Comparing I Bonds to Treasury Inflation Protected Securities

The Subtle yet Distinct Differences Between I Bonds and TIPS

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I Bonds vs. TIPS. Here's a comparison of the two. Henrik Sorensen / Getty Images

Both I Bonds and treasury inflation protected securities, also called TIPS, offer principal protection and purchasing power protection. They each have built-in features to combat rising inflation risks, but they do it in different ways.

This comparison of the differences between TIPS and I Bonds can help guide you when you're making a decision as to what type of investment is best for you. 

Purchasing Caps

The number of electronic I Bonds you can buy in a single calendar year is capped at $10,000 per person as of 2017.

You can buy an additional $5,000 in paper bonds if you direct your tax refund toward the purchase. There's a $25 minimum and it can be to the penny, such as $25.99. 

You can buy up to $5 million in TIPS at any single auction using Treasury Direct. There's a $100 minimum. 

Minimum Terms of Ownership

TIPS have no minimum term of ownership. You can sell them on the secondary market at any time.

You can't sell I Bonds until 12 months after you purchase them, and you'll forfeit three months' interest if you redeem them before you've owned them for five years.

Tax Treatment

Interest and any increase in principal from inflation adjustments are taxed each year when you buy TIPS. You can be taxed on income you haven't received yet because you don't receive an increase in the principal of the bond until you sell it. This feature makes it more tax-efficient to own TIPS in tax-deferred retirement accounts.

Interest is added to the value of an I Bond and only taxed upon redemption.

Both TIPS and I Bond interest are subject to federal income tax, but it's typically tax-exempt for the purpose of state and local taxes.

Performance During a Time of Deflation

TIPS can go down in value in a deflationary environment but they'll always be worth at least the original principal amount at redemption.

I Bonds can never go down below the bond's value in the prior month. Any upward inflation adjustments you've received can't be eroded by a period of later-occurring deflation.

Available Terms

TIPS are issued in 5-, 10- and 30-year terms.

I Bonds pay interest for 30 years. You can redeem them after 12 months.

How the Inflation Adjustment Works

TIPS principal is adjusted by changes in the consumer price index, either up or down. The interest rate is determined at issue. The dollar amount paid will depend on the principal value of the bond so a higher amount of interest will be paid out if the principal is adjusted upward based on increases in inflation.

The variable portion of an I Bond's interest rate is set every six months. It's based on the consumer price index. This variable rate is paid out in addition to a fixed rate that is determined when the bond is issued.

Where to Buy and Keep These Investments

TIPS can be purchased online through Treasury Direct or from a bank or broker. You can use a noncompetitive bid and take the market yield. If you go through a bank, broker, or dealer, you can make a competitive bid to specify your desired rate, but you might not get want you want.

I Bonds are only available online through Treasury Direct.