I-Bonds

I-Bonds are a unique type of U.S. government savings bond designed specifically to help individual investors protect their savings from inflation. Unlike most other bonds, I-Bonds offer a combination of a fixed interest rate and a variable rate that adjusts with inflation. This makes them especially appealing during periods when the cost of living is rising. However, I-Bonds come with specific purchase limits and other constraints that shape how you can use them in your portfolio.

The way I-Bonds accrue interest is a bit different from traditional bonds. The interest is compounded semiannually and is based on a combination of a fixed rate and an inflation rate. The formula for the composite rate, which determines how much your I-Bond earns, is:

Interest accrues monthly, but is compounded every six months. You do not receive regular interest payments; instead, the value of your I-Bond increases and you receive all the accrued interest when you cash it out.

I-Bonds are most useful in a portfolio when you want a safe, government-backed investment that keeps up with inflation. They’re especially valuable for medium- to long-term savings goals where protecting your purchasing power is important, such as building an emergency fund or saving for a future expense that’s several years away. Since the interest is exempt from state and local taxes, and federal taxes can be deferred until redemption, I-Bonds can also offer tax advantages for some investors.

Despite their advantages, I-Bonds come with several limitations. The annual purchase cap means you cannot use them as your sole fixed income investment if you have a large portfolio. You must hold I-Bonds for at least one year, and if you cash them in before five years, you forfeit the last three months of interest. You can’t buy them in retirement accounts, and they are not tradable or transferable like other bonds or securities. Because of these restrictions, I-Bonds are best used as a supplement to your core bond holdings, not a replacement. They are ideal when you want to protect a portion of your cash from inflation, but not suitable if you need immediate liquidity or want to invest large sums in inflation-linked assets.