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Series I Savings Bonds – What They Are and How to Buy Them

For many years, the financial crisis of the late 2000s left a persistent legacy: stubbornly low interest rates on low-risk, low-reward investment vehicles. Rates on savings accounts, money market funds and government bonds remained at or below the rate of inflation basically through the 2010s, and interest rates on consumer-facing mortgages and auto loans remained historically low as well. This was a massive tailwind for the American economy as consumers and businesses tried to repair the damage wrought by the crisis.

But it’s an increasingly distant memory, undone by trillions in pandemic stimulus that drove inflation to levels not seen in 40 years and forced the Federal Reserve to rapidly increase interest rates. Savings account yields jumped in response, rewarding those able to save, while overinflated prices for riskier assets like crypto and tech stocks fell back to earth.

By design, one particular investment has performed remarkably well during this otherwise volatile period: the Series I savings bond. It’s an inflation-protected bond issued by and backed by the full faith and credit of the United States government, and its returns often (though not always) exceed those on the best high-yield savings accounts.

What Are Series I Savings Bonds?

Series I savings bonds are Treasury bonds, which means they’re among the safest investments around. The Treasury Department describes them as “low-risk, liquid savings products.” While there’s no such thing as a completely safe investment, it’s worth noting that the U.S. government has never defaulted on its obligations to bondholders.

Unlike T-bills, Series I bonds don’t come with frustratingly long terms or high minimum investment requirements. On the other hand, they may not offer the competitive returns of some investment-grade municipal bonds. As zero-coupon investments, Series I certificates don’t issue interest in periodic payouts; instead, the interest that each security accrues is added onto its cash-out value. When you sell a Series I bond, you receive a lump sum that includes the principal amount and all accrued interest.

Buyers typically hold Series I bonds for at least five years, but they can be cashed out after the first year if you’re willing to pay a small penalty. Their interest rates are determined by combining a “fixed” and “inflation” rate to arrive at a “composite” rate.

When you buy your bond, you lock your fixed rate – currently set at 0.9% – in for its entire term, while your inflation rate changes every six months, in May and November. The current composite rate is set at 4.30%.

Differences Between EE and I Savings Bonds

The Series I bond is often compared to the Series EE savings bond, another nontraditional Treasury vehicle. But there are some important practical differences between the two:

  • Interest rates: The most notable difference between EE savings bonds and I savings bonds is their interest rates. Whereas I-bond rates are calculated by adding a predetermined fixed rate to a variable inflation rate that readjusts every six months in response to the Consumer Price Index for Urban Consumers (CPI-U), EE-bonds issued after 2005 offer fixed rates of return that are competitive with prevailing rates for five-year Treasury bonds. Translation: a much lower rate.
  • Paper bonds: The Treasury has stopped selling paper EE-bonds. If you want to own a Series EE bond, you need to purchase it through the Treasury’s online TreasuryDirect portal and hold it electronically. It’s still possible to buy paper I-bonds with your tax refund, and doing so allows you to buy up to $5,000 more per year (for a total of $15,000 rather than $10,000).

One thing Series I and EE bonds have in common is the fact that they’re issued in much smaller tranches than traditional T-bills. You can buy I-bonds and EE-bonds for as little as $25. After the $25 threshold, both types of bonds can be bought in increments of a single penny. I-bonds and EE-bonds both offer similar tax advantages.

Basic Structure

Series I savings bonds are low-risk, relatively low-interest vehicles that are meant to be held for years. If your bond’s principal amount is $5,000, you’ll receive $5,000 plus interest when you sell out, regardless of what the bond market has done in the intervening period.

Interest Rates

An I-bond’s composite interest rate is calculated in two parts:

  • Fixed rate. This rate is calculated semi-annually, on the first business days of May and November. However, when you buy an I-bond, your fixed rate remains in force for the life of the bond. It’s currently set at 0.0%, but it has been much higher in the past.
  • Variable inflation rate. This rate also changes semiannually, in May and November. Changes to this rate always affect issued bonds, so bondholders can expect to see their composite rates shift twice per year. The variable rate is equal to the CPI-U’s rate of change over the preceding six months. At the moment, this rate of change is 3.45%.

To determine the actual composite interest rate, the Treasury Department uses the following formula:

composite rate = [fixed rate + (2 x inflation rate) + (fixed rate x inflation rate)]

Currently, this equation looks like this:

[.90 + (2 x .0169) + (.00 x .0169)] = .90 + .0338 + 0.0000000 = .0430 = 4.30%

The previous month’s share of interest accrues to an I-bond’s existing balance on the first day of each month, but said interest is only compounded on a semiannual basis. In other words, the bond’s paper value increases each month, but this merely reflects the addition of one-sixth of the previous period’s interest.

This arrangement is designed to increase the liquidity of these securities and make month-by-month redemptions more attractive. At current interest rates, the face value of your bond – plus all the interest it had accumulated prior to the most recent compounding date – would increase by about 0.12% per month.

Maturity, Redemption, and Other Restrictions

Before you buy an I-bond, understand its restrictions and limitations:

  • Purchase restrictions. Currently, you can buy electronic I-bonds worth a total of $10,000 in a calendar year. If you wish to purchase paper I-bonds with your tax refund, you’ll be limited to a total purchase of $5,000 per year. You must buy bonds worth at least $25 in a single purchase.
  • Maturity. I-bonds initially mature 20 years after their issue date, but the Treasury Department offers bondholders the option to renew their bonds for an additional 10 years.
  • Redemption restrictions. An I-bond must be held for at least 12 consecutive months; the government simply doesn’t allow bondholders to redeem their securities before then. Once you hit the one-year mark, you can redeem, but you’ll forfeit three months’ interest if you redeem before year five. That’s comparable to the interest penalty on longer-term CDs.
  • Redemption process. You can redeem electronic I-bonds through the U.S. Treasury’s TreasuryDirect portal. Many banks are happy to redeem paper I-bonds. I-bonds aren’t tax-exempt, but you may pay less tax on the interest than on interest from private bank accounts.

Tax Issues

You must pay federal income tax on your I-bonds’ interest payments, but they may be exempt from state and local income taxes. If you receive bonds as a gift or inheritance, you may be required to pay federal and/or state gift tax, estate tax, or excise tax on their interest.

If you use your bonds to fund educational expenses for your child (or another dependent), you may be able to avoid federal income taxes. You must use your bonds’ principal and interest for qualifying expenses, including tuition and course fees, and your chosen higher education institution must be eligible for federal loan assistance.

Regardless of whether you use your bonds to finance your child’s education or your own, you must be at least 24 years old when you purchase the bonds to qualify for the tax benefit. Bonds purchased before you turn 24 don’t under any circumstance accrue education-related tax benefits. And you must meet certain income requirements.

Since I-bonds are a long-term investment, how you report your interest payments can have an effect on your overall tax burden. There are two methods for doing so:

  • The accrual method. This allows you to report each bond’s interest in annual increments for every year between its issue date and maturity date. For instance, if you hold your bond from December 2022 until October 2032, you’ll pay taxes on all 11 returns during that period. The accrual method spares you a big tax bill at the time of maturity, but it does render you liable for tax payments on income that you can’t yet access.
  • The cash-out method. Rather than reporting your interest income in annual installments, this method allows you to wait until your maturity date and report your entire interest haul in one lump sum. You’ll be taxed at your federal income tax rate during the year in which you redeemed the bond – in the above example, 2032, not 2022.

Eligibility Requirements

Historically, Series I savings bonds have been reserved solely for individual purchasers. In 2009, the rules governing I-bond ownership were relaxed to let most corporations – including limited liability firms and S-corps, as well as most trusts and partnerships – into the fold. This type of security now represents a crucial inflation hedge for many small businesses that lack access to favorable credit terms.

I-bonds are available to anyone who meets at least one of these criteria:

  • U.S. citizens, including citizens residing abroad
  • U.S. government employees, regardless of location or citizenship status
  • U.S. citizen minors

This last eligibility class is very nearly unique. Unlike most other securities, including stocks, corporate bonds, and T-bills, minors can directly own I-bonds without using a trust as an intermediary. While minors can’t directly buy bonds using their own TreasuryDirect accounts, they can use custodial accounts that are linked to their guardians’ main accounts.

Those guardians must actually pull the trigger on bond purchases, but each bond is deposited directly into the minor’s custodial account. Of course, there’s nothing stopping minors from being in the room when their guardians make these purchases, and it’s actually a great opportunity to teach your kids about a financial instrument other than your standard checking or savings account.

Advantages of Series I Savings Bonds

Why buy I-bonds? These are some of the most powerful arguments in favor.

1. Protection Against Inflation

I-bonds boast a built-in hedge against inflation. When interest rates are low, this hedge isn’t spectacular – from 2010 to 2021, the Consumer Price Index-chained inflation adjustment has exceeded 2% for just one six-month period. For most of that time, it was stuck well below 2%. Then again, the annual inflation rate didn’t surpass 2% between 2007 and 2021, an even longer timespan.

Even if I-bonds don’t beat inflation by a wide margin, the fact that their rates fluctuate in response to on-the-ground inflation pressures is a big deal. Contrast this built-in protection with that of a 10-year T-bill. At the moment, the 10-year T-bill yields about 3.6%. That’s significantly below the current inflation rate of about 6%, which means the 3.6% T-bill actually has an inflation-adjusted yield of about -2.4%. Meanwhile, newly issued I-bonds sport starting interest rates of 6.89%, more or less matching annual price increases.

Since this instrument’s rates are designed to rise in response to inflationary pressures – regardless of prevailing rates at the time of issue – even bonds purchased before said period of inflation would be protected against soaring prices. By contrast, T-bill buyers are stuck with the same interest rate for the decade-long lifespan of their bond, no matter what happens to consumer prices during that time. For conservative investors, the choice is clear: An inflation-protected, but still safe, bond like the Series I offers significant benefits over fixed-rate-only securities like 10-year T-bills.

2. Clear Tax Benefits

Since they’re issued by the federal government, I-bonds aren’t subject to state or local taxes. Additionally, the flexible tax reporting methods – accrual and cash-out – allow you to choose how you’ll be taxed on your interest income. For example, if you’d prefer to avoid a big tax bill for the year in which you redeem your bonds, you can use the accrual method to spread the cost over many years. If you’d rather not pay tax on income that you can’t yet access – after all, I-bond interest is plowed right back into the bonds’ face value on a semiannual basis – you can defer the pain with the cash-out method.

I-bond holders who use their bonds’ principal and interest payments to cover qualifying educational expenses can avoid federal taxation, provided that they meet certain income requirements and purchase the bonds after they turn 24.

3. Long-Term Security

I-bonds are backed by the full faith and credit of the federal government. That alone should be a powerful argument for their safety, but their dowdiness offers an additional layer of security. I-bonds – with their $10,000 annual buying limit – simply can’t be purchased in large enough tranches to attract institutional buyers, market-makers, or other players who might act as destabilizing influences.

Short sellers who dabble in bonds avoid I-bonds in favor of vehicles with laxer purchasing limits, and the mandatory 12-month holding period keeps short-term investors out of the space. As an I-bond buyer, you won’t have to worry about risk-seeking players ruining your carefully laid investment plans.

4. Flexibility and Liquidity

Unlike regular Treasury bonds, corporate bonds, and some other fixed-income securities, Series I savings bonds are both flexible and liquid. For evidence of the former, look to this vehicle’s rock-bottom minimum-purchase value of $25 and its razor-thin buying increments of one cent. For confirmation of the latter, refer to its relatively short 12-month holding period and its manageable three-month interest penalty for short-term holdings. Every I-bond comes with a 20-year maturity period and an optional 10-year extension, but these figures are mere benchmarks – you shouldn’t feel obligated to hold onto your bonds for decades.

5. Educational Benefits

If you commit to using your I-bonds to fund certain educational endeavors, you may avoid federal taxation on your earnings. To do so, you must prove that you were at least 24 years old when you purchased the bonds and that you spent said earnings on qualifying educational expenses for yourself, your dependents, or your spouse. These typically include:

  • Tuition costs for any courses required for a specific degree or certification
  • Costs related to certain prerequisite, supplemental or laboratory courses

These tax benefits typically don’t extend to the cost of textbooks, activity fees, room and board expenses, athletics, and other nonessential expenses.

Disadvantages of Series I Savings Bonds

I-bonds have some notable downsides. Consider them before you buy.

1. Annual Purchase Limits

If you’re hoping to move your life savings into a more conservative type of security, you’ll have to look elsewhere. For individual holders, the Treasury Department limits electronic I-bond purchases to $10,000 per year, and paper purchases to just half that. It adds up to a grand total of $15,000 per year. If you earn good money and can save a decent amount of it each year, this is probably enough to serve as a sizable but not overwhelming slice of your portfolio.

By comparison, the feds cap a single individual’s purchases of electronic TIPS – Treasury Inflation-Protected Securities, which accrue interest at a fixed rate that typically exceeds the rate of inflation – are capped at $5 million per auction. This upper limit is obviously out of reach for regular folks, but the distance between $10,000 and $5 million is great. Even a $50,000 or $75,000 cap would help well-off but not truly “rich” people.

2. Restrictions on Educational Uses

I-bonds are useful for college savers, but their educational tax benefits do come with some restrictions. To avoid federal taxes on bonds purchased for this purpose, you need to mind these caveats:

  • I-bonds purchased before your 24th birthday are automatically subject to federal taxation. You can use bonds purchased before this date to fund your child’s education, but you must pay taxes upon redemption, so there’s no compelling reason to do this. After your 24th birthday, you can set aside I-bond purchases for tax-free tuition for your child or legal dependent. You can also buy I-bonds to fund your own education, but they must be registered in your own name. And again, you must purchase the applicable bonds after you turn 24.
  • If you fail to use an I-bond’s funds for tuition during the calendar year in which you redeemed it, you’ll forfeit your tax benefits. In other words, you should wait to redeem education-designated I-bonds until you actually receive a tuition bill.
  • If you’re married, you must file a joint return to qualify for these education tax advantages.
  • Your chosen institution of higher education must be eligible for the federal guaranteed student loan program and other forms of federal financial aid.
  • Your income can’t exceed Treasury-set eligibility limits. These figures change each tax year, but they’re generally set above the median income figure for both individual and joint filers.

3. Highly Variable Returns

Although Series I bonds’ earning power is inflation-protected, these securities won’t make you rich. With inflation at historical lows in the early 2010s, I-bonds earned an annual return of little more than 1%. This was just over half the rate of return on the 10-year T-bill, which is often regarded as the benchmark for fixed-rate, low-risk securities.

Then again, I-bonds’ inflation protection is clear in the more inflationary environment of the early 2020s, where the return modestly exceeds the inflation rate. T-bills, meanwhile, continue to lag inflation.

4. No Bidding Framework for Investors

When you buy an I-bond, you know what you’re getting. For some investors, this is probably a good thing. For others, it leaves out an essential piece of the investing puzzle: the profit motive. Since you can’t bid on your initial purchase of an I-bond and can’t rely on fluctuations in value to pad your margins, your bond’s interest rate serves as your sole source of return. While the inflation-adjusted component of said interest rate offers some opportunity for growth, you shouldn’t expect eye-popping returns.

By contrast, you can bid your heart out for electronic TIPS. For regular investors, bidding for TIPS is noncompetitive; you must accept the rate that the Treasury Department determines at the start of each auction.

Like I-bond rates, though, rates on TIPS are calculated according to the prevailing rate of inflation. Better, the noncompetitive bidding system guarantees that you’ll receive the exact security, in the exact quantity, that you requested. You won’t be muscled out by more experienced investors.

How to Invest

There are two ways to buy and hold Series I savings bonds:

TreasuryDirect is administered by the U.S. Treasury Department and is available on a 24-7 basis. When you buy through this portal, you agree to accept a secure online account in place of an old-fashioned bond certificate. While you won’t have the satisfaction of holding a valuable piece of paper, you also won’t have to worry about losing your bond. (Although, as registered securities, I-bonds are impossible to lose – after verifying your identity and buying history, the Treasury Department will happily replace lost certificates.)

If you want to buy multiple, small-value bonds over the course of a year, TreasuryDirect also lets you set up a recurring purchase schedule or snag electronic bonds directly via a payroll deduction program known as the Payroll Savings Plan. Neither tool is available to you if you hold paper bonds only, but you can purchase both electronic and paper I-bonds with your federal tax refund.

Final Word

Series I savings bonds offer impressive tax advantages, decent rates of return for guaranteed investments, and some protection against inflation. They’re also flexible, liquid, and easy to purchase or sell. On the other hand, I-bonds come with frustrating restrictions that may alienate seasoned investors or folks who have plenty of money to burn.

The bottom line: They’re not for everyone, but they do have an important role to play in a balanced, fundamentally conservative portfolio. If you think they make sense for your needs, give them a try – it’s not like you’ll lose money on the deal.

Brian Martucci writes about credit cards, banking, insurance, travel, and more. When he's not investigating time- and money-saving strategies for Money Crashers readers, you can find him exploring his favorite trails or sampling a new cuisine. Reach him on Twitter @Brian_Martucci.

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