A Policy Vote Preceded by a Data Rewrite
The Federal Open Market Committee is scheduled to deliver its interest-rate decision on September 16. Fourteen days later, on September 30, the Bureau of Economic Analysis will roll out a comprehensive revision of the Personal Consumption Expenditures price index — the inflation gauge the Fed has designated as its primary target — stretching back to 2021, and will simultaneously publish the August print within the same release.
The sequencing matters. The inflation reading that hawks on the Committee are leaning on to justify a tightening move is the very figure the government has already scheduled to rewrite. For currency traders watching the dollar, the euro, and the yen, this creates an unusual scenario in which a policy decision will be made on data that is, in the government's own timetable, about to be altered.
FOMC Vice Chair Christopher Waller addressed one of the forthcoming changes publicly on September 3. He noted that a shift in how the Commerce Department treats fees charged to stock-market traders and related financial professionals is expected to shave a few tenths of a percentage point off the 12-month PCE inflation reading. Waller described the adjustment as "a welcome measurement correction," a phrasing that signals the Bureau itself views the prior methodology as flawed rather than merely different.
The political stakes within the Committee are already visible. At the July meeting, three voting members — Beth Hammack, Neel Kashkari, and Lorie Logan — filed a dissent in favor of a quarter-point hike, while the broader group held rates steady by a 9-to-3 margin. Those three dissents crystallize the urgency argument that advocates of an immediate move are pushing into the September session.
The Inflation Trend: Elevated but Decelerating
The core PCE inflation rate currently sits at 3.3 percent, well above the Fed's 2 percent objective. Yet the trajectory tells a more nuanced story than the headline level implies. Using Waller's own figures, the three-month annualized pace of core PCE has declined in a steady sequence, dropping from 4.76 percent in February to 3.05 percent by the July reading. Waller himself acknowledged the level remains above target but characterized the downward movement as "a considerable improvement."
A complementary gauge offers additional context. The Dallas Fed's trimmed-mean PCE measure, which strips out the most extreme price movements in both directions to isolate underlying pressure, has been running at approximately 2.3 percent over the same 12-month window. That figure is not evidence that inflation has already reached the Fed's goal, but it does suggest the underlying trend is less acute than the standard core number conveys.
Part of the gap between the headline core figure and the trimmed-mean reading can be traced to categories where measurement is inherently difficult. Waller has specifically flagged nonmarket services prices — items such as owner-equivalent rent and healthcare that are imputed by statisticians rather than drawn from observable transactions. He has long expressed concern about these components and has argued that setting aside this single factor, the inflation picture is more favorable than the core series suggests.
The BEA Revision and the Legal-Services Problem
The pending BEA overhaul strikes directly at one of the measurement pain points Waller has identified. Legal services, for instance, are currently priced using a consumer index that the Bureau itself has described as producing "erratic changes that cannot be corroborated" against other data sources. The September 30 revision is designed to correct precisely this kind of distortion.
This is not a hypothetical or speculative adjustment. The change has been publicly scheduled, and the historical series will be re-based back to 2021 in the same release that delivers the August number. By the time the FOMC reconvenes on October 28, the Committee will have in hand both the revised historical benchmark and the latest monthly print — a combination it will lack on September 16.
In other words, the hawkish argument for a quarter-point increase will be made, six weeks from now, on a data series that the government has just updated and is prepared to defend publicly. If the revision confirms the tightening case, the argument will be stronger in October than it is today. If it weakens the case, the Committee will have avoided a move that the government's own statisticians subsequently undercut.
What the Sequencing Means for Forex Traders
For participants in the foreign-exchange market, the practical implication is a compressed but meaningful decision window. Two asymmetric risks frame the choice.
If the Fed raises on September 16 and the September 30 revision then lowers the inflation reading, the Committee will have tightened policy on a figure the government subsequently changed. That creates a credibility problem that is difficult to walk back, and it could unsettle the dollar's yield premium in a way that is hard to repair.
If the Fed holds on September 16 and the revision actually reinforces the hawkish case, the Committee retains the option to hike at the October 28 meeting. The cost of waiting is six weeks of slightly looser policy — a manageable gap compared to the reputational damage of acting on data that is then rewritten.
None of this is an argument that current rates are excessive or that the Fed should pivot to easing. It is a narrower point: when the government has already put a date on rewriting the inflation series that underpins the decision, choosing to wait a single meeting is less a sign of indecision and more the analytically defensible course.
For forex desks positioning into the September 16 announcement, the key takeaway is that the data landscape is not static. The September 30 BEA release will effectively reset the baseline on which all subsequent rate expectations are built. Traders who treat the pre-revision PCE as a fixed input into their dollar, euro, or yen models risk anchoring to a number that the government itself has flagged for correction. The 30th comes first. The vote, if it needs to be made, follows.