The new rate for Series I bonds purchased after May 1, 2025 is 3.98%. That includes a new base rate of 1.1%, which will stay with the bond for its entire lifetime. Future inflation adjustments to these bonds will be made every 6 months, on top of that 1.1% fixed base rate. The rate will change again on Nov 1, 2025.

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 1.43% for this 6-month period.   That 1.43% is the current inflation adjustment portion of the I-bond.
(For an explanation of this calculation click here: https://treasurydirect.gov/savings-bonds/i-bonds/i-bonds-interest-rates/

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 I-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 before cashing them in. And, you 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.