Setting it up
Choose the instrument, the expiry and, if you want, a historical date, or turn on live updates. A Refresh contracts button reloads the contract list. Above the chart, ATM Focus shows a cluster of strikes around the money (for example 13 of 55 visible strikes), while Full Chain shows every strike, and a search box finds a specific strike. A header badge shows whether you are looking at a historical snapshot.
The summary cards
| Card | Meaning |
|---|---|
| Underlying and ATM strike | The underlying level and the strike nearest to spot. |
| Average CE and PE | The average call and the average put implied volatility across the visible strikes. |
| Average skew | Put IV minus call IV, averaged across the strikes where both legs traded. |
| Dominant regime | The regime that describes most strikes, with the strike and skew where it peaks. For example Put-side Hedging Premium means puts are richer than calls across most of the range. |
Skew is put IV minus call IV and is shown only when both legs traded. The summary updates when you change between ATM Focus and Full Chain, so compare readings in the same view.
The CE vs PE IV chart
Call IV is drawn as green columns and put IV as red columns at each strike, with the skew as a dotted line against its own axis on the right. A shaded ATM zone marks the strikes nearest spot. In a typical index chart the put columns stand above the call columns and the gap widens toward lower strikes' opposite side, where the calls are far from the money; the exact shape depends on the instrument and the day, so judge a skew against that instrument's normal pattern.
The strike volatility ladder
Below the chart, the ladder lists each strike with its distance from spot, the call's IV, price, volume and open interest, the put's IV, price, volume and open interest, then the PE minus CE skew, the average IV and a bias tag.
| Regime | Rule | What it suggests |
|---|---|---|
| Put Premium | Skew of +1.25 volatility points or more (PE IV above CE IV). | Puts are priced richer than calls at comparable moneyness, often from demand for downside protection. |
| Call Premium | Skew of -1.25 or less (CE IV above PE IV). | Calls are priced richer, which can follow a sharp rally or event positioning. |
| Balanced | Skew between -1.25 and +1.25. | Neither side is bid noticeably harder. |
| Unavailable | One or both legs did not trade. | The IV comes from a stale price, so it is not plotted or counted in the skew and averages. |
Legs that did not trade are shown dimmed in italics, usually deep in-the-money calls with a 0.00% IV. A put premium is common in index options because of structural demand for downside hedges, so judge a skew against the normal shape rather than against zero.
Reading it step by step
- Choose the symbol and expiry, and start in ATM Focus.
- Read the ATM row first as the baseline, then move outward.
- Check whether the put premium is broad across many strikes or confined to a few, using the chart and the ladder together.
- Look at the summary cards: the average skew and dominant regime show whether the picture is of broad put demand, call demand or balance.
- Check events, spot, OI, volume and quote freshness before interpreting a widening gap, and compare nearby expiries during event weeks.
What a gap can and cannot mean
A persistent gap means one side is being bid harder, which often appears around events or after gap openings, and it can show before price reacts. Convergence is common in calm sessions and after the priced event passes. A call-put IV gap alone does not establish directional intent: it may reflect skew, liquidity, model inputs or hedging demand, and implied volatility is model-dependent, so stale prices or wide bid-ask spreads distort it. The implied volatility guide covers each contract's IV level and history, the volatility surface monitor covers the whole surface, and the IV shock simulator covers repricing risk.