Given the new CPI-U linked rate of .77%, we can now determine the composite rate for currently issued I-Bonds. An I-Bond purchased before May 1 will have a fixed rate of 0.30% and will earn the current composite rate of 3.36% until October 1, when it will switch to 1.84%.
| Fixed Rate | Composite Rate |
| 0.00% | 1.54% |
| 0.10% | 1.64% |
| 0.30% | 1.84% |
| 0.70% | 2.25% |
| 1.00% | 2.55% |
| 1.10% | 2.65% |
| 1.20% | 2.75% |
| 1.30% | 2.85% |
| 1.40% | 2.95% |
| 1.60% | 3.15% |
| 2.00% | 3.56% |
| 3.00% | 4.56% |
| 3.30% | 4.87% |
| 3.40% | 4.97% |
| 3.60% | 5.17% |
The March CPI-U value increased to 217.631 and completes the range used to calculate the next variable rate, which goes into effect on May 1st.
Given the increase from September’s value of 215.969 to March’s value of 217.631, the CPI-U value increased by .76955%, which will be rounded to .77%.
| Sep. | Oct. | Nov. | Dec. | Jan. | Feb | Mar. |
| 215.969 | 216.177 | 216.330 | 215.949 | 216.687 | 216.741 | 217.631 |
All bonds sold May 1 through October 31 will have a CPI-U linked rate of .77% and an as yet unknown fixed rate. Currently issued I-Bonds will switch to the new rate on the 6-month anniversary of the issue date.
The CPI-U value for February increased slightly to 216.741. The CPI-U value has hovered around 216 for each of the periods so far with only one month left before the next variable rate will be known.
| Sep. | Oct. | Nov. | Dec. | Jan. | Feb | Mar. |
| 215.969 | 216.177 | 216.330 | 215.949 | 216.687 | 216.741 |
The January 2010 CPI-U value increased to 216.687, up from December's fall to 215.949.
There are 2 months remaining for determining the next variable rate portion of an I bond's composite rate.
CPI-U for the May I Bond rate:
| Sep. | Oct. | Nov. | Dec. | Jan. | Feb | Mar. |
| 215.969 | 216.177 | 216.330 | 215.949 | 216.687 |
I-Bonds and CPI-U values
The December CPI-U value dropped slightly to 215.949.
CPI-U for the May I Bond rate:
| Sep. | Oct. | Nov. | Dec. | Jan. | Feb | Mar. |
| 215.969 | 216.177 | 216.330 | 215.949 |
The CPI-U for November rose slightly to 216.330 from October's value of 216.177.
| Sep. | Oct. | Nov. | Dec. | Jan. | Feb | Mar. |
| 215.969 | 216.177 | 216.330 |
The CPI-U value for October rose to 216.177 from September's value of 215.969.
The May 2010 I-bond will use the difference in CPI-U values between September and March to determine the inflation-linked rate.
| Sep. | Oct. | Nov. | Dec. | Jan. | Feb | Mar. |
| 215.969 | 216.177 |
