I Bonds Explained: The Government Savings Bond That Fights Inflation

There's a savings product backed by the U.S. government, paying an interest rate that moves with inflation, with zero risk of losing your principal — and most people have never heard of it. Series I savings bonds, or I bonds, are the quietest good deal in personal finance. Here's how they actually work and where they fit.

An I bond is a bond you buy directly from the Treasury at treasurydirect.gov — not through a bank or broker. You can buy as little as $25 and up to $10,000 per person per year (plus another $5,000 if you direct your tax refund into paper bonds). The interest rate has two parts: a fixed rate that stays for the life of the bond, and an inflation rate that resets every six months based on the Consumer Price Index. When inflation runs hot, the combined rate can look spectacular — it hit 9.62 percent in 2022, which is why I bonds briefly went viral. When inflation cools, the rate drops. The fixed portion has recently been around 1 percent, which means you're guaranteed to beat inflation by that margin no matter what.

The tax treatment is the sleeper feature. I bond interest is exempt from state and local income tax entirely — a bigger deal than it sounds if you're in a high-tax state. Federal tax is deferred until you cash out, so the interest compounds untouched for up to 30 years. And if you use the proceeds for qualified education expenses, the federal tax can be exempt too, with some income limits. Compare that to a high-yield savings account, where every dollar of interest is taxed as ordinary income every single year in the year you earn it.

Now the catches, because there are always catches. First, you can't touch the money for 12 months — full lockup, no exceptions, not even for emergencies. Second, if you cash out before five years, you lose the last three months of interest as a penalty. Third, the $10,000 annual cap means this is a slow-build tool, not a place to park a windfall. A couple can buy $20,000 a year plus the tax-refund trick, so a household can build a meaningful position over a few years, but one person maxes out fast.

So where do I bonds fit? They're not an emergency fund — the 12-month lockup disqualifies them. They're not a growth investment — stocks will beat them over long periods. Their lane is the 1-to-5-year savings goal: the house down payment you're building, the car fund, the "I want this money safe but I hate watching inflation eat it" bucket. For money with a timeline in that range, I bonds beat high-yield savings accounts in most environments because the rate tracks inflation automatically — you never have to chase the best bank promo again.

Run a quick comparison. You put $10,000 in a high-yield savings account at 4 percent. After a year you have $10,400, and you owe tax on the $400 — at a 22 percent federal rate plus state tax, you keep maybe $290 of it. The same $10,000 in I bonds during a year when the composite rate averages 4 percent: you have $10,400, you owe zero tax until you cash out, and zero state tax ever. The headline rates look identical; the after-tax reality favors the bond. And if inflation spikes to 7 percent, the savings account stays at 4 while the I bond climbs — that's the whole point.

There's one more use case worth knowing: I bonds as a second-tier emergency fund. Financial planners sometimes suggest that once your primary emergency fund is full, additional safety-net money can go into I bonds — after the first year, they're redeemable anytime with only the three-month penalty before year five, they're inflation-protected, and they can't lose value. Money you might need in year two or three but probably won't is exactly what I bonds are for.

The mechanics are clunky — TreasuryDirect looks like a website from 2002, because it basically is one. Setting up the account takes some patience, and the interface will test yours. But the product underneath is genuinely good: government-backed, inflation-proof, tax-advantaged savings with no fees. In a world of savings accounts that quietly pay you less than inflation while taxing every penny, the I bond is the rare product that's actually on your side.

Disclosure: This article was drafted with AI assistance and reviewed by the author.