The publicly advertised rate for I Bonds according to the Treasury Direct website is 9.62% if they were or are purchased between May and October of 2022.
But what people do not realize is that an I Bond issue month is the same regardless if you purchase it on the first day of the month or the last day of the month. So consider this, if you purchase an I Bond on July 31st of 2022 or in 18 days. Then on August 1st it is already 1 month matured.
So let’s do some basic math. If the current yield is 9.62% then you can divide this by 11. Given that you’re yielding 9.62% in 11 months, not 12. Or technically 11 months and 1 day. This will give you a monthly yield of .8745%. Multiply this by 12 and your annual yield is actually 10.49%