Series I bonds mature in 30 years and are designed to earn interest and protect investors from inflation.  As of May 2022, the initial interest rate was 9.62% through October 2022, the highest since it was introduced in 1998 as a result of inflation. That is a combination of a 0% fixed rate and an inflation rate of 9.62%. Series I bonds can only be purchased directly from the U.S. Department of the Treasury in two ways: through TreasuryDirect.gov or by using your federal income tax refund. Learn how the buying process works, what the limits are, and when you should consider I bonds.

How Buying Series I Savings Bonds Works

Series I bonds can be purchased in two forms: electronic and paper. I bonds are purchased at the face value. Interest accrues to the bond monthly, and interest is compounded twice per year.

Types of I Bonds

You can buy electronic I bonds online through the U.S. Department of the Treasury site TreasuryDirect.gov. Electronic bonds are registered and tracked entirely online, and there is no physical certificate. You can buy electronic bonds with any money, but paper I bonds can only be bought with your income tax refund.

I Bond Minimum Purchase

You can only buy a limited amount of I bonds. Electronic I bonds have a maximum limit of $10,000 per year, and paper bonds that use your tax refund have a maximum limit of $5,000. The total limit for series I bonds is $15,000.

Selling Your I Bonds

Series I bonds can only be cashed in. They can’t be sold on the secondary markets. I bonds can be cashed in anytime after the first 12 months, but there is a penalty of the previous three months’ worth of interest if the bond is less than five years old.

Buying Series I Bonds Through TreasuryDirect

The first step for buying I bonds electronically is to open a TreasuryDirect account. Go to TreasuryDirect.gov and select “open an account.” You’ll need your Social Security number, driver’s license or other state-issued ID, and banking information. After you have completed the application, you can make a purchase. Go to the “BuyDirect” tab and select “Savings Bonds.” Complete the specifics of the buying process according to your needs.

The Bottom Line

Series I bonds are a low-risk, convenient way to invest your money and add an inflation hedge to your portfolio. The limits to how much you can invest in I bonds apply to  individual Social Security numbers. So families can potentially put aside considerably more than the individual limit. I bonds also offer tax benefits. I bond interest is exempt from state taxes, and federal income tax isn’t paid until the bond is cashed in. Taxpayers may be able to exclude a portion of I bond interest if it is used for education expenses. Want to read more content like this? Sign up for The Balance’s newsletter for daily insights, analysis, and financial tips, all delivered straight to your inbox every morning!