Does the Expected Move Actually Work? What Happens When You Track the Hit Rate
A bracket with a probability attached
The expected move isn't just a dollar range — it comes with an implicit probability claim. Build it from the ATM straddle (roughly 0.85 times the combined call and put premium) and the market is telling you it expects the stock to land inside that bracket about two-thirds of the time, the same way one standard deviation covers about 68% of outcomes under a normal distribution. That number gets treated as a fact of nature. It's actually a modeling assumption, and it's worth checking how well it holds up against what stocks actually do.
Why the hit rate tends to run above 68%
If you track a stock's actual close-to-close move against its expected move bracket over many periods, the stock lands inside the range more often than the textbook 68% — frequently somewhere in the 75-85% range, depending on the underlying and the time window measured. That's not the market being unusually accurate. It's the same effect covered in the volatility risk premium: implied volatility is priced by option sellers who demand compensation for the risk they're taking on, so IV tends to sit above the volatility the stock ends up realizing. A bracket built from an inflated number is, almost by construction, wide enough to contain the outcome more often than the pure math says it should.
The miss is the part the hit rate hides
A higher-than-68% hit rate sounds like the bracket is conservative in a comforting way, but it hides the shape of the misses. Stock returns have fatter tails than a normal distribution predicts — kurtosis, in the technical term — which means the rare move that does breach the bracket tends to breach it by more than a lognormal model would suggest. Earnings gaps, guidance cuts, and macro shocks don't clip the edge of the range; they frequently blow through it. So the expected move is simultaneously too wide on an average day and too narrow on the day that actually matters. That asymmetry is exactly why a short strangle sold at the edges of the expected move can look profitable trade after trade and then give it all back in one session.
Event brackets behave differently than routine ones
The hit rate isn't one constant number — it splits depending on what's driving the IV that built the bracket. A routine weekly expected move, priced off ordinary trading-day volatility, tends to track closer to the 68% baseline because there's no single catalyst skewing the distribution. An earnings-week bracket is a different animal: IV gets bid up specifically because a binary, gap-risk event is coming, and the post-earnings IV crush means that inflated premium was pricing a real possibility of a large, fast move — not padding. Expected moves built around earnings or FOMC meetings should be read as pricing a genuinely bimodal outcome (quiet reaction or violent one), not a smooth bell curve that happens to be centered on the report date.
What this actually changes about using it
None of this makes the expected move useless — it's still the best single-number summary the option chain gives you for how much room a stock might move. But it's more honest to treat it as a risk range than a forecast: the edges aren't a wall the stock respects 68% of the time on the dot, they're a probability-weighted zone that a premium seller is being paid to accept tail risk around. Sizing a position as if a breach can't happen, because "it's outside the expected move," ignores exactly the scenario that decides whether the trade survives. Widening strikes past the raw bracket, or reducing size relative to the credit collected, is compensation for the fat tail the hit-rate number doesn't show you.
See the current bracket calculated live off the option chain in the expected move overlay, or review the underlying mechanics in the expected move glossary entry.