Inflation at 3.7%: How I Bonds and TIPS Can Protect Your Savings

Your savings account just got a rival you cannot ignore: the price tag on everything else. According to the Bureau of Labor Statistics, consumer prices were up 3.7% over the 12 months ending in September 2026. If the cash you hold earns less than that, you are quietly losing buying power every month, even while the balance on your statement looks fine.

The good news is that Washington sells two products built specifically for this problem. They are not exotic, they are not complicated, and you can buy them directly from the Treasury. This guide explains how I bonds and Treasury Inflation-Protected Securities (TIPS) work, where each one shines, and how to decide how much of your cash belongs in either.

What the September inflation report actually showed

The BLS release, published on October 14, 2026, put the all-items Consumer Price Index up 0.6% for the month (seasonally adjusted) and 3.7% from a year earlier. The mix underneath the headline matters, because it tells you what kind of inflation households are living with.

• Energy: up 5.2% in the month and 20.4% over 12 months.
• Gasoline: up 9.1% in the month (seasonally adjusted) and 34.2% over 12 months.
• Shelter: up 0.4% in the month and 3.2% over 12 months.
• Food: flat for the month and up 2.5% over 12 months.
• Core CPI (excluding food and energy): up 0.3% in the month and 2.6% over 12 months.

In plain English, the headline is being pushed hard by fuel. Core inflation is meaningfully lower. That gap is useful: it suggests the pressure is concentrated rather than everywhere at once, but it does not change the fact that your personal cost of living probably moved more than the core number if you drive a lot.

Why cash is the quiet loser when prices rise

Inflation is a tax on anything that stays the same size. A dollar in a checking account does not shrink on paper, but it buys less groceries, gas and rent next year than it does today. What matters is your real return: the interest you earn minus the inflation rate.

If your account pays 4% and prices rise 3.7%, your real return is roughly 0.3%. If it pays 1% you are going backwards. And because interest is usually taxable, the after-tax picture is a little worse still.

This does not mean you should empty your emergency fund into anything fancy. Cash exists to be there, not to win. It means the money you will not need for several years deserves a second look.

Option one: I bonds, the set-and-forget shield

Series I savings bonds are issued by the U.S. Treasury and sold through TreasuryDirect. Based on the Treasury’s own comparison page, here is how they work:

• The earnings rate combines a fixed rate with a semiannual inflation rate based on CPI-U. New rates are announced in May and November.
• You can buy up to $10,000 per Social Security number per calendar year electronically, with a $25 minimum.
• They run for 30 years, but you can redeem after 12 months. Redeem before five years and you forfeit three months of interest.
• Interest accrues and is paid when you redeem. It is subject to federal tax, which can be deferred until redemption, and exempt from state and local income tax.
• They are non-marketable. You cannot sell them to another investor; you can only redeem them with the Treasury.

The appeal is simplicity. There is no price to watch and no market risk, and the inflation adjustment is built in. The drawbacks are the annual cap, the one-year lockup and the early-redemption penalty. Because the rate resets twice a year, your return follows inflation with a lag rather than perfectly in real time.

Check TreasuryDirect for the current fixed rate before buying, since that component is set at purchase and stays for the life of the bond.

Option two: TIPS, the marketable alternative

Treasury Inflation-Protected Securities work differently. According to the same Treasury comparison:

• The principal rises or falls with CPI-U, published monthly. Interest is paid semiannually at a rate set at auction, and it is calculated on the adjusted principal.
• Terms are 5, 10 or 30 years, with a $100 minimum in $100 increments.
• Non-competitive bids can go up to $10 million, so there is no practical cap for most households.
• Federal tax applies in the year interest payments and inflation adjustments occur, though TIPS are exempt from state and local income tax.
• Principal decreases if deflation occurs.
• They are marketable, so you can sell before maturity in the secondary market.

That tax detail trips people up. In a taxable account you can owe tax on inflation adjustments you have not received in cash yet, sometimes called “phantom income.” Many investors therefore prefer holding TIPS inside an IRA or 401(k), or through a fund or ETF in a tax-advantaged account.

The other catch is price risk. If you sell before maturity, the market price can be higher or lower than what you paid, because it responds to changes in real yields. Hold to maturity and you are mostly insulated; sell early and you are exposed.

I bonds vs. TIPS at a glance

• Buying limit: I bonds $10,000 a year per person; TIPS effectively unlimited for ordinary savers.
• Liquidity: I bonds locked for 12 months with a three-month interest penalty before five years; TIPS can be sold anytime at market price.
• Inflation link: I bonds reset twice a year; TIPS principal adjusts monthly.
• Tax timing: I bond interest can be deferred; TIPS adjustments are taxed as they occur.
• Market risk: I bonds none; TIPS yes if sold before maturity.

Neither is clearly better. They are tools for different jobs. I bonds suit a modest pot of money you can ignore for five years. TIPS suit larger amounts, retirement accounts, or investors who want to build a ladder of maturities matched to future spending.

A worked example

Imagine Maria, 52, has $60,000 in a savings account earning 4%. She keeps $25,000 as an emergency fund and has $35,000 she will not touch for at least five years.

She decides to buy the $10,000 I bond maximum this year. She then puts $15,000 into a TIPS ladder inside her IRA, with equal amounts maturing in five years and ten years, and keeps the remaining $10,000 in cash for near-term goals.

Notice what she did not do. She did not touch her emergency fund, she did not bet on a forecast, and she did not chase yield. She simply moved money she does not need soon into assets whose payouts are linked to the same index that drives her cost of living. If inflation speeds up, those holdings adjust. If it fades, she gives up little. The numbers here are illustrative, not a recommendation.

Common mistakes to avoid

• Buying I bonds with emergency money. The 12-month lockup and the penalty make them poor for cash you might need.
• Ignoring taxes on TIPS. Hold them in a tax-advantaged account where you can.
• Chasing the headline. A high inflation print does not mean next year’s inflation will be high. These assets protect you either way, but do not overpay in expectation of a spike.
• Forgetting the personal rate. Your own inflation depends on what you buy. Fuel-heavy budgets feel a number like 34.2% on gasoline far more than the core rate suggests.
• Going all in. Stocks, real assets and a paid-down mortgage can also protect against inflation. Diversify.

Frequently asked questions

Can I lose money on an I bond?

You cannot lose principal to market swings because I bonds are not traded. If you redeem within five years, you give up three months of interest, which can reduce your gain.

Do TIPS pay off if inflation falls?

TIPS principal moves with CPI-U in both directions, so if prices decline, principal decreases. Your return then depends on the fixed rate set at auction and on how long you hold.

Should I replace my savings account with these?

No. Keep an emergency fund in accessible cash. Consider I bonds or TIPS only for money you can leave alone for years.

Sources: U.S. Bureau of Labor Statistics CPI release for September 2026, as posted by the U.S. Department of Labor (https://www.dol.gov/newsroom/economicdata/cpi_10142026.pdf); U.S. Treasury, Comparison of TIPS and Series I Savings Bonds (https://savingsbond.gov/indiv/products/prod_tipsvsibonds.htm).

This article is for educational purposes only and is not personalized investment, tax or legal advice. Consult a qualified professional before making financial decisions.