how is interest accumulated for an I bond?

[Beardog]

Greetings.  I have owned I bonds for years and recently helped my Mom buy some for the first time.  The effective date of the $10,000 purchase was 9/1/2021 and now her Treasury Direct account shows accumulation of $60 over the past 5 months.  The interest rate is 3.54%.  My Mom asked why such little interest has been accumulated and after searching the web in vain for an answer, I come here hoping someone can explain this.  With a rate of 3.54% compounded monthly, I would expect something approaching $150 in interest.  Thanks in advance for any clarity you can bring to this.

[NotJen]

I think it's because of the 3 month penalty if you cash in before 5 years are up.

I have an I-Bond with the purchase date of 10/1/21, and have $28 of interest, which is 3 months at 0% and 1 month at 3.54%.

[Beardog]

I see.  So they add in the three months interest at the five year mark?  I looked at my own account, and I don't see any way to see records of interest being credited to my account.

[reeshau]

I Bonds only compound semiannually.

From TreasuryDirect:

"When are earnings added to the I bond?
I bonds increase in value on the first day of each month, and interest is compounded semiannually based on each I bond's issue date. An I bond's issue date is the month and year in which full payment for the bond is received."