Inflation-Indexed Bonds: TIPS, I Bonds, and Other Inflation-Protected Investments
In 2022, inflation hit 9.1% and the S&P 500 fell 18%. TIPS returned +2.8% (adjusting for inflation). I Bonds paid 9.62%. Regular bonds lost 13%. Here's how inflation-indexed bonds protect against purchasing power erosion.
Inflation-indexed bonds are government-issued securities whose principal and interest payments adjust for inflation, ensuring that your purchasing power is preserved regardless of how fast prices rise. The United States issues two main types: Treasury Inflation-Protected Securities (TIPS) and Series I Savings Bonds (I Bonds). TIPS are marketable securities with maturities of 5, 10, or 30 years, and their principal adjusts with the Consumer Price Index (CPI). I Bonds are non-marketable savings bonds with a composite rate that combines a fixed base rate with a variable inflation rate that changes every six months. Both are backed by the full faith and credit of the US government. Other countries have similar instruments: the UK offers Index-Linked Gilts, Canada offers Real Return Bonds, and Germany offers Bundeswertpapiere. Compare TIPS with other Treasury securities →
Real-world example: You buy $10,000 of 10-year TIPS with a 1% real yield. Over the first year, CPI increases by 5%. The principal adjusts to $10,500. Your interest payment is 1% of $10,500 = $105. You earn $105 on your original $10,000 investment + $500 of principal adjustment. If instead you bought a $10,000 regular 10-year Treasury note at 3% nominal yield, you would receive $300 in interest, but the $10,000 principal loses 5% purchasing power — worth only $9,500 in real terms. The TIPS investor earns more in real terms even though the nominal yield was lower. In deflation, TIPS principal adjusts downward but never falls below par at maturity. Detailed comparison of TIPS vs I Bonds →
How TIPS Work: Principal Adjustments and Real Yields
TIPS pay interest every six months at a fixed rate applied to the inflation-adjusted principal. When CPI rises, the principal increases and your interest payments rise proportionally. When CPI falls (deflation), the principal decreases, but at maturity you receive at least the original par value. The real yield on TIPS is the fixed rate above inflation that you earn. As of mid-2026, 10-year TIPS real yields are approximately 1.8% to 2.2%, down from the 2023 highs of 2.5% but significantly above the negative yields that persisted from 2012 to 2022. TIPS are auctioned by the Treasury in January, April, July, and October for 5-year and 10-year maturities, and in February, June, August, and November for 30-year maturities. You can buy TIPS directly through TreasuryDirect or through TIPS ETFs like iShares TIP or Schwab SCHP. Bond investing basics for beginners →
How I Bonds Work: Composite Rates and Purchase Limits
Series I Savings Bonds earn a composite rate that is the sum of a fixed base rate (set at purchase and held for the bond's 30-year life) plus a variable inflation rate that adjusts every May 1 and November 1 based on the most recent six months of CPI-U data. The composite rate formula is: composite rate = fixed rate + (2 x inflation rate) + (fixed rate x inflation rate). As of May 2026, the fixed rate is 1.30% and the inflation rate is 1.80%, producing a composite rate of approximately 4.94%. I Bonds have an annual purchase limit of $10,000 per person per calendar year (plus up to $5,000 from a tax refund). You can buy I Bonds only through TreasuryDirect. I Bonds cannot be redeemed within the first 12 months, and redeeming within the first 5 years forfeits the last 3 months of interest. Despite the purchase limit, I Bonds are an excellent vehicle for building an inflation-protected emergency fund or supplemental retirement savings.
TIPS ETFs and Mutual Funds for Portfolio Diversification
For investors who want inflation protection without the complexity of buying individual TIPS at auction, ETFs and mutual funds provide convenient access. The largest TIPS ETF is iShares TIP ($30+ billion AUM, 0.19% expense ratio), which tracks a broad TIPS index across all maturities. The Schwab US TIPS ETF (SCHP, 0.03% expense ratio) is the lowest-cost option. Vanguard offers the Vanguard Short-Term Inflation-Protected Securities ETF (VTIP), which focuses on TIPS with maturities under 5 years, reducing duration risk. The PIMCO 1-5 Year US TIPS Index ETF (STPZ) is another short-duration option. A common portfolio allocation is 5% to 15% of a bond portfolio in TIPS, with higher allocations for investors concerned about rising inflation. During the 2021-2023 inflation spike, TIPS outperformed nominal Treasuries by approximately 7-15 percentage points annually. Build a bond ladder with TIPS →
International Inflation-Indexed Bonds
Other developed countries issue their own inflation-indexed bonds. The UK's Index-Linked Gilts adjust both principal and coupon payments using the Retail Prices Index (RPI) rather than CPI. Canada's Real Return Bonds (RRBs) use the Canadian CPI and pay a real yield set at auction. Germany's Bundeswertpapiere (Bunds) link to the Eurozone Harmonised Index of Consumer Prices (HICP). Japan's JGBi (Japanese Government Bond indexed to CPI) offers very low real yields because Japan has experienced minimal inflation for decades. International inflation-indexed bonds provide geographic diversification and can hedge against local inflation shocks. However, they introduce currency risk — if you buy UK Index-Linked Gilts and the British pound weakens against your home currency, returns are reduced. The WisdomTree International Inflation-Protected Bond ETF (IGLB) provides broad international exposure to inflation-indexed bonds from developed markets. Global fixed-income diversification strategies →
Are TIPS better than I Bonds?
TIPS and I Bonds serve different purposes. TIPS are better for larger allocations, institutional investors, and those who need liquidity, because they can be bought and sold in the secondary market in any quantity. I Bonds are better for individuals building a long-term inflation-protected savings pool because they offer tax-deferred growth, state and local tax exemption, and the ability to defer federal taxes until redemption. I Bonds have a $10,000 annual purchase limit per person, making them unsuitable for large portfolios. TIPS real yields fluctuate with market conditions and can go negative, while I Bonds have a fixed rate that never goes below zero. For most individual investors, a combination works: max out I Bonds each year ($10,000) and hold TIPS in retirement accounts for additional inflation protection beyond the I Bond limit.
How are TIPS and I Bonds taxed?
TIPS are subject to federal income tax but exempt from state and local taxes. However, there is a tax timing issue: the inflation adjustment to TIPS principal is taxable income in the year it occurs, even though you do not receive the principal adjustment until maturity. This makes TIPS in taxable accounts less efficient during high-inflation periods. Holding TIPS in tax-advantaged accounts (IRA, 401k) avoids this problem entirely. I Bonds offer better tax treatment: federal income tax on all interest is deferred until redemption, and the interest is exempt from state and local taxes. If you use I Bonds for qualified education expenses, the interest may be entirely federal tax-free (subject to income phaseouts). For taxable accounts, I Bonds are more tax-efficient than TIPS because of the deferral feature.
What happens to TIPS during deflation?
During deflation (falling prices), the inflation-adjusted principal of TIPS decreases. However, there is a deflation floor: at maturity, the Treasury pays you the greater of the inflation-adjusted principal or the original par value. This means you are guaranteed to get at least your original investment back at maturity, regardless of deflation. During the deflationary period of 2008-2009, TIPS principal adjustments were negative for several months, reducing the interest payments. However, because the overall inflation over the full term of the bonds meant the adjusted principal never fell below par at maturity, investors still received full principal plus accumulated interest. Short-term TIPS (VTIP) are less exposed to deflation risk than long-term TIPS because the deflation floor binds at each individual bond's maturity.
How much of my portfolio should be in inflation-indexed bonds?
Financial advisors typically recommend allocating 5% to 20% of a fixed-income portfolio to inflation-indexed bonds, with higher allocations for retirees and those living on fixed incomes. A common approach from Vanguard and BlackRock is to hold 50% of your bond allocation in nominal bonds and 50% in TIPS, particularly for retirement portfolios. This provides a hedge against both expected and unexpected inflation. Younger investors with long time horizons and high stock allocations may need less inflation protection because stocks historically outpace inflation over long periods. Retirees who rely on portfolio income should weight more heavily toward TIPS to protect purchasing power. A conservative portfolio might hold 30% stocks, 35% nominal bonds, 30% TIPS, and 5% cash or I Bonds.