U.S. Treasury Sets Series I Bond Rate at 5.51% for Six Months

The U.S. Treasury has set the annual rate on newly purchased Series I bonds at 5.51% for the six-month period from November 1 through April 30, up from 4.26% for purchases through October 31. According to Sina Finance, the composite rate includes an inflation-linked variable component and a 1.40% fixed rate, the highest since 2006; the Treasury said the rounded composite rate is 5.51%. The rate comes as the Consumer Price Index rose 3.7% year over year in September 2026, compared with 3.4% in August. One-year inflation expectations rose to 3.9% in September, their highest level in more than three years, according to a New York Fed survey. For existing bondholders, the variable rate changes according to the six-month schedule after purchase, while the fixed rate remains unchanged. I bonds cannot be redeemed during the first year, and redeeming them within five years means forfeiting the final three months of interest.