The U.S. Treasury has set the annual rate on newly purchased Series I bonds at 5.51% for the six months from Nov. 1 through April 30. The rate rises from 4.26% for purchases made through Oct. 31, giving buyers a higher return over the coming rate period.
What changed in the new rate
The 5.51% composite rate combines a 4.08% variable rate tied to inflation with a 1.40% fixed rate. The Treasury adjusts I bond rates every six months, in May and November. The new fixed rate is up from the 0.90% announced in April and is the highest since 2006.
The variable portion reflects the percentage change in the consumer price index over six months. It applies for six months after purchase, then changes according to the next rate announcement. The fixed portion does not change during the life of a bond once purchased.
Inflation has been moving higher: the consumer price index rose 3.7% in September 2026 from a year earlier, compared with 3.4% in August, the Bureau of Labor Statistics reported in October. The I bond’s inflation-linked rate is based on a six-month measure, so the annual inflation figure is context rather than the bond’s variable rate itself.
Who the rate applies to
The new 5.51% rate applies to I bonds bought from Nov. 1 through April 30. Existing bondholders do not all switch to the new rate on the same date. Their rate changes follow a six-month schedule based on each bond’s original purchase date.
For an existing bond, the variable rate updates after its current six-month period ends, while its original fixed rate remains in place. A bond bought with a 0.90% fixed rate keeps that fixed portion even as its inflation-linked portion changes. The return for an owner therefore depends on the bond’s purchase date and fixed rate, not only on the latest composite rate announced for new buyers.
I bonds can earn interest for up to 30 years, but buyers cannot cash them in during the first year. Redeeming before five years means giving up the last three months of interest. Those restrictions matter if you may need the money before the bond’s holding period is complete.
Why buyers are watching inflation
The I bond rate reached 9.62% in May 2022, during the post-pandemic inflation peak, and drew substantial investor interest. Rates later fell as inflation cooled, prompting some short-term investors to redeem their bonds. The new 5.51% rate arrives as inflation has picked up again, though the inflation-linked part will be reset at future Treasury announcements.
In September 2026, consumers’ one-year inflation outlook rose to 3.9%, its highest level in more than three years, in a New York Fed survey released in early October. Higher gasoline and energy costs were among the pressures described for that month, alongside tariffs, demand for travel and investment in artificial-intelligence data centers. Future inflation is not guaranteed, and the variable rate can move when the Treasury resets it.
What remains uncertain
The Treasury does not disclose how it calculates adjustments to the fixed rate, making that part harder to anticipate than the inflation-linked portion. Some experts believe real yields on five-year Treasury Inflation-Protected Securities may influence the decision, but the precise method is not established here.
That uncertainty matters most when comparing a new bond’s fixed portion with the one attached to an existing holding: once set at purchase, the fixed rate stays for the bond’s life. Buyers considering the Nov. 1 rate should check the Treasury’s official announcement for the exact terms and confirm that the one-year lockup and early-redemption penalty fit their plans.
Sources
- Treasury Inflation-Protected Securities — “September inflation sets I Bond variable rate at 4.08%; Social Security COLA will be 3.6%”
- Treasury Inflation-Protected Securities — “The I Bond’s new fixed rate should be 1.40%. However …”
- FedRateCalc — “I Bond Rate November 2026: Fixed Rate Pending”