The Pre-FOMC Drift: An Anomaly in US Equities

A Documented Market Oddity from the New York Fed

If someone told you that roughly 80% of the annual equity risk premium in the US has historically been earned within a handful of trading days, you might assume they were exaggerating. Yet a 2011 staff report by New York Fed researchers Davide O. Lucca and Emanuel Moench documented exactly this: in the 24 hours before scheduled FOMC announcements, the S&P 500 has delivered abnormal returns far in excess of ordinary trading days. On the announcement day itself, returns net out close to flat—a pattern that runs directly counter to the textbook prediction that risk premia should be realized at the moment new information arrives.

The phenomenon is not isolated to the US. Lucca and Moench observed similar pre-meeting drifts in Germany, the UK, Switzerland, Japan, and other developed markets. Notably, no comparable drift exists in the US Treasury market, which directly challenges the standard financial-economics argument that excess returns must compensate for some form of risk.

How Big Is the Drift?

The original research found that the average 24-hour pre-FOMC abnormal return was about 49 basis points—more than thirty times the average daily return on non-meeting days. In other words, a long-only equity portfolio has historically accumulated the bulk of its annual alpha within roughly 8 meeting days × 24 hours each year.

A 2018 update from Liberty Street Economics extended the sample through June 2018. The conclusion: the drift still exists, but since Bernanke introduced regular post-meeting press conferences in April 2011, the effect has become increasingly concentrated in those press-conference meetings. As the Fed's communication regime evolved, the market's attention structure evolved with it.

Three Explanations

First, attention concentration. Both rational and irrational attention models predict that investors think hardest about policy when an event is imminent, and that this concentrated repricing—reweighting both cash flows and discount rates—is itself what pushes prices up.

Second, information leakage. Lucca and Moench tested this directly: the sign of pre-announcement returns shows no significant correlation with the sign of returns on the announcement day. If someone knew the result in advance, that correlation should be strong. It is not. The pre-meeting window also falls inside the Fed's official blackout period, so no public signaling by policymakers should be occurring.

Third, complexity. Monetary policy affects equity prices through both a cash-flow channel and a discount-rate channel. Pricing both correctly is harder than pricing an ordinary earnings release, so the market gradually incorporates the news in the hours before the official announcement.

After 2015, the Drift Quietly Disappeared

The most important follow-up is Alexey Kurov and co-authors' 2021 paper, "The Disappearing Pre-FOMC Announcement Drift." Using data from 1994 through 2018, they found:

The drift first emerged in meetings that featured Chair press conferences, and then essentially vanished after 2015. Once the anomaly became widely known and was traded by quant funds, its alpha disappeared.

For systematic traders, this is a textbook anomaly-decay story: as soon as an effect becomes consensus, the arbitrage capital flattens it. Kurov and co-authors also note that the Fed's 2014 intensification of forward guidance and press-conference structure pushed transparency to a new level, which simultaneously squeezed the room for pre-positioning.

Conditional Drift: When Does It Still Show Up?

The unconditional average may be gone, but conditional drift is still detectable. Pre-FOMC returns are stronger when:

The VIX is elevated (market fear is high). The Treasury yield curve is flat (recession worries intensify). The more uncertain the policy outcome, the greater the friction of repricing—and the more visible the pre-meeting drift becomes.

This also explains why, during the 2024–2026 period, when the VIX repeatedly poked above 20, indices like SPX and QQQ frequently rallied into the FOMC blackout window. The drift's existence does not, however, mean the announcement itself is predictable.

How to Actually Use This

First, pure event arbitrage—buying into the meeting and exiting on the announcement—has not been a reliable alpha source since 2015. Anyone still backtesting the strategy should expect sharply compressed hit rates and Sharpe ratios.

Second, the real lesson is the existence of event-driven volatility. The pre-meeting buying is essentially the market paying to resolve uncertainty early. For short-term traders, VIX options, short puts, and event-vol-selling structures still tend to find attractive risk-reward inside this window.

Third, macro traders should track conditional drift. When the VIX is persistently elevated, the curve is flat, and the Fed faces a highly uncertain policy decision, the pre-meeting bid tends to be visible. Crucially, a visible bid is not a guaranteed direction—only a directional risk-reward that tilts slightly positive. The actual announcement outcome remains a random variable.

Why This Anomaly Is Worth Remembering

The pre-FOMC drift is a textbook case of a complete anomaly lifecycle: discovered, explained, arbitraged, and ultimately decayed. It teaches three things.

First, markets are not always efficient, but they become more efficient as participants learn. Second, anomalies do not vanish completely; they tend to reappear in conditional forms—during high-VIX or high-uncertainty regimes. Third, real alpha comes not from memorizing which anomalies work, but from understanding the underlying microstructure and information architecture.

Next time you see the index grind higher into an FOMC meeting and your feed fills with headlines about a "pre-FOMC rally," pause and remember: you are watching a thirty-year-old story that was documented in 1994 and arbitraged into oblivion after 2015.