Series I Savings Bonds: Inflation Numbers Released, Time To Buy?
My Money Blog:
Well, the CPI-U that I recently questioned went up 0.9% in March alone. I guess you can’t hide everything.
So, is it time to buy some Series I bonds? First, refer back to this earlier post for a primer as well as some background information. You can ignore the predictions since we have the actual data now.
Calculating the Rates For Next 12 Months
If you buy by the end of April, the fixed rate portion of I-Bonds will be 1.2%. You will be guaranteed an variable interest rate of 3.08% for the next 6 months, for a total interest rate of 4.28%.
After that, the rate will adjust every 6 months based on the previous 6 month’s worth of inflation data. The next adjustment will be in May, based on September-March 2008 data. We can effectively predict this now using the prediction method explained here:
Sept 2007 CPI-U was 208.490. March 2008 CPI-U was 213.528. 213.528/208.490 = 1.02416, or a semi-annual increase of 2.416%.
Total rate = Unknown fixed rate + 2 x Semiannual inflation rate + (Semiannual inflation rate X Fixed rate)
If we assume a fixed rate of the current 1.2%, we get
Total rate = 0.012 + (2 x .02416) + (.012 x .02416)
Total rate = 1.2% + 4.86%
Total rate = 6.06%
Possibly Good Short-Term Investment?
A known “trick” with I-Bonds is that if you buy at the end of the month, you’ll still get all the interest for the entire month as if you bought it in the beginning of…