THE LEXICON · THE EXPECTED MOVE
The Expected Move
The expected move is a band either side of spot showing what the options market paid for a day's move, read from the price of the at-the-money straddle on the nearest expiry. It is a price, not a forecast.
Where the number comes from
Take the strike nearest spot on the nearest expiry. Add the price of the call to the price of the put. That sum is the at-the-money straddle, and it is the amount the market is charging for the right to own the day's move in either direction. Set it above spot and below spot and you have the band. Nothing more elaborate happens. The whole construction is one quote, doubled outward from where the index is trading.
The straddle price is a convention rather than a law. Different desks use different conventions. Some interpolate between strikes, some work from implied volatility and scale it to the fraction of a year the expiry covers, some use the mid and some use the last trade. The results sit close together and they are not identical. Any expected move you read anywhere is the output of the convention that produced it, and it moves as the quotes underneath it move.
A price, not a forecast
A forecast costs the forecaster nothing. The straddle costs whoever bought it, and it pays whoever sold it. That is why the number carries information a survey does not. Someone wrote a check for the day's range, and someone else took the other side at that level. The expected move is the size of that bet, marked to the last trade. It is not the options market's opinion about tomorrow. It is the price at which the two sides stopped arguing.
The people on the short side rarely hold the position naked. They hedge it, and the hedging is mechanical: as the index moves, the delta of the straddle changes and the hedge has to be adjusted. That is one reason the band is tied to real obligation rather than sentiment. What that flow does around any given level depends on the gamma regime, which is a separate reading carrying its own assumptions.
What it does not tell you
It says nothing about direction. The band is symmetric by construction, and a symmetric band cannot lean. It says nothing about path either. An index can finish inside the band having spent the middle of the session well outside it, and it can finish outside having never traded far from spot until the last hour.
It is also not a barrier. Nothing enforces the edge. There is no mechanism by which a number derived from a straddle quote holds an index in place, and treating the edge as support or resistance imports a promise the construction never made. Touching the edge is a different event from closing beyond it, and the two are commonly quoted as though they were the same number.
How the desk reads it
The band is a scale, not a signal. It gives the day a unit. When a range-derived level or an objective sits comfortably inside the move the market paid for, it is an ordinary distance; when it sits beyond the band, the level is asking the tape for more than the options market priced. That is the whole use. A level beyond the expected move is a claim that needs a reason of its own.
Penthaus publishes the band in the SPX OPTIONS DESK drawer and in the morning Sheet, next to the other prices of the day rather than above them. It is one input beside skew, term structure and the dealer gamma estimate. Read together, they describe what the options market is currently charging. None of them says what happens next. They say what is being paid right now, which is a smaller claim and a more honest one.
How it gets misread
The common error is turning the edge into a level. Traders fade the upper band or target the lower one as though the number were a wall, when it is only the price of a straddle projected outward. The second error follows: reading the band as a probability the index stays inside, then sizing as though that probability were a fact about the day rather than an output of the same quote that drew the band. The band quoted at the open is not the band at noon.
Where it lives
The band makes more sense read alongside the other prices quoted on the same desk.
THE DESK PUBLISHES THE NQ DEALING RANGE AT 22:03 ET, BEFORE THE SESSION — AND SCORES IT AFTER, EITHER WAY. SEE THE RECORD → · AUDIT THE CHAIN →