Series I bonds will pay 4.3% annual interest through October, a drop from 6.89% in November amid falling inflation, the U.S. Department of the Treasury announced on Friday.
There are two parts to I bond interest rates: a fixed rate that stays the same after purchase, and a variable rate, which changes every six months based on inflation.
Starting May 1, the new variable rate is 3.38% and the fixed rate is 0.9%.
While experts predicted the 3.38% variable rate, the fixed rate, which jumped to 0.9% from 0.4% in November, "definitely makes it attractive for long-term investors," said Ken Tumin, founder and editor of DepositAccounts.com.
The 0.9% fixed rate is the highest since November 2007, when I bonds offered 1.2%, Tumin said, noting the new rate was a "pleasant surprise."