Historical I bond rates have ranged from a composite low of 0.00% to an all-time high of 9.62% since the program launched in September 1998, with the current composite rate for bonds issued May 2026 through October 2026 set at 4.26%.1TreasuryDirect. I Bonds Interest Rates That enormous range is a feature of the bond’s structure, not a bug. Each I bond pays a composite rate built from two very different pieces, and separating them is the only way to read the history usefully.
The Two Rates Behind Every I Bond
Every I bond carries a fixed rate that stays the same for the bond’s entire 30-year life, plus a semiannual inflation rate that resets every six months based on changes in the Consumer Price Index for All Urban Consumers (CPI-U).1TreasuryDirect. I Bonds Interest Rates The Treasury blends them into the composite rate using a formula in federal regulation: fixed rate + (2 × semiannual inflation rate) + (fixed rate × semiannual inflation rate).2eCFR. 31 CFR 359.13 – Composite Rate
The composite rate can never drop below 0.00%, even when the inflation component turns negative, so a bond never loses principal.2eCFR. 31 CFR 359.13 – Composite Rate With that in mind, the two rate histories tell different stories, and they matter to different people.
Fixed Rate History Since 1998
The fixed rate is the piece that follows your specific bond forever. If you bought when it was high, you’re still earning it today on top of whatever inflation adjustment applies.
From the September 1998 launch through May 2001, fixed rates ran between 3.00% and 3.60%, peaking at 3.60% in May 2000.1TreasuryDirect. I Bonds Interest Rates Rates then drifted into the 1.00% to 2.00% range through roughly 2007 before hitting 0.00% for the first time in May 2008.
From November 2010 through May 2022, the fixed rate sat at 0.00% for most announcement periods, with only occasional upticks to 0.10% through 0.50%.1TreasuryDirect. I Bonds Interest Rates Bonds issued during that long stretch offered inflation protection and nothing more.
The fixed rate began climbing again in November 2022 at 0.40%, rose to 1.30% by May 2024, and has since pulled back to 0.90% for both the November 2025 and May 2026 issues.1TreasuryDirect. I Bonds Interest Rates A few milestone fixed rates worth knowing:
- 3.60% in May 2000, the all-time high.
- 0.00% in May 2008, the first time it hit zero.
- 0.00% for most of November 2010 through May 2022, a near-continuous zero-rate era spanning more than a decade.
- 1.30% in November 2023 and May 2024, the recent peak in the rebound.
- 0.90% for the May 2026 issue.
Inflation Rate History
The semiannual inflation rate is where most of the movement happens, and unlike the fixed rate it applies to every outstanding I bond as it rotates into its next six-month earning cycle.1TreasuryDirect. I Bonds Interest Rates
For most of the program’s history, the semiannual inflation rate has sat between 0.50% and 2.00%. The standout spike came in May 2022 at 4.81%, reflecting six months of rapid consumer price increases. That single reading produced the record 9.62% composite rate that drew national attention to the program.3TreasuryDirect. Series I Savings Bond Interest Rates The November 2022 inflation rate stayed elevated at 3.24% before declining through 2023 and 2024.1TreasuryDirect. I Bonds Interest Rates
The inflation component has gone negative twice. In May 2009, during the financial crisis, it dropped to −2.78%. In May 2015, it fell to −0.80%.1TreasuryDirect. I Bonds Interest Rates The 0.00% floor prevented losses either time. During the May 2009 period, bonds carrying high fixed rates from the early 2000s still earned positive composite rates because their fixed component more than offset the deflation. Bonds with a 0.00% fixed rate simply paid nothing for that six-month cycle.
The most recent inflation rates have stabilized: 0.95% in November 2024, 1.43% in May 2025, and 1.56% in November 2025.1TreasuryDirect. I Bonds Interest Rates
Composite Rate Highs and Lows
The composite rate is what you actually earn, and the swings have been enormous. The all-time high was 9.62% for bonds issued May through October 2022, driven almost entirely by the 4.81% semiannual inflation rate stacked on a 0.00% fixed rate.3TreasuryDirect. Series I Savings Bond Interest Rates That rate applied for only one six-month earning period before inflation cooled and the composite dropped.
At the other end, the composite hit 0.00% during parts of 2015, when the negative inflation component wiped out the already-zero fixed rate on newer bonds.3TreasuryDirect. Series I Savings Bond Interest Rates No principal was lost, but no interest was earned for that stretch either.
Bonds issued in 1999 and 2000 tell a different composite story. Their fixed rates above 3.00% pushed composites above 6.00% even during moderate inflation, and during the 2022 surge a bond purchased in May 2000 with its 3.60% fixed rate earned a composite rate north of 13%. Those same bonds are currently earning composite rates between roughly 6.47% and 6.78% for their November 2025 through April 2026 earning period.1TreasuryDirect. I Bonds Interest Rates
The current composite rate of 4.26% for bonds issued May 2026 through October 2026 reflects the 0.90% fixed rate plus moderate inflation.1TreasuryDirect. I Bonds Interest Rates The November 2025 announcement set the composite at 4.03% for bonds issued during that six-month window.4TreasuryDirect. Fiscal Service Announces New Savings Bonds Rates
What the History Tells You About Buying Now
The single biggest lesson from more than two decades of I bond rates is that the fixed rate does far more work than the headline composite suggests. Someone who bought I bonds in 1999 at a 3.40% fixed rate holds a bond that pays 3.40% above inflation for 30 years. Someone who bought during the viral 9.62% moment in May 2022 locked in a 0.00% fixed rate, meaning their bond now earns only the inflation adjustment with no real return on top.1TreasuryDirect. I Bonds Interest Rates
The 9.62% composite that drew the crowd was a one-cycle event; the 0.00% fixed rate that came with it lasts 30 years. Bondholders from 1999 and 2000 are still collecting on their high fixed rates a quarter-century later.
The current 0.90% fixed rate is modest by late-1990s standards but well above the decade-long zero that preceded it. Whether it rises or falls in future announcements tracks where real yields go across the broader Treasury market. If you’re timing a purchase, watch the fixed rate more than the composite, because that’s the number you’ll live with for the life of the bond.
When New Rates Are Announced
The Treasury announces new fixed and inflation rates on May 1 and November 1 each year.1TreasuryDirect. I Bonds Interest Rates The fixed rate applies to all bonds issued during the following six months. The inflation rate applies to every outstanding I bond as it rotates into its next six-month earning cycle.
The inflation calculation uses a set look-back window. For the November announcement, the Treasury measures the change in CPI-U from March to September; the November 2025 rate was based on the CPI-U rising from 319.799 in March 2025 to 324.8 in September 2025.4TreasuryDirect. Fiscal Service Announces New Savings Bonds Rates For the May announcement, the look-back runs from September to March. Anyone following the monthly CPI releases from the Bureau of Labor Statistics can estimate the coming inflation rate with reasonable accuracy before the Treasury posts it.
One timing detail: I bonds earn interest from the first day of the month you buy them.1TreasuryDirect. I Bonds Interest Rates Interest accrues on the first of each month and compounds semiannually.5eCFR. 31 CFR 359.16 – When Does Interest Accrue on Series I Savings Bonds Buying on April 30 earns the same April interest as buying on April 1, so there’s no benefit to rushing a purchase early in the month. The one date that does matter is the last business day before a rate announcement, since that’s the cutoff for locking in the current fixed rate before it changes.