Treasury Bonds vs. I-Bonds: Where Should You Park Your Safe Money Right Now?

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What Are Treasury Bonds and Series I Savings Bonds?

The debate over treasury bonds vs I-bonds often gets framed as a simple rate comparison, but the two instruments work very differently at a mechanical level. A Treasury bond (or T-bond) is a marketable, fixed-rate debt security issued by the U.S. Department of the Treasury with a maturity of 20 or 30 years. You can buy and sell it on the secondary market any business day, and its nominal coupon rate never changes. A Series I savings bond (I-bond) is a non-marketable savings bond, also government-backed, whose interest rate resets every six months based on official consumer price index data. They are both among the safest instruments in existence. That is where the similarity ends.

Treasury securities also include shorter-duration products: Treasury bills (T-bills) mature in four, eight, thirteen, seventeen, twenty-six, or fifty-two weeks; Treasury notes (T-notes) mature in two, three, five, seven, or ten years. When most people compare day-to-day safe parking options, they are looking at T-bills or 2-to-10-year T-notes alongside I-bonds, not 30-year bonds. This article uses “Treasury securities” to cover the full family and distinguishes the specific duration where it matters.

How I-Bonds Actually Work

I-bonds are purchased exclusively through TreasuryDirect.gov, the U.S. Treasury’s direct retail platform. Each bond carries two rate components: a fixed rate set at purchase that never changes for the life of the bond, and a variable inflation rate adjusted every May and November based on the prior six months of CPI-U data. The composite rate formula is: fixed rate + (2 × semiannual inflation rate) + (fixed rate × semiannual inflation rate). That last term is small, but it matters over decades.

One feature that gets overlooked: I-bonds have a contractual floor of 0%. The composite rate cannot go negative, even if CPI registers deflation. That zero-floor guarantee is not available on any nominal Treasury security. It is a genuine form of downside protection, though in practice the U.S. has experienced meaningful deflation in only a handful of brief stretches since World War II.

How Treasuries Actually Work

Marketable Treasuries pay a fixed coupon (or, in the case of T-bills, are sold at a discount to face value). The yield you earn is locked in at purchase if you hold to maturity. If you sell early and rates have risen since you bought, you sell at a loss. If rates have fallen, you sell at a gain. That secondary-market price sensitivity is both a feature and a risk. For someone who needs flexibility and has no specific maturity date in mind, rolling short-term T-bills is a popular strategy: lock in current yields for weeks or months at a time, then reassess.

Current Rates in March 2026: Where the Numbers Actually Stand

The rate picture in March 2026 is closer than the 2022-era headlines suggested it would be. I-bonds issued from November 2025 through April 2026 carry a composite rate of approximately 4.03%, consisting of the 0.90% fixed rate plus an inflation component based on the September 2025 CPI reading. The next rate announcement comes in May 2026: bonds issued from May 1 through October 31, 2026 will carry a composite rate of 4.26%, still anchored by that 0.90% fixed base.

On the Treasury side, 3-month T-bill yields sit near 3.7% and 10-year T-notes yield roughly 4.3%. The Federal Reserve has held its policy rate in restrictive territory through early 2026, keeping short-duration yields elevated by historical standards. At these levels, a 2-year T-note offers a known, locked-in return for exactly 24 months, no rate resets, no surprises, full liquidity through the secondary market after purchase.

A Quick Worked Example: $10,000 Over 12 Months

Put $10,000 into an I-bond issued in May 2026 at 4.26% composite. After 12 months, you would have earned roughly $426 in interest. That same $10,000 in a 3-month T-bill rolling at 3.7% would yield approximately $370 over the same period, assuming the rate holds steady across four renewal cycles. The 10-year T-note at 4.3% would gross $430. The gap between the I-bond and the 10-year T-note is small: about $4 on $10,000. But the 10-year T-note exposes you to interest rate risk if you need to exit early, while the I-bond exposes you to a 12-month liquidity lockup.

Neither option is obviously wrong. The right answer depends on what you actually need the money to do.

How Returns Are Calculated and Protected

The mechanics behind I-bond returns are worth understanding precisely because they create a fundamentally different risk profile than any fixed-rate instrument. Every six months, the Treasury announces a new semiannual inflation rate derived from the change in the non-seasonally-adjusted Consumer Price Index for All Urban Consumers (CPI-U). That percentage, doubled and added to your fixed rate, becomes your next six-month composite rate. If CPI falls sharply, your rate falls, but never below zero.

The Fixed Rate Is the Sleeper Variable

Most I-bond coverage fixates on the variable inflation component, but the fixed rate deserves equal attention. The Treasury sets it each May and November. For bonds issued from May 2026 onward, the fixed rate stands at 0.90%. That 0.90% is locked in for the entire 30-year life of any bond purchased before the next reset. If inflation moderates and the next round of Treasury fixed-rate decisions lands below 0.90% (which has happened repeatedly in the post-2008 era, including years of 0.00% fixed rates), buyers who locked in now keep the higher real yield permanently.

This is not speculative. From May 2020 through October 2022, the I-bond fixed rate was 0.00%. Buyers who purchased during that window receive no real yield above CPI, ever. A 0.90% fixed rate today compares favorably to that stretch by a meaningful margin, even if it looks modest in absolute terms.

How Nominal Treasuries Stack Up on Inflation Protection

Nominal Treasury securities do not reset. A 10-year T-note bought today at 4.3% pays 4.3% for ten years regardless of what CPI does. If inflation averages 3.5% over that decade, your real return is roughly 0.8%. If inflation averages 1.5%, your real return is roughly 2.8%. The I-bond adjusts automatically; the Treasury note does not. For investors who believe inflation will remain elevated or unpredictable, that distinction matters. For investors who think the current rate environment is the peak and CPI will drop, a locked-in 10-year Treasury yield looks more attractive than a rate that might reset lower.

Liquidity, Holding Periods, and Early Withdrawal Rules

Liquidity is where I-bonds carry their most tangible cost. You cannot redeem an I-bond for any reason during the first 12 months after purchase. That is a hard rule, not a penalty, the money is simply unavailable. Buy in March 2026, and the earliest you can touch it is March 2027. For emergency funds or cash you might need within the year, this is a disqualifying constraint. For savings with no foreseeable near-term use, the lockup is less consequential.

The Five-Year Threshold and Its Real Cost

Redeeming an I-bond between 12 months and 5 years after purchase triggers a three-month interest penalty. If your bond is earning 4.26% composite and you cash it in at month 18, you forfeit the last three months of interest. On $10,000, that’s roughly $107 in forfeited earnings. Not catastrophic, but worth planning around. Hold for five full years and you keep everything. This structure rewards patient savers and punishes those who underestimate their liquidity needs.

Treasuries work differently. Once issued, they trade on the secondary market, and you can sell whenever you want, though you bear interest rate risk. A 10-year T-note bought at 4.3% will decline in price if yields rise to, say, 5%. Sell early in that environment and you lock in a capital loss. Roll short-term T-bills, and you avoid most of that price risk, but you give up the longer-term rate lock. There is no single Treasury strategy that eliminates all trade-offs.

Laddering Strategies and Time Horizons

Investors with multiple time horizons often use a ladder: short-term T-bills for cash needed in the next 6–12 months, intermediate T-notes for 1–5 year needs, and I-bonds for the “sleep-at-night” portion of savings that won’t be touched for several years. This isn’t a complicated strategy. It is just matching the duration of your investment to the timeline of your actual need. For those already thinking along those lines, the beginner’s guide to investing at MyFinancial101 lays out the full sequencing framework from first savings account to diversified portfolio.

Tax Treatment, Purchase Limits, and the High-Tax-State Advantage

Both I-bonds and Treasury securities share one meaningful tax advantage: interest is exempt from state and local income taxes. For residents of high-tax states, California (up to 13.3%), New York (up to 10.9%), New Jersey (10.75%), this exemption translates to real money. A nominal 4.26% I-bond yield for a California resident in the 9.3% state bracket is effectively equivalent to roughly 4.69% on a taxable instrument. That after-tax edge does not show up in the headline rate comparison but absolutely shows up in your bank account.

Federal Tax and the Education Exclusion

Federal income tax on I-bond interest can be deferred until redemption or maturity (up to 30 years), or you can elect to report it annually. Most holders defer, which provides a modest compounding benefit since you are earning interest on money you would otherwise have paid to the IRS. Treasury bond interest, by contrast, is reportable as ordinary income in the year it is earned. This difference in timing can matter for investors managing taxable income across years, particularly near retirement or during a lower-income transition year.

One underused strategy: I-bond interest used to pay qualified higher education expenses may be fully or partially excluded from federal income tax under IRS rules, subject to income phase-outs. For the 2025 tax year, the exclusion phase-out begins at $96,800 for single filers and $145,200 for joint filers. This effectively makes I-bonds a hybrid savings and education funding tool for households within those income ranges. For those already mapping out college savings options, it connects directly to the broader retirement-versus-college tradeoff discussed in this analysis of prioritizing retirement savings over college funding.

The $10,000 Annual Cap and Ways Around It

The most frequently cited limitation of I-bonds is the $10,000 annual purchase limit per Social Security Number or Employer Identification Number for electronic bonds. TreasuryDirect confirms this cap applies per calendar year with no carryover. A married couple can each purchase $10,000–$20,000 combined. An individual can direct up to $5,000 of a federal tax refund into paper I-bonds, bringing the theoretical annual maximum to $15,000 per person, $25,000 per couple.

Some families also use trust accounts or custodial accounts for minor children to purchase additional bonds, though each entity requires its own TreasuryDirect account and tax identification number. This is a legitimate strategy, not a loophole, but it adds administrative complexity. For investors with $100,000 or more to park, the annual cap means I-bonds can only be one piece of the picture. Treasuries have no purchase limit in any practical sense.

Treasury Bonds vs. I-Bonds: The Real Trade-Offs

The table above tells the structural story. The judgment call depends on three variables specific to you: how long you can leave the money untouched, how large the sum is, and your view on inflation over the next two to five years.

Inflation Scenarios and Their Impact on Each Option

The pattern is clear: the I-bond’s fixed real return of approximately 0.9% is stable across all inflation scenarios. The T-note’s real return swings widely depending on what CPI actually does. That stability is valuable, but only up to the $10,000 cap, and only for holders who can stay in for at least a year.

According to Jeremy Keil, CFP®, CFA, retirement financial advisor at Keil Financial Partners, I-bonds are no longer a “no-brainer” the way they were in 2022, but they remain a straightforward way for part of your savings to beat inflation. The full analysis at Keil Financial Partners covers how to think about the current fixed rate in the context of long-term planning.

The March 2026 Timing Factor Most Buyers Overlook

Buying an I-bond in March 2026 carries a specific timing implication that most headline comparisons ignore. Bonds purchased before May 1, 2026 earn the current rate (approximately 4.03% composite for November 2025–April 2026 issuances) for the first six months, then reset to whatever the May 2026 announcement sets, which we now know is 4.26%. That sequence is favorable: you earn a competitive rate immediately, then step up to a slightly higher one at the reset.

More importantly, any bond purchased before the May announcement locks in the 0.90% fixed rate. The Treasury may lower the fixed rate in May 2026, as it has done in prior cycles when real rates shifted. Investors who bought in March keep 0.90% permanently regardless. This is not guaranteed to happen. But for anyone already planning to buy I-bonds in 2026, acting before May 1 removes the risk that the fixed rate drops.

Keil Financial Partners’ analysis of the current I-bond rate makes the point directly: the reason to buy I-bonds today is to guarantee your cash can beat inflation by 0.9% over the next 30 years. See the full I-bond rate analysis at Keil Financial Partners for the detailed case.

Which Option Fits Your Situation Right Now?

Most safe-money decisions come down to time horizon. Here is a direct framework, not a hedge.

Managing high-interest debt changes the calculation entirely. The after-tax yields discussed here look strong until you compare them against the 20–29% APR on revolving credit card balances, at which point paying down debt first wins by a wide margin. The case for resolving that situation before locking money into any savings bond is made clearly in this guide to prioritizing and negotiating credit card debt.

Your Action Plan

1. Confirm your time horizon before choosing any instrument

   Money you might need in under 12 months should not go into I-bonds under any circumstances. The lockup is non-negotiable. Identify whether your surplus savings is a true long-term reserve or a buffer you might tap. Uncertainty about which it is means keeping it in T-bills or a high-yield savings account until you know.

2. Open a TreasuryDirect account if you plan to buy I-bonds

   Go to TreasuryDirect.gov and create an account using your Social Security Number and a U.S. bank account. The setup process takes about 15 minutes and requires identity verification. Do this before you are ready to buy, accounts occasionally require manual review, and delays can push your purchase past a key rate period cutoff.

3. Buy I-bonds before May 1, 2026 to lock in the 0.90% fixed rate

   The May 2026 rate announcement may or may not lower the fixed component. Buying before that date guarantees the current 0.90% for the life of the bond. For anyone already planning to purchase in 2026, there is no advantage to waiting past May 1. Act before the deadline if the fixed rate matters to your long-term calculation.

4. Max out the annual I-bond cap across eligible buyers in your household

   Each spouse can purchase $10,000 separately, giving a couple $20,000 in annual capacity. A federal tax refund lets you direct up to $5,000 of it to paper I-bonds to increase your annual limit. Consider whether minor children’s custodial accounts or trust entities create additional eligible capacity, but consult a tax professional before setting up new entities solely for this purpose.

5. Allocate amounts above the I-bond cap into Treasuries based on your duration need

   For cash you won’t need for one to two years, 1-year or 2-year Treasury notes offer a known yield with full secondary-market liquidity. For five or more years, weigh longer-duration T-notes against TIPS (Treasury Inflation-Protected Securities), which offer CPI adjustment without purchase limits. Match the maturity to your anticipated need date. Those building skills to supplement income and increase investable savings may find useful context in the rise of micro-freelancing.

6. Calculate your tax-equivalent yield before comparing to other options

   Residents of states with income tax above 5% should multiply the I-bond or Treasury yield by 1 divided by (1 minus their combined federal and state marginal rate) to find the equivalent taxable yield. A 4.26% state-tax-exempt yield in a 9.9% state is equivalent to approximately 4.73% on a fully taxable instrument. Run this math before deciding between Treasuries and bank CDs, money market funds, or other savings products.

7. Revisit the I-bond vs. Treasury allocation annually as rates and inflation reset

   The rate environment in May and November each year will shift the relative attractiveness of I-bonds versus short-duration Treasuries. A future I-bond fixed rate of 0.00% (as occurred before) makes new purchases far less compelling even with CPI protection. Check TreasuryDirect’s rate announcement pages each May and November, and rebalance your safe-money allocation accordingly rather than making a permanent set-and-forget decision.

Frequently Asked Questions

Can I buy I-bonds through my brokerage account?

No. I-bonds are only available directly through TreasuryDirect.gov. They are non-marketable, which means they cannot be bought or sold on any secondary market. Your brokerage account can hold Treasury bills, notes, and bonds, but I-bonds require a separate TreasuryDirect account linked to your bank. This is one friction point that puts some investors off, though the setup process is straightforward once you start it.

What happens to my I-bond rate if inflation drops significantly?

Your composite rate will fall, potentially close to your fixed rate of 0.90%. If the semiannual CPI-U change is zero or negative (deflation), the variable component drops to zero and your composite rate equals your fixed rate. In a scenario of sustained deflation, you would still earn 0.90% annually, the zero floor protects you from a negative composite rate. You would not lose principal, but you would earn less than current T-bill rates if short-duration yields remained elevated.

Is there a penalty for redeeming I-bonds after five years?

No. After the five-year mark, you can redeem I-bonds at any time with no penalty and receive full principal plus all accrued interest. The three-month interest forfeiture applies only to redemptions between 12 months and 5 years. At or beyond 5 years, the exit is clean.

Can I-bonds be held in an IRA or 401(k)?

No. I-bonds cannot be held in any tax-advantaged retirement account, including IRAs, 401(k)s, or HSAs. They are purchased individually through TreasuryDirect and are always held in a taxable account. This actually reduces one of their advantages for people who have substantial IRA space available, since you cannot defer I-bond interest within a Roth or traditional IRA structure. Treasury securities (T-bills, T-notes, T-bonds) can be held in retirement accounts through most brokerages.

How does the I-bond education tax exclusion work in practice?

Redeeming I-bonds in a year when you pay qualified higher education expenses, tuition and fees at eligible institutions, for yourself, a spouse, or a dependent, may let you exclude some or all of the interest from federal income tax. The exclusion phases out at higher incomes (beginning around $96,800 for single filers in 2025). The bonds must have been issued in your name and you must have been at least 24 years old when they were issued. This makes I-bonds a viable supplemental college savings tool, though 529 plans typically offer more flexibility for larger education savings goals.

Are Treasury bills better than I-bonds for an emergency fund?

For a true emergency fund, neither is ideal, but T-bills come far closer. A 4-week or 13-week T-bill can be sold on the secondary market before maturity if absolutely necessary, and you receive the proceeds within a day or two. I-bonds are completely inaccessible for 12 months. Most financial planners recommend keeping emergency funds in high-yield savings accounts or money market funds for instant access, then placing any surplus beyond three to six months of expenses into T-bills or I-bonds depending on the time horizon.

What is the difference between I-bonds and TIPS?

Both adjust for inflation using CPI data, but they work differently. TIPS (Treasury Inflation-Protected Securities) are marketable bonds whose principal adjusts with CPI; they pay a fixed coupon on the inflation-adjusted principal. TIPS can be held in IRAs, bought in any amount, and sold on the secondary market. I-bonds are non-marketable, capped at $10,000 per year, defer taxes until redemption, and have a zero-floor guarantee TIPS do not share. TIPS are better for large portfolios; I-bonds are better for individual savers within the annual limit who want simplicity and tax deferral. The Treasury’s own TIPS vs. I-bond comparison covers the technical differences in detail.

Should I cash out I-bonds purchased in 2022 at the 9.62% rate?

Only if you have a specific use for the cash. Those bonds issued at the 9.62% peak have long since reset to lower composite rates and are now earning somewhere in the 4% range depending on their fixed component. Bonds that passed the five-year mark in 2027 can be cashed out without penalty. Before then, the three-month penalty applies. The real question is what you’d do with the proceeds: if the best available alternative earns a similar rate with more flexibility, the case for cashing out strengthens. Hold if you would simply put the money into something earning less. The fixed component of those 2022 bonds was 0.00% for most of the peak period, which means they offer no real yield floor above CPI, a meaningful disadvantage compared to bonds purchased in 2025 or 2026 with a 0.90% fixed rate.