The expected move is the size of the up-or-down change in price that options markets are pricing in for a stock by a given expiration. It is a market-implied estimate read from option prices — not a forecast, and not a range the price must stay inside.

Primary method: the at-the-money straddle

We take the strike closest to the current price that has usable two-sided quotes for both the call and the put, and sum the two mid-prices:

expected move ($) = call mid + put mid (at the ATM strike)
expected move (%) = straddle ÷ underlying price × 100

The intuition: a straddle profits from movement in either direction, so its price is what the market charges for movement itself. The expected range shown on every page is spot − straddle to spot + straddle.

Second method: IV-based

For the constant 30-day figure (EM30) used in rankings we start from interpolated 30-day at-the-money implied volatility (see IV30) and scale it to the horizon:

EM30 (%) = IV30 × √(30 ÷ 365) × 100

The two methods usually agree closely but not exactly — the straddle bakes in the market's actual quotes at one expiration; the IV method standardizes the horizon so different stocks can be ranked fairly. Where a figure appears, its label says which method produced it.

Known limitations

• Straddle mids from wide bid/ask spreads are less precise; illiquid chains can distort the figure.
• Calendar days are used, not trading days.
• Neither method is "correct" — they are two standard readings of the same market prices, and realized moves regularly land outside the range. The historical database exists so you can check how often.