Revisions Show U.S. Consumer Prices A Bit Firmer Than Previously Reported

U.S. monthly consumer prices rose in December instead of falling as previously estimated and data for the prior two months was also revised up, which some economists said raised the risk of higher inflation readings in the months ahead.

The consumer price index edged up 0.1% in December rather than dipping 0.1% as reported last month, the Labor Department's annual revisions of CPI data showed on Friday. Data for November was also revised higher to show the CPI increasing 0.2% instead of 0.1% as previously estimated. In October, the CPI rose 0.5%, revised up from the previously reported 0.4% increase.

The revisions were the result of recalculated seasonal adjustment factors, the model used by the government to strip out seasonal fluctuations from the data.

This routine procedure, which the Labor of Department's Bureau of Labor Statistics undertakes every year, covered data from January 2018 through December 2022. The not seasonally adjusted data are not revised.

"On the whole, we don't see major implications for our inflation outlook coming from the updated seasonal factors," said Daniel Silver, an economist at JPMorgan in New York. "But the stronger recent trend for the seasonally adjusted data does generate some upside risk looking ahead."

Excluding the volatile food and energy components, the CPI rose 0.4% in December, instead of 0.3% as previously reported. Data for November was revised up to show the so-called core CPI advancing 0.3% instead of 0.2% as initially estimated. October core CPI data was unrevised.

The BLS also updated spending weights used to calculate the CPI, which will be effective with January's CPI report. The weights previously reflected consumer spending in 2019 and 2020.

Housing now accounts for 44.384% of the CPI, up from 43.008%. This reflected an increase in weight for shelter. Transportation now makes up 16.744% of the CPI, down from 17.737%. Food weight dropped to 13.531% from 13.867%.

Data next Tuesday is likely to show the CPI climbing 0.4% month-on-month in January and the core CPI gaining 0.4% as well, according to a Reuters survey of economists.

The survey was, however, conducted before the revisions and updates to the seasonal adjustment factors were published. Some economists, including Morgan Stanley, have since raised their estimates.

Higher inflation led the Federal Reserve to adopt an aggressive monetary policy stance, with the U.S. central bank hiking its policy rate 450 basis points since last March from near zero to a 4.50%-4.75% range. The Fed in recent months has slowed the pace of its interest rate increases.

"Core inflation should move higher again in January as core goods deflation takes a pause and methodological changes boost the housing component," Morgan Stanley said in a note. "Updated index weights could inject additional volatility, but we see the path to disinflation intact beyond January."