Taking Risk Off Before The Number

Some market moves are unpredictable in timing but not in existence — you don't know if a stock will jump 5% tomorrow, but you know exactly when the jobs report or a central bank rate decision is scheduled, and you know that number has historically moved markets sharply. "The number" is desk shorthand for any scheduled release with a track record of large, hard-to-predict reactions: nonfarm payrolls, CPI, a rate decision, a major earnings report. Trading through one with a full position is a specific, deliberate bet on the outcome; many strategies aren't designed to make that bet and cut exposure instead.

The logic of cutting ahead of a known event

The trade-off is straightforward once you separate the two kinds of risk. A position held through a scheduled event carries a wider range of possible outcomes than the same position held on an ordinary day, because the event can move the underlying sharply in either direction within seconds of release. If a strategy's edge doesn't come from having a specific view on that event, then holding through it isn't earning any extra expected return — it's just adding variance for no compensation. Reducing size ahead of the release gives up a modest amount of exposure to a move that might have gone in the strategy's favor, in exchange for avoiding a move that might have gone badly. For a strategy with no informational edge on the event itself, that trade is favorable on average: you're paying a small, known cost — reduced participation — to remove a large, unknown one.

A worked example

Say a systematic equity strategy normally runs $20 million of exposure to a stock reporting earnings after the close. Historically, the stock has moved 8% or more on earnings day about a third of the time, versus a typical daily move of 1.5%. If the strategy has no specific signal about this earnings report — its edge comes from a slower, unrelated factor — holding the full $20 million through the report means accepting several times the normal day's risk for no additional expected return. Cutting the position to $5 million ahead of the release, then rebuilding it afterward once the price has absorbed the news, keeps the strategy's risk budget roughly consistent from day to day instead of spiking it around a coin-flip.

What this means in practice

Systematic desks often automate this: a calendar of scheduled events feeds directly into position sizing, cutting exposure to affected names by a set amount or percentage a fixed window before release, without a human deciding case by case. The size of the cut is itself a judgment call — cut too little and the event risk isn't meaningfully reduced; cut too much or too early and the strategy gives up real expected return on days when nothing goes wrong, which is most days.