Tom Adams: New I Bond Inflation Component will be 3.10%
Tom Adams has calculated that, come the semi-annual savings bond rate adjustment November 1, the inflation component of the I Bond yield will be 3.1%, so judging what Treasury decides to do with the fixed component of the yield, new I Bonds will likely yield between 4.1% and 4.5% (that last part is me talking). Older I Bonds will yield anywhere between 4.1% and around 6.7%, depending on what the fixed yield component was when they were purchased.
Says Adams:
The Consumer Price Index fell during September to 202.9 from August's 203.9. The Series I Savings Bond inflation component is based on the level of the CPI in March and September. In March the index was at 199.8. This means the next I bond inflation component will be 3.10%.
To determine what your own I bonds will earn during their next six-month rate period, you have to add their fixed base-rate to 3.10%. The fixed-base rate for your I bonds can be anywhere between 1.0% and 3.6%, depending on when the I bond was issued.
Meanwhile, older variable rate EE savings bonds (those issued between May 1997 and April 2005) seem on track to earn about 4.4% come the November readjustment, given the recent relatively high yields on the 5 Year Treasury (these older EE savings bonds are pegged to 90% of the fiver's average yield for the six months preceding the readjustment).
Where Treasury will set the rate for new fixed-rate EE bonds is anybody's guess.