**Elevated energy costs from geopolitical tensions and tariffs are the main drivers lifting September 2026 headline CPI expectations to 3.6–3.7% year-over-year from August’s 3.4%, with market-implied odds clustered tightly around those two prints.** Economist consensus centers on a 0.5–0.6% month-over-month headline gain, reflecting higher gasoline and energy prices amid ongoing Middle East disruptions, while core CPI is forecast to moderate to roughly 0.2% m/m and hold near 2.4% y/y as supercore services ease after August’s spike. Rounding effects, shelter components, and used-vehicle prices introduce outcome uncertainty between 3.6% and 3.7%, consistent with the closely matched probabilities. The October 14 release will also inform the late-October FOMC meeting, where traders weigh whether the data sustains or tempers near-term rate-hike expectations.