Consumer prices accelerated in August. Gasoline jumped 3.9%. Odds of a Federal Reserve rate hike surged toward 90%. And the S&P 500 closed up 0.9% anyway. That looks like a contradiction until you look at the 1-point gap between headline and core inflation — a gap that explains why markets treated this print as a supply shock rather than a demand problem. Here's the full mechanism, the three ways Wednesday's Fed decision can break, and the specific signals that would prove this read wrong.

Brent crude pushed past $100 a barrel Wednesday for the first time since July 24 — and S&P 500 futures barely moved. That gap isn't complacency. With the 10-year Treasury near 4.80% and futures pricing roughly 60% odds the Fed raises rates next week, the oil shock has already been absorbed through the rates channel instead of the equity channel. Thursday's PPI print is the sharper test of whether it leaks into everything else.

U.S. crude inventories posted their biggest weekly build in 3.5 years — 17.4 million barrels against forecasts calling for a drawdown — and oil still closed higher. The reason is a shipping constraint, not a demand collapse, and it runs straight through energy inflation to a Fed that may be closer to hiking than cutting.