rate on top of it — which is the opposite of the position a conventional bondholder takes.
They are issued in several maturities and can be bought at auction directly or through funds. A fund is simpler and gives the same exposure; individual securities give a known real amount on a known date, which is what makes them useful for matching a specific future expense.
Shows: how much more nominal income is required after the years shown to buy what today's spending buys, at the inflation rate you enter. Ignores: that spending patterns change with age, that some costs rise faster than the general index, tax on the extra income, and any income that already adjusts with inflation.
02 Reading the yield, and the tax
The quoted yield on a TIPS is a real yield. A nominal Treasury of the same maturity quotes a yield that includes expected inflation, and the difference between the two is the break-even rate — the inflation rate at which the two would produce the same outcome.
Above that rate, the TIPS wins; below it, the conventional bond does. Buying TIPS is therefore not a prediction that inflation will be high; it is a decision to stop taking a position on it at all.
The tax is the awkward part. The annual principal adjustment is federally taxable in the year it accrues, though no cash is received until maturity. In a taxable account that produces tax on phantom income; held in an IRA or 401(k) the problem disappears, which is where the asset location answer points.
Source: TIPS
03 Where they fit
The strongest use is matching known future spending. Someone who wants a guaranteed real amount available in ten years can buy a TIPS maturing then, and the purchasing power is fixed regardless of what happens to prices in between.
The second use is as part of the general bond allocation, replacing some nominal exposure so the portfolio is not entirely on one side of the inflation question. How much depends on how much of the household's income already adjusts — someone whose spending is largely covered by inflation-linked Social Security needs less than someone living on a fixed pension.
That last point is the one worth thinking through. The inflation exposure of a plan is the gap between spending and the income that rises with prices. TIPS are the instrument that closes it, and the size of the gap is what determines how many are needed.
Source: Bonds
The question I ask before discussing TIPS at all is how much of the household's spending is already covered by income that rises with prices. For someone whose Social Security covers most of their essential costs, the inflation gap is small and TIPS are a refinement. For someone living mainly on a fixed pension and a portfolio, the gap is the largest unhedged risk in the plan, and this is the only instrument that directly addresses it.
FAQ
Are TIPS better than regular Treasury bonds?
Neither is better in general. TIPS win if inflation exceeds the break-even rate implied by the two yields, and conventional bonds win if it does not. Buying TIPS removes the bet rather than winning it.
Why should TIPS be held in a retirement account?
The annual principal adjustment is taxable in the year it accrues even though no cash is received until maturity. Inside an IRA or 401(k) that timing problem does not arise.
Do TIPS lose value if prices fall?
The principal adjusts downward with the index, but at maturity the holder receives the greater of the adjusted principal or the original face amount, so the original investment is floored.
Sources
Regulator references
- Treasury inflation-protected securities · U.S. Securities and Exchange Commission · 2026How the principal adjusts with inflation and what that does to the payments.Last verified: 2026-09-07
- TIPS · TreasuryDirect, U.S. Department of the Treasury · 2026Terms available, how they are auctioned, and how the adjustment is applied.Last verified: 2026-09-07
- Bonds · U.S. Securities and Exchange Commission · 2026The conventional bond a TIPS is compared against.Last verified: 2026-09-07
Calculator unit tests · the assertions this page's worked example is checked against, and their last result
Changelog
- 2026-09-07 — initial publish (new format)
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Jordan Reeves
Founder of Talk Through Wealth. A software engineer for over a decade before turning to retirement planning, Jordan built the projection engine after watching family members get fragmented, country-by-country advice that never reconciled. He writes about retirement the way the engine computes it: month-by-month, lifetime-long, and skeptical of any rule of thumb that hasn't been run through the math.