Inflation is the quietest tax in the system. It does not arrive with a bill. It does not show up on a pay stub. It simply makes the dollar in your savings buy less than it did last year, and a little less than that the year after. Anyone holding cash or conventional bonds eats this loss in slow installments. Treasury Inflation-Protected Securities — TIPS — are the U.S. government's answer to that quiet erosion. They are also one of the least understood instruments most retail investors will ever own.
TIPS are direct obligations of the United States Treasury, like ordinary Treasury notes and bonds. The difference is in how they handle inflation. With a conventional Treasury, you lock in a fixed coupon rate at issuance and accept whatever inflation happens to be over the holding period as your problem. With a TIPS, the principal itself moves with inflation. The fixed coupon rate is applied to that adjusting principal, so both the interest payments and the eventual repayment grow as the consumer price index rises.
How a TIPS actually works
The mechanics are worth getting right, because most casual descriptions blur them.
A TIPS starts with a face value (say $1,000) and a fixed real coupon rate (say 1.8%). Each business day, the Treasury adjusts the principal by the change in the non-seasonally-adjusted Consumer Price Index for All Urban Consumers (CPI-U), with a roughly two-month lag. If inflation runs at 3% over a year, the principal at year-end is around $1,030, not $1,000.
Twice a year, the Treasury pays a coupon equal to the real rate times the current (adjusted) principal. So in our example, the first six-month coupon would be 1.8% × $1,015 ≈ $9.14, not 1.8% × $1,000. The next six months it would be larger still. At maturity, you receive the adjusted principal — or the original face value, whichever is greater.
That last clause matters. TIPS have a deflation floor. If the consumer price index falls over the life of the bond, you still get back at least your original principal. You do not, however, get your peak adjusted principal back; if a bond was inflated up to $1,200 and then deflation rolled it back to $1,100, you receive $1,100 at maturity. (Coupons during the deflationary period also fall, since they are paid on the lower running principal.)
Maturities on offer in the regular Treasury auction calendar are 5-year, 10-year, and 30-year. The 30-year TIPS, in particular, is one of the few liquid instruments anywhere that lets a retail investor lock in inflation protection for decades.
The number to actually watch
The fixed coupon on a TIPS is a real yield, not a nominal one.
This is the single most important conceptual hurdle. A conventional 10-year Treasury yielding 4.3% is offering you 4.3% in nominal dollars. If inflation runs at 2.5%, you net about 1.8% in real terms. A 10-year TIPS yielding 1.8% is offering you 1.8% in real terms, period. Whatever inflation does, your real yield to maturity is approximately 1.8%.
Because of this, comparing TIPS yields to nominal Treasury yields is the wrong question. The right question is: what does the difference between the two imply? That difference, sometimes called the breakeven inflation rate, is roughly the average inflation rate the market expects over the matching maturity. If 10-year nominals yield 4.3% and 10-year TIPS yield 1.8%, the breakeven is about 2.5%. Hold the TIPS if you think actual inflation will run hotter than 2.5% over a decade; hold the nominal if you think it will run cooler.
This makes TIPS a particularly clean tool for thinking about inflation expectations, even for investors who never buy them.
What TIPS protect — and what they don't
TIPS protect against unexpected CPI inflation. They do not protect against:
Personal inflation. CPI is a national basket. Your basket — health insurance heavy, college tuition heavy, urban rent heavy — may run faster or slower than the official measure.
Tax drag. Here is where TIPS get genuinely awkward in taxable accounts. The annual upward principal adjustment counts as imputed interest income for federal tax purposes in the year it accrues, even though you do not actually receive that principal until maturity. You owe tax on income you cannot yet spend. For this reason, TIPS are usually held in tax-advantaged accounts — IRAs, Roth IRAs, 401(k)s — where this phantom-income problem disappears.
Interest rate risk on the secondary market. Real yields move. If real yields rise after you buy, the market price of your TIPS falls, just as with any bond. If you hold to maturity, this does not affect what you ultimately receive. If you might need to sell early, it does.
Deflation surprise. Newly issued TIPS at low real yields can lose to a sustained deflation, especially if you bought at a premium price after long-running inflation expectations had bid the bonds up.
Where they fit
TIPS do something specific that no other commonly available instrument does: they remove inflation risk from the bond portion of a portfolio. They are not yield-maximizing. Their real yield is, on average, lower than what stocks have produced. But they are certainty-of-purchasing-power-maximizing, and that is a different and increasingly valuable thing.
Several use cases stand out.
Funding long-dated nominal-spending obligations. Retirees with a thirty-year planning horizon can build a TIPS ladder that essentially guarantees a real income stream — exactly the thing inflation can otherwise quietly hollow out.
Hedging the bond side of a balanced portfolio. A portfolio with stocks and conventional bonds is doubly exposed to a sustained inflation shock. Adding TIPS to the bond sleeve reduces that correlation.
Buying I-Bonds is not always enough. I-Bonds are the retail cousin of TIPS — also inflation-indexed, but capped at $10,000 per person per year and locked up for at least one year. For investors who need more capacity or longer maturities, TIPS are the institutional version with no purchase limit.
The shortest summary is this: if you own bonds at all, and especially if you own them in retirement accounts, TIPS deserve to be in the conversation. They are not glamorous. They will not double your money. They simply pay you, slowly and reliably, in dollars that still buy what they used to. In a world that has spent the last decade reminding us inflation is not safely buried, that is not a small thing.
