The Consumer Price Index for All Urban Consumers (CPI-U) increased 0.2% in February on a seasonally adjusted basis, the U.S. Bureau of Labor Statistics reported today. Over the last 12 months, US inflation was flat – 0.0%.

February’s slight increase was expected, because gasoline prices rose 2.4% in the month, after falling 18.7% in January. Overall, the energy index rose 1.0%. Food prices were up a moderate 0.2%. But prices for used cars and trucks were up a sharp 1.0% and medical care commodities rose 0.7%. Apparel was up 0.3%.

‘Core inflation,’ which strips out food and energy, was also up 0.2% in February and has risen 1.7% over the last 12 months.

Holders of Treasury Inflation-Protected Securities and I Bonds are also interested in the non-seasonally adjusted CPI-U, which determines the inflation adjustment to TIPS principal and the future interest rate paid on I Bonds. In February, the inflation index stood at 234.722, up 0.43% over January’s number. But inflation was almost exactly flat over the last 12 months; the February 2014 number stood at 234.781.

Today’s numbers mean holders of TIPS will see gradual increases in principal in April, after several months of deflationary declines. Holders of I Bonds are almost certainly going to see six months of zero interest at the next adjustment on May 1. That adjustment will be based on inflation from September to March 2015, which is currently running at -1.39% with only one month to go. A large negative number will also wipe out any fixed rate the I Bond pays – up to that number – but an I Bond’s principal never declines and its interest rate can never go below zero.

I have updated my Tracking Inflation and I Bonds page to reflect these new numbers. See also my previous posts: TIPS versus I Bonds during deflationary times and Deflation strikes hard in January: What does it mean for TIPS and I Bonds? .

I’d suspect that today’s inflation number will have little effect on the Federal Reserve’s decision to raise short-term interest rates later this year. Oil prices have been declining recently, which should lead to stable gasoline prices as we head into summer.

Here is the 12-month trend in seasonally adjusted CPI-U: