A cluster of empirically documented calendar anomalies tied to the schedule of Federal Open Market Committee (FOMC) meetings. The headline finding — the pre-FOMC announcement drift — is that a large share of the U.S. equity premium has historically accrued in the roughly 24 hours before scheduled FOMC statements, not in reaction to the decision itself. A related result, the FOMC cycle effect, shows that since 1994 the entire equity premium has been earned in "even" weeks of the meeting cycle. The core tension is that both patterns are robust in academic data yet poorly explained by standard risk-based theory, raising uncomfortable questions about information leakage and limiting their practical usefulness as the drift appears to decay over time.

How it's measured / formed

Three distinct but overlapping effects fall under this heading:

• Announcement-day premium (Lucca & Moench, 2015): From September 1994 (when the Fed began announcing decisions) through March 2011, excess S&P 500 returns averaged 49 basis points in the 24 hours before scheduled announcements, cumulating to about 3.9% annually versus ~90 bps on all other days. Returns were >30× larger on announcement days than other days, and they did not reverse afterward. The window is typically measured from the 2:00 p.m. (ET) day-before to just before the 2:15 p.m. release.

• FOMC cycle effect (Cieslak, Morse & Vissing-Jorgensen, 2019): Measuring time in days since the last FOMC meeting, the equity premium since 1994 has been earned entirely in even weeks (0, 2, 4, 6) of the cycle, with negative average excess returns in odd weeks. The difference is statistically significant.

• Meeting-day volatility behavior: The VIX typically declines into and through the announcement as policy uncertainty resolves — a documented part of the mechanism rather than a separate effect.

These are pure calendar effects: they require only the published FOMC schedule (eight meetings/year), not any forecast of the rate decision.

How it's used in practice

The naive implementation is mechanical: go long a broad index (SPY/ES) at the close before a scheduled FOMC announcement and exit near the announcement or at the meeting-day close. Backtests circulated by quant practitioners (e.g., QuantSeeker, 2024) report a long-only SPY version earning roughly 4% CAGR with a ~0.5–0.6 Sharpe ratio over 1993–2024, trading only ~5% of calendar days — figures that should be treated as practitioner estimates, not peer-reviewed, and that depend heavily on cost and slippage assumptions (~5 bps one-way assumed).

More importantly for macro analysts, the effects are used as a conditioning lens rather than a standalone strategy: position de-risking into a meeting, awareness that even-week strength and odd-week weakness color short-horizon tape reads, and recognition that volatility compression around announcements affects options pricing (selling pre-announcement vol that crushes on the print). The cycle effect also informs when during the inter-meeting period drawdowns and rallies cluster.

Adoption, debate & evidence

This is one of the better-documented anomalies in monetary-policy finance, with two Journal of Finance publications behind it, yet it is genuinely contested on three fronts:

1. Decay / regime-dependence. The New York Fed's own follow-up (Liberty Street, 2018) found that after press conferences began at alternating meetings in April 2011, the drift survived only at press-conference meetings (~40 bps day-before-open to lunchtime, plus ~30 bps by end of the conference) and vanished at non-press-conference meetings. Subsequent work (the "disappearing drift" literature, e.g., the 2020 Finance Research Letters study) found that even at press-conference meetings the drift fell from ~44 bps (2011–2015) to ~9 bps (2016–2019), statistically indistinguishable from normal days — attributing the fade to lower average uncertainty (VIX) after the December 2015 ZLB liftoff. The Fed since 2019 holds a press conference after every meeting, which itself erases the press-conference identification that made the post-2011 effect tradeable.

2. No accepted risk explanation. The original authors explicitly called it "puzzling": there is no pre-FOMC drift in Treasuries or money-market futures, and no comparable effect before other major macro releases (CPI, payrolls). A pure risk-premium story struggles because the risk seems concentrated and the compensation is paid before uncertainty resolves. Competing explanations include uncertainty resolution / hedging-demand unwind, investor attention concentrating on Fed communication, and — most provocatively — informal information leakage: Cieslak, Morse & Vissing-Jorgensen tie the cycle effect causally to the Fed and point to systematic informal communication between Fed officials and the media/financial sector as a transmission channel.

3. Conditionality. Both the academic and practitioner literature agree the drift is far stronger when the VIX is high and the yield-curve slope is low; in calm, low-vol regimes the effect is close to zero. This makes it a conditional, not unconditional, phenomenon.

The honest summary: a real, statistically significant historical pattern with a credible (if unsettling) information-leakage component — but one that has measurably weakened in the most recent decade and whose tradeable variant has been partly defined away by changes in Fed communication policy.

Strengths & limitations

When it has worked: in elevated-uncertainty regimes (high VIX, flat/inverted curve), the conditional effect is sizeable and was, for ~1994–2015, one of the most reliable calendar edges in U.S. equities. The cycle effect's even/odd-week split remains a useful descriptive map of when equity-premium risk is compensated.

When it fails / #1 misuse: treating it as a stable, unconditional, year-round edge. The drift is regime-dependent, has decayed post-2016, depends on a fixed eight-meeting schedule, and the press-conference identification that powered the 2011–2018 results no longer exists. Sample sizes are tiny (≈8 events/year), so confidence intervals are wide and a few outlier meetings (crisis cuts, surprise pivots) can dominate a backtest. Leveraged-ETF implementations carry ~18% drawdowns. Any "FOMC drift strategy" pitched with a clean equity curve and no regime conditioning should be treated as overfit until proven otherwise.

Sources

• Lucca, D. & Moench, E. (2015), "The Pre-FOMC Announcement Drift," Journal of Finance 70(1):329–371 — SSRN / NY Fed Staff Report 512
• Liberty Street Economics, "The Puzzling Pre-FOMC Announcement 'Drift'" (2012) — link
• Liberty Street Economics, "The Pre-FOMC Announcement Drift: More Recent Evidence" (2018) — link
• Cieslak, A., Morse, A. & Vissing-Jorgensen, A. (2019), "Stock Returns over the FOMC Cycle," Journal of Finance 74(5):2201–2248 — Wiley
• "The disappearing pre-FOMC announcement drift," Finance Research Letters (2020) — PMC
• QuantSeeker (2024), "Trading the Fed: The Pre-FOMC Drift is Alive" — practitioner backtest, not peer-reviewed — link

Disputes flagged: Whether the drift still exists is actively contested — "alive" (QuantSeeker) vs. "disappeared post-2016" (FRL 2020). The information-leakage explanation (Cieslak et al.) is influential but not settled. Practitioner CAGR/Sharpe figures are unverified by peer review and cost-assumption-sensitive.