Fed Faces Downside Risk from Revised Inflation Data Ahead of Rate Decision

The Federal Reserve is set to make one of its most consequential interest rate decisions of the year, but there's a problem: the inflation data underpinning that decision has an expiration date. The Bureau of Economic Analysis will release its August Personal Consumption Expenditures report on September 30, with methodological revisions expected to retroactively lower core PCE readings by 0.1 to 0.2 percentage points.

Goldman Sachs and JPMorgan have both run the numbers, estimating that May 2026 core PCE could fall from a reported 3.4% year-over-year to somewhere in the 3.2% to 3.3% range after revisions take effect. The revised methodology is designed to more accurately reflect pricing dynamics in areas like cloud computing, streaming services, and healthcare delivery.

Tom di Galoma of Mischler Financial has cautioned against hiking rates on data that's about to be rewritten, pointing to existing internal divisions within the central bank. Some Fed officials have publicly expressed discomfort with tightening further when the labor market shows signs of cooling. Others remain laser-focused on the inflation readings sitting stubbornly above the 2% target and argue that credibility demands action.

The FOMC decision drops September 16, while the revised PCE data arrives two weeks later on September 30. Any rate hike announced on the 16th will be immediately reassessed against new inflation data on the 30th.