US Core CPI Up 0.3% in August as "Supercore" Services Reaccelerate

August's CPI report challenged the view that inflation is steadily cooling. Core CPI rose 0.3% month over month, above the 0.2% consensus forecast, with "supercore" services once again leading the upside surprise. Supercore services—a services measure that excludes both energy and shelter—increased 0.5% in August, more than double July's 0.2%. The pickup comes as policymakers head into the Fed's Sept. 15–16 meeting, where officials have been monitoring this category closely. Why the Fed watches supercore The Fed treats supercore as a window into labor-driven inflation. Labor-intensive services such as medical care, air travel, and restaurants tend to track wage growth more directly than goods prices. A 0.5% monthly increase signals that underlying wage pressures may still be too firm for inflation to return to the Fed's 2% target on a sustained basis. Headline CPI rose 0.4% month over month and 3.4% year over year, in line with expectations. Beneath the surface, goods inflation has eased and shelter is beginning to show early signs of cooling, but supercore strength continues to keep core inflation elevated. Markets price in a higher chance of a September hike Ahead of the August CPI release, market-implied odds of a rate increase at the September meeting were around 70%. After the data, pricing shifted quickly to roughly 90%. Fed Chair Kevin Warsh has indicated a willingness to tighten further if inflation remains high, and the latest numbers leave less room to argue for patience. The report followed a stronger-than-expected Producer Price Index and came alongside rising oil prices, adding to a cluster of inflation signals. Supercore inflation has remained above pre-pandemic norms through much of 2026, and the San Francisco Fed has pointed to the category as one reason overall inflation has been difficult to bring down. If a 0.5% monthly pace in supercore services were to persist, it would translate into roughly 6% annualized inflation—about triple the Fed's target. What to watch next Investors will be focused on key services components that have consistently supported supercore readings: airfares, medical care, and food services. Airfares are often volatile, so a single-month surge does not necessarily establish a trend. Medical care inflation typically proves more persistent, reflecting insurance-pricing cycles and hospital pricing that adjusts more slowly.