The U.S. Treasury on May 1, 2026, set the new Series I bond composite rate at 4.26% for all bonds purchased between May 1 and October 31, 2026. That marks a notable jump from the previous cycle and pairs with a 0.90% fixed rate that locks in for the bond’s full 30-year life. A saver who puts $10,000 into I bonds today would earn roughly $426 in the first year, but the real story is what happens after that: the 0.90% floor keeps compounding above inflation for decades, regardless of where interest rates go next.
What the Treasury announced
The official rate notice confirmed three numbers. The composite rate for newly issued I bonds: 4.26%. The fixed-rate component: 0.90%. And the Series EE savings bond rate for the same May-through-October window: 2.40%.
The inflation portion of the I bond formula is built from two snapshots of the Consumer Price Index for All Urban Consumers (CPI-U). Treasury used a September 2025 CPI-U reading of 324.8 as the starting point. The Bureau of Labor Statistics reported a March 2026 CPI-U level of 330.213, completing the six-month measurement window. That works out to a 1.67% semiannual change. Plugged into the statutory formula alongside the 0.90% fixed rate, it produces the 4.26% composite.
Individual purchases remain capped at $10,000 per person per calendar year through TreasuryDirect, with an additional $5,000 available if you direct a federal tax refund toward paper I bonds using IRS Form 8888. Married couples filing jointly can each buy $10,000 electronically, and either spouse can also purchase bonds as gifts to be delivered in a future calendar year without counting against the recipient’s current-year cap.
How this cycle compares to recent resets
Rate resets tell a clearer story when you line them up. In November 2023, the Treasury set the fixed rate at 1.30% and the composite at 5.27%, driven by a steep semiannual inflation reading. By May 2024, the fixed rate held at 1.30% but the composite dipped to 4.28% as inflation moderated. In the cycles that followed through late 2025, both the fixed rate and the composite trended lower as CPI growth cooled.
The May 2026 reset reverses part of that slide. The 4.26% composite is the strongest headline rate buyers have seen in roughly two years. The 0.90% fixed rate, while below the 1.30% offered in late 2023 and early 2024, represents a rebound from the lower fixed rates that prevailed in more recent windows. For anyone who missed the 1.30% fixed-rate cycles, 0.90% is the next best entry point available since then.
Why the fixed rate deserves more attention than the composite
The composite rate resets every six months, so 4.26% is temporary by design. The fixed rate is not. Once an I bond is issued, its fixed component never changes for as long as the bond earns interest, up to 30 years or until the holder redeems it.
That distinction matters over long holding periods. A 0.90% fixed rate means the bond will always pay at least that floor, even during a hypothetical stretch of zero inflation. Every future semiannual reset adds the new inflation reading on top of that 0.90% base. Buyers who locked in bonds during 2022, when the fixed rate was 0.00% despite the eye-catching 9.62% composite, have no built-in real return. Their bonds pay only what inflation delivers. Someone buying at the current 0.90% fixed rate will outperform those 2022-vintage bonds over time, assuming similar inflation trends.
The formula itself is codified under 31 CFR 359.14. In plain terms: the composite rate equals the fixed rate plus twice the semiannual inflation rate, plus a small cross-product of the two. Applied here, that is 0.90% + (2 x 1.67%) + (0.0090 x 2 x 0.0167), which rounds to 4.26%. When inflation runs hot, the inflation component dominates. When inflation is low, the fixed rate does the heavy lifting.
How 4.26% stacks up against other safe-money options
As of late May 2026, top nationally available high-yield savings accounts are advertising rates roughly in the 4.00% to 4.50% APY range, based on data from FDIC.gov and independent rate aggregators. One-year CDs from online banks cluster in a similar band. On the surface, those products look competitive, and they offer daily liquidity that I bonds cannot match.
The difference is durability. A high-yield savings account rate can drop the week after the Federal Reserve cuts its benchmark. The I bond’s 0.90% fixed rate cannot. Over a five-, ten-, or twenty-year horizon, the I bond holder is guaranteed a real return above inflation, while the savings-account holder is exposed to whatever rate environment prevails.
There is also a tax edge. I bond interest is exempt from state and local income taxes, and federal tax is deferred until redemption (or, if used for qualified higher-education expenses, potentially excluded altogether). For savers in high-tax states like California or New York, that deferral and exemption can add meaningful after-tax value compared with a savings account whose interest is taxed annually at both the federal and state level.
For investors comfortable with marketable securities, 5-year Treasury Inflation-Protected Securities (TIPS) offer another comparison point. TIPS real yields have fluctuated in 2026 but have generally traded in a range that makes the I bond’s 0.90% fixed rate competitive for smaller savers, especially given that I bonds carry no market-price risk if held to maturity and no minimum investment beyond $25.
What is still unclear
The Treasury has not publicly explained why it chose 0.90% as the fixed rate for this cycle. The regulation grants the Secretary of the Treasury discretion in setting that component, and no accompanying statement offered reasoning or forward guidance. Whether the 0.90% level reflects an effort to attract retail buyers, a response to broader real-yield conditions, or some internal benchmark is not disclosed.
Purchase volume data following the May 1 announcement has not yet appeared on federal fiscal data portals. Past rate resets, particularly the 9.62% composite in mid-2022, triggered sharp spikes in I bond purchases and overwhelmed the TreasuryDirect website. There is no current public tally showing whether the latest terms are generating similar demand.
Then there is the path of inflation itself. The CPI-U figures baked into the current composite capture price changes only through March 2026. Buyers are making a long-duration bet. If inflation undershoots expectations for years, the 0.90% fixed rate becomes the primary source of real return. If inflation reaccelerates, the composite rate could climb well above 4.26%, rewarding those who locked in the higher fixed component before any future adjustment.
The trade-offs before the October 31 deadline
Buying before the end of October 2026 guarantees exposure to the 0.90% fixed rate for the life of the bond. Waiting until after the November reset means accepting uncertainty about both the inflation component and the fixed rate, which Treasury could raise, lower, or leave unchanged. Because of the $10,000 annual cap, some savers may choose to use their full 2026 allotment now rather than risk a less favorable fixed rate later.
I bonds are not a substitute for an emergency fund. They must be held at least one year, and redeeming within the first five years triggers a penalty equal to the last three months of interest. For anyone who may need immediate access to cash, a high-yield savings account or money market fund remains the better vehicle, even if the rate is less durable.
For those with a multiyear horizon, the calculation is more straightforward. A 0.90% fixed rate layered on top of whatever inflation does next makes this issuance window one of the stronger entry points since late 2023. Bonds must be purchased through TreasuryDirect.gov, and the current rate applies to any bond issued on or before October 31, 2026.
Vince Coyner is a serial entrepreneur with an MBA from Florida State. Business, finance and entrepreneurship have never been far from his mind, from starting a financial education program for middle and high school students twenty years ago to writing about American business titans more recently. Beyond business he writes about politics, culture and history.
