Pre-FOMC drift

Pre-FOMC drift is the tendency for broad equity indices to climb in the hours before a scheduled Federal Reserve rate decision, regardless of what the Fed actually announces. It happens before the news breaks. The pattern was first documented in the academic literature studying decades of FOMC meetings, concentrated almost entirely inside that narrow pre-announcement window.

The intuition is simple: a scheduled Fed decision removes a known uncertainty on a known date, and demand for that removal shows up early, bidding index futures higher hours before the announcement itself lands. That is the whole mechanism: positioning ahead of a date already on the calendar, well before any news arrives.

We ran intermarket analysis across everything we tested, looking for genuine cross-asset and cross-event edges. Almost none of it held up. Pre-FOMC drift is the exception: the one directional pattern tied to a scheduled macro event that survived the same real-cost, real-fill scrutiny we apply to everything else in the audit.

We test it the way we test everything else in the audit: real bid/ask, real slippage and financing costs, only the overnight session actually tradable around each scheduled meeting. No next-bar-open assumptions, no cherry-picked windows.

It is also a narrow edge. There are only a handful of scheduled FOMC meetings a year, so it lives in a small set of overnight windows, never something you would trade weekly. The drift itself is small, and the honest question is whether it clears costs at all.

Spread, slippage, and overnight financing on an index position can eat most of it. Few can touch it profitably. Its survival under walk-forward testing is what makes it worth naming: almost every other cross-market and cross-event claim we checked failed outright.

That contrast is the real lesson. Out of every macro-timing and cross-asset claim we ran through the audit, one small, long-documented academic finding held up, and dozens of louder ones collapsed under multiple testing scrutiny. Small and real still beats large and lucky.