当然，要了解I-bond，功课还要自己做。比如: 至少持有一年才可以兑现；持有不到5年就兑现，要损失3个月的利息。每六个月利息会调整一次
What interest will I get if I buy an I bond now?
The composite rate for I bonds issued from November 2021 through April 2022 is 7.12 percent. This rate applies for the first six months you own the bond.
How do I bonds earn interest?
An I bond earns interest monthly from the first day of the month in the issue date. The interest accrues (is added to the bond) until the bond reaches 30 years or you cash the bond, whichever comes first.
- The interest is compounded semiannually. Every six months from the bond's issue date, interest the bond earned in the six previous months is added to the bond's principal value, creating a new principal value. Interest is then earned on the new principal.
- You can cash the bond after 12 months. However, if you cash the bond before it is five years old, you lose the last three months of interest. Note: If you use TreasuryDirect or the Savings Bond Calculator to find the value of a bond less than five years old, the value displayed reflects the three-month penalty; that is, the amount of the penalty has been subtracted already.
How does Treasury figure the I bond interest rate?
The interest on I bonds is a combination of
- fixed rate
- inflation rate
Fixed rate
You know the fixed rate of interest that you will get for your bond when you buy the bond. The fixed rate never changes.
Treasury announces the fixed rate for I bonds every six months (on the first business day in May and on the first business day in November). The fixed rate then applies to all I bonds issued during the next six months.
The fixed rate is an annual rate.
Inflation rate
The inflation rate can, and usually does, change every six months.
We set the inflation rate every six months (on the first business day of May and on the first business day of November), based on changes in the non-seasonally adjusted Consumer Price Index for all Urban Consumers (CPI-U) for all items, including food and energy.
However, the change is applied to your bond every six months from the bond's issue date. (The dates for these changes might not be May 1 and November 1.) When does my bond change rates?
Combining the two rates
To get the actual rate of interest (sometimes referred to as the composite or earnings rate) we combine the fixed rate and the inflation rate, using the equation in the example below.
- The combined rate will never be less than zero. However, the combined rate can be lower than the fixed rate. If the inflation rate is negative (because we have deflation, not inflation), it can offset some of the fixed rate.
- If the inflation rate is so negative that it would pull the combined rate below zero, we don't let that happen. We stop at zero.
