What will the next I Bond rate be? Now that we have the 6 month change in the CPI-U for September to March, we know what the inflation-linked rate will be in May 2012. We will now know the fixed rate of the new bonds until the May announcement, but we can calculate what the composite rate may be based on different values for the fixed rate.
The CPI-U increased by 1.1% for this semi-annual period. The fixed rate is currently set at 0%, where it has been for the past 3 consecutive periods. If this fixed rate holds, we can see a May I Bond rate of 2.2%.
| Theoretical Fixed Rate | Composite Rate |
| 0.00% | 2.20% |
| 0.10% | 2.30% |
| 0.20% | 2.40% |
| 0.30% | 2.50% |
| 0.40% | 2.60% |
| 0.50% | 2.71% |
| 0.60% | 2.81% |
| 0.70% | 2.91% |
| 0.80% | 3.01% |
| 0.90% | 3.11% |
| 1.00% | 3.21% |
| 1.10% | 3.31% |
| 1.20% | 3.41% |
| 1.30% | 3.51% |
| 1.40% | 3.61% |
It seems likely the fixed rate will continue to stay at 0%, which would result in a 2.2% I Bond for the first 6 months. Since the current composite rate is 3.06% and it seems unlikely the fixed rate will improve, there is little reason to wait until May to purchase I Bonds.
