I Bonds and TIPS: Inflation-Protected Savings Guide

Inflation quietly erodes the value of money sitting in a savings account earning a low fixed rate. If prices rise faster than your interest, you lose purchasing power even while your account balance grows. I Bonds and Treasury Inflation-Protected Securities (TIPS) are two U.S. government-backed tools specifically engineered to solve that problem — and understanding how each one works is the first step toward using them wisely.

Table of Contents

1. What Are I Bonds and TIPS?

Both I Bonds and TIPS are debt securities issued by the United States federal government — meaning when you buy one, you are effectively lending money to the U.S. Treasury. The government promises to repay you with interest, and that interest is explicitly tied to inflation. Beyond that shared foundation, the two instruments are quite different in structure, access, and behavior.

I Bonds (Series I Savings Bonds)

I Bonds are non-marketable savings bonds — you cannot buy or sell them on the open market. You purchase them directly from the U.S. government through TreasuryDirect, the official platform for retail Treasury purchases. They are designed to be held, not traded. The Treasury sets a composite interest rate made up of two parts: a fixed rate that stays with your bond for its life, and a variable inflation rate that adjusts every six months based on changes in the Consumer Price Index for All Urban Consumers (CPI-U).

TIPS (Treasury Inflation-Protected Securities)

TIPS are marketable Treasury securities, meaning they can be bought and sold on the secondary bond market. They are available through TreasuryDirect, brokerage accounts, and mutual funds or ETFs that hold TIPS. Unlike I Bonds, the inflation adjustment on TIPS works differently: instead of changing your interest rate, it adjusts the principal (face value) of the bond upward with inflation. Your interest payments, which are calculated as a fixed percentage of that principal, therefore also rise when inflation rises.

TIPS are issued in maturities of 5, 10, and 30 years and are backed by the full faith and credit of the U.S. government.

2. How Each One Works — and How They Compare

How I Bond Interest Is Calculated

The I Bond composite rate is the combination of its fixed rate and its semiannual inflation rate. The fixed rate is set at issuance and never changes for that bond. The inflation component is reset every May and November based on CPI-U data from the preceding six-month period. Your bond earns interest monthly and compounds semiannually. Because the rate resets regularly, your total return over time reflects actual inflation experience — rising when prices spike and falling when inflation cools.

How TIPS Principal Adjustment Works

With TIPS, the Treasury adjusts the bond’s principal daily based on changes in the CPI-U. If you buy a TIPS with a $1,000 face value and inflation rises, the adjusted principal might become $1,040. Your fixed coupon rate is then applied to $1,040 rather than $1,000, so your interest payment grows. At maturity, you receive the greater of the inflation-adjusted principal or the original face value — meaning deflation cannot reduce your payout below what you originally paid (at issuance).

Tax Treatment

• I Bonds: Federal income tax applies to interest earned, but it can be deferred until you cash the bond or it reaches maturity (30 years). State and local taxes do not apply. Under certain conditions related to education expenses, I Bond interest may be excludable from federal tax — check current IRS rules and income thresholds, as these change.
• TIPS: The inflation adjustment to principal is taxable as federal income in the year it occurs, even though you do not receive that cash until maturity. This “phantom income” tax effect is important to plan for. State and local taxes do not apply. Holding TIPS inside a tax-advantaged account (like an IRA) is one way investors manage this.

Side-by-Side Comparison Table

3. Step-by-Step: How to Get Started

Getting your first inflation-protected security takes more preparation than opening a savings account, but the process is straightforward once you know the sequence.

4. Common Mistakes and Cautions

Treating I Bonds as a Liquid Emergency Fund

Because I Bonds cannot be redeemed for at least 12 months, they should not serve as your only emergency fund. Money you might need within a year does not belong in I Bonds.

Ignoring the Early Redemption Penalty

If you redeem an I Bond before it has been held for five years, you lose the last three months of interest. This is not catastrophic, but it can meaningfully reduce your effective return on shorter holding periods. Factor this into your timeline.

Overlooking Phantom Income on TIPS

The annual tax on TIPS principal adjustments — even though you receive no cash — surprises many first-time buyers. If you hold TIPS in a taxable account during a high-inflation period, you may owe tax on gains you cannot spend yet. Consider tax-advantaged account placement.

Assuming I Bonds Always Beat Inflation Perfectly

The variable component of I Bond rates is based on CPI-U data with a six-month lag. Your bond’s rate reflects inflation from the prior measurement period, not real-time conditions. In rapidly changing inflation environments, there can be temporary mismatches.

Confusing TIPS Funds with Direct TIPS Ownership

A TIPS mutual fund or ETF holds many individual TIPS bonds. Unlike holding a single TIPS to maturity — where you are guaranteed the inflation-adjusted principal — a fund’s value fluctuates daily with interest rates. Rising interest rates can cause TIPS fund prices to fall, creating short-term losses even in an inflation-hedging instrument. This does not make funds bad, but it is a meaningful structural difference to understand before investing.

Exceeding I Bond Purchase Limits

The Treasury imposes annual purchase limits per Social Security number. Buying more than permitted is not allowed. Verify the current limits at TreasuryDirect before planning large purchases.

Checklist

• [ ] Confirm you have a stable emergency fund in a liquid account before locking money in I Bonds or long-term TIPS.
• [ ] Open a TreasuryDirect account if you plan to purchase I Bonds or buy TIPS directly from the Treasury.
• [ ] Check the current I Bond composite rate and annual purchase limit at TreasuryDirect before buying.
• [ ] Evaluate whether to hold TIPS in a tax-advantaged account to manage the phantom income tax issue.
• [ ] Record your bond issue date, fixed rate, and maturity date in a secure location.
• [ ] Review your inflation-protected holdings annually to ensure they still fit your financial goals.
• [ ] Consult a qualified tax or financial professional before making decisions that affect your overall portfolio or tax situation.

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FAQ

Q: Can I lose money on I Bonds?

A: The U.S. Treasury guarantees that your I Bond will never fall below its original purchase price — the composite rate cannot go below zero. However, if you redeem before five years, the three-month interest penalty can reduce your net gain. You will not lose your principal, but your effective return after the penalty may be lower than expected, particularly if inflation was low during your holding period.

Q: Are TIPS a good choice during low-inflation periods?

A: During periods of very low or negative inflation (deflation), TIPS principal adjustments may be minimal or could technically adjust downward. However, at maturity, the Treasury guarantees you will receive at least the original face value — so deflation cannot cause you to receive less than you paid at a new-issue auction. That said, in low-inflation environments, TIPS may underperform conventional Treasury bonds of similar maturity. Whether that trade-off makes sense depends on your expectations and risk tolerance — a topic worth discussing with a financial professional.

Q: Do I Bonds make sense for a child or as a gift?

A: Yes — the U.S. Treasury allows I Bonds to be purchased as gifts and even for minor children (with some account setup requirements). Because they are non-marketable, backed by the U.S. government, and designed for long-term holding, they are sometimes used as long-horizon savings vehicles for children. Gift and minor-account rules have specific requirements; review the current rules at TreasuryDirect and consult a financial or tax professional for your specific situation.

Disclaimer

This guide is for informational purposes only and is not tax, investment, or legal advice. Specific figures such as contribution limits, interest rates, purchase limits, and tax thresholds change annually — verify current numbers at irs.gov, TreasuryDirect, or other official sources. Consult a qualified professional for personal decisions.

Guide written as of: August 13, 2026

Guide prepared by the MoneyTechLab editorial team.