Following Federal Reserve Chairman Kevin Warsh's hawkish remarks at the Jackson Hole conference, the market's expectation for a September interest rate hike has substantially increased. Before his speech, the CME Group's FedWatch Tool indicated about a 35% chance of a rate hike at the September 15-16 FOMC meeting. After Warsh's comments, this probability nearly doubled, with traders now pricing in a near 70% chance of a September hike, and federal funds futures suggesting a rate hike of just over 38 basis points for the remainder of the year. This sentiment reflects the market's interpretation of Warsh's stance that the Fed "has work to do" if underlying inflation isn't clearly and sufficiently moving towards its 2% target.

The upcoming August Consumer Price Index (CPI) report, due on September 11, has become the critical determinant for the Fed's September decision. Analysts, including Antje Praefcke at Commerzbank, agree that a robust CPI reading would solidify the case for a rate hike, while a softer-than-expected report could re-open the debate for holding rates steady. This makes the CPI report more decisive than the August employment report, given the Fed's current emphasis on price stability. The release of the CPI during the Fed's "blackout period" — which begins on September 5 and restricts monetary policy commentary — adds another layer of uncertainty for market participants, who may have to interpret the data without immediate official guidance.

While Warsh's speech was widely seen as a significant tilt towards tighter monetary policy, some analysts, like James Clouse, noted that he did not explicitly signal a definite timing for a hike. Nevertheless, economists at Barclays and Societe Generale increased their likelihood of a 25 basis point hike in September, followed by another in December. Stephanie Roth of Wolfe Research also made a strong case for a September hike. The pressure is now on Chairman Warsh to follow through with a rate increase, as failing to do so after such clear signals could potentially undermine his credibility. The decision remains a "coin flip" for some, with a potential rate hike occurring weeks before key congressional elections.