The new rate for Series I bonds purchased after May 1, 2024 is 4.28%. That includes a new higher base rate of 1.3%, which will stay with the bond for its entire lifetime. Future inflation adjustments to these bonds will be made on top of that 1/3% fixed base rate.

Series I bonds purchased two years ago have NO base rate!  So your old bond (purchased back when rates were over 9%) is yielding only 2.98% for this 6-month period.   That 2.98% is the current inflation adjustment portion of the I-bond.

I bonds purchased between 11/22 and 05/23 carry a base rate of 0.4%, to which you add the current 2.98% adjustment to get your yield.

I-bonds purchased between 05/23 and 11/23 carry a fixed base rate of  0.9%, to which you add the current 2.98% adjustment to get your yield.

Bonds purchased between 11/23 and 05/24 carry a fixed base rate of  1.3%.

Given the huge difference, it might make sense to sell those older bonds that do not have a “base rate” and instead purchase either new Series  bonds — or even Treasury bills.  Taking that action will incur a 3 month’s loss of interest as described below.

Remember,  you must hold I-bonds for at least one year, and will be penalized 3 month’s loss of interest if you cash them in before 5 years.  But with rates having dropped so much, and because they penalize the most recent 3 months interest, this might be a good time to make the switch.