I bond rates · May 2023 – October 2023

I Bond Rate for May 2023 – October 2023

Announced May 2023 1 by the Treasury: a fixed rate of 0.90%, a semiannual inflation rate of 1.69%, and the 4.30% composite those two produce.

A bond bought in this period earned 4.30% for its first six months and keeps its 0.90% fixed rate for life. With the current inflation rate of 1.67% it earns 4.26% in May 2026 – October 2026.

The May 2023 – October 2023 composite, worked

Treasury's formula: fixed rate + (2 × semiannual inflation rate) + (fixed rate × semiannual inflation rate), rounded to four decimals.

fixed rate                       0.0090   (0.90%)
semiannual inflation rate        0.0169   (1.69%)
0.0090 + (2 × 0.0169) + (0.0090 × 0.0169)
= 0.0090 + 0.0338 + 0.0001521
= 0.0429521
rounded: 0.0430
composite rate: 4.30%   (Treasury publishes 4.30%)

What this cohort has earned since

Its fixed rate never changes; each later period applies that period's inflation rate to it. Rates take effect on the bond's own six-month anniversaries, not on the announcement date.

Period	Inflation rate	This cohort's fixed	Composite
May 2026 – October 2026	1.67%	0.90%	4.26%
November 2025 – April 2026	1.56%	0.90%	4.03%
May 2025 – October 2025	1.43%	0.90%	3.77%
November 2024 – April 2025	0.95%	0.90%	2.81%
May 2024 – October 2024	1.48%	0.90%	3.87%
November 2023 – April 2024	1.97%	0.90%	4.86%
May 2023 – October 2023	1.69%	0.90%	4.30%

Source: TreasuryDirect — I bonds interest rates (fixed-rate and inflation-rate history). Composites are recomputed with Treasury's formula and checked against Treasury's published figures before publication. Bonds cashed before five years forfeit the last three months of interest.

Informational only, not financial or tax advice.

Last reviewed: May 2026 announcement · snapshot built 2026-10-26 from treasurydirect.gov.

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