Treasury Raises Series I Bond Rate to 5.51% Amid Rising Inflation

Key points

• Newly purchased Series I bonds will pay a composite annual interest rate of 5.51% from November 1, 2026, to April 30, 2027.
• The new rate is composed of a variable portion of 4.08% and a fixed portion of 1.40%, up from the previous 4.26% composite rate.
• The fixed rate of 1.40% is the highest level recorded since 2006, up from 0.90% in April 2026.
• The variable rate is tied to inflation data, specifically the Consumer Price Index, which rose 3.7% year-over-year in September 2026.
• Existing bond owners will see their variable rates adjust six months after their original purchase date, while their fixed rates remain constant for the life of the bond.
• Investors cannot redeem I bonds for at least one year after purchase, and redeeming within five years results in the loss of the last three months of interest.

Background

Series I bonds have seen fluctuating demand since the post-pandemic inflation peak in 2022, when rates hit a record 9.62%. As inflation cooled, many investors redeemed their bonds. However, recent increases in inflation, partly attributed to energy costs from the Iran war, tariffs, and AI data center demand, have prompted a renewed interest in these government-backed assets. The Treasury adjusts I bond rates every six months, in May and November, based on inflation data and undisclosed fixed-rate calculations.

Why it matters

The rise in I bond rates offers a higher-yield, low-risk option for investors seeking protection against inflation. As consumer price expectations rise, with one-year inflation outlooks reaching 3.9%, these bonds may attract capital from other short-term investments. The increase in the fixed rate component, the highest since 2006, suggests a potential shift in the Treasury's approach to compensating investors for real yields, which could influence broader fixed-income markets.

What to watch

Investors should monitor the next Treasury announcement in May 2027 for further rate adjustments. The variable rate will continue to be tied to inflation data, while the fixed rate may be influenced by real yields from five-year Treasury Inflation-Protected Securities (TIPS). Existing bondholders should track their purchase dates to anticipate when their variable rates will adjust. The overall trend in inflation and consumer price expectations will be key determinants of future I bond attractiveness.