The largest implied-volatility moves in the option market, one row per underlying. ATM IV is taken at the contract whose delta sits nearest 0.50, not the strike nearest spot — on a skewed name the strike-picked reading inverts. Rich / cheap divides the expiration’s implied move by the move this stock has typically made over the same horizon across five years of prices; above 1.0 the option market is asking more than history.

Typical move is the median absolute return over the same number of calendar days, measured across five years of adjusted closes — a median rather than a mean, because a handful of crashes drags an average upward and makes every option look cheap. Δ IV z scores the move against this symbol’s own history of daily IV changes, so two points on a 20-vol utility outranks two points on a name that swings that much every day. Price is the latest close. The option columns are priced against the chain’s own spot, read out of it by put-call parity at the money — the loader reaches different symbols at different times, so a row’s quotes may be a session behind its neighbour’s and there is no one date to look the spot up by. Dividing a straddle by the wrong day’s price mis-states the implied move by a whole session’s range. As of is per row on purpose: the chain loader walks its universe oldest-first and does not reach every symbol every night, and a frozen chain still produces a perfectly smooth, entirely fictional IV. Amber means that row is speaking for an older sweep.