Option Implied Volatility Chart
An option contract's Implied Vol Charts tab plots the strike's mid implied volatility, from the call's and put's bid and ask, through today's session against the previous close, with the day's largest trades as dots. Its Historical view shows the IV at each day's close, with the call and put volume.
What is the implied volatility chart for one option?
An option contract's page on Market Chameleon has an Implied Vol Charts tab. It plots the option's implied volatility (IV): the volatility its price implies, in annualized percentage points. It has two views. Current follows the IV through today's session against the previous close, with the day's larger trades marked where they printed. Historical shows the IV at the end of each trading day, with that day's call and put volume.
An option's price moves with the stock, so a price chart mixes two things. The IV chart largely takes the stock's move out and shows whether the option got more or less expensive in volatility terms.
How the IV line is computed
- Bid IV and ask IV. Through the day we take snapshots of the option's quote and turn its bid and ask prices into implied volatilities.
- One line for the strike. Put-call parity ties a call and a put with the same strike and expiration to roughly the same implied volatility, so the chart uses both. It takes the higher of their two bid IVs and the lower of their two ask IVs - the tightest volatility market across the call and the put - and plots the midpoint. The call and the put at a strike therefore show the same line.
- Previous Close is the same midpoint from the previous trading day's last snapshot, drawn as a flat dashed red line from the open to the close.
- Call Trades and Put Trades. Dots for the day's 200 largest trades in the call and the 200 largest in the put, by contracts, each placed at the implied volatility of its trade price. Hover over a dot to see the trade, for example "500 @ 2.15 IV: 31.4": contracts, price and IV.
- Historical applies the same midpoint to the last snapshot of each trading day, from the first day we have quotes for the contract up to today. Bars on the right-hand axis show that day's volume in the call and in the put at the strike.
Implied volatility, not a forecast: it is what option prices imply about future moves, and it changes as prices do.
Reading the chart: an example
The Current view for a short-dated option on an earlier trading day, captured around 1:00 PM.
- Solid line - the strike's mid IV. Here it opened near 13 to 14, dipped toward 12 in the first half hour, then climbed to about 18.5 by 1:00 PM.
- Dashed red line - the previous close, about 17. The IV crossed above it after 12:30, so by then the option was more expensive in volatility terms than at the previous close.
- Orange dots - put trades. Early in the day they cluster tightly around the line: they traded close to the midpoint.
- Blue dots - call trades, scattered more widely. A dot above the line traded above the midpoint, toward the ask; a dot below it traded toward the bid.
Drag across the Current chart to zoom into part of the day; right-click to reset. In Historical, drag the handles of the small chart underneath to pick the dates.
What you can find out
How can I see the implied volatility history of one option?
Open the contract's page, choose Implied Vol Charts, then Historical: one point per trading day, from the first day we have quotes for the contract to today, with that day's call and put volume as bars. For the numbers day by day - VWAV, the high and low trade IV and the closing midpoint IV for the last 90 trading days - use the Historical Data tab. Read about the Historical Data tab
How does an option's IV change during the day?
The Current view plots it snapshot by snapshot from the open. Implied volatility tends to rise when the stock moves sharply or news is pending, and to fall once an event such as earnings has passed; near expiration it can swing widely. Compare the line with the dashed previous close to see where today stands. See the example
Did today's big trades print above or below the market's IV?
Each dot is a trade at its own implied volatility. Dots above the line traded above the midpoint, often a buyer paying up; dots below traded toward the bid. Large trades above the line followed by a rising line point to buying pressure in the option. For each trade with the bid and ask at that moment, use Time And Sales. Read about time and sales
Is the option's IV higher or lower than at the previous close?
Compare the line's latest point with the dashed red line. The Summary tab gives the same comparison in numbers: Bid IV and Ask IV next to Prev. Bid IV and Prev. Ask IV, and the percent change in the mid IV. Read about the Summary tab
How does this option's IV compare with the stock's overall IV?
The contract chart covers one strike and expiration. For the stock's 30-day implied volatility (IV30), open its IV chart, for example SPY's IV chart. Strikes of the same expiration usually trade at different implied volatilities: that pattern is the skew. Read about volatility skew
Where to find it
- 1Open the stock's option chain, for example /Overview/AAPL/OptionChain/, and pick an expiration.
- 2Set View to Stacked and click a contract symbol: its page opens in a new tab.
- 3Choose Implied Vol Charts, then Current or Historical above the chart.
The address is /options/quote/<contract symbol>/implied-volatility-charts, where the symbol is the standard OCC code, such as AAPL261218C00250000 for the AAPL 250 call expiring December 18, 2026. More about option contract pages
Contract pages are for Premium and Premium Options members; everyone else sees a short page with the free-trial offer.
FAQ
- Why do the call and the put at the same strike show the same IV line?
- The line combines both: the higher of their bid IVs and the lower of their ask IVs, averaged. Put-call parity keeps a call and a put with the same strike and expiration at roughly the same implied volatility, so combining them gives the tightest market.
- How far back does the Historical view go?
- To the first day we have quotes for the contract, one point per trading day up to today. A recently listed contract has a short history.
- Why are only some trades shown as dots?
- The chart plots the 200 largest trades of the day in the call and the 200 largest in the put. Time And Sales lists each trade.
- What does an IV of 30 mean?
- The option is priced as if the stock's annualized volatility were 30%: roughly a one-standard-deviation move of 30% over a year, or about 8.7% (30% divided by the square root of 12) over a month.
- Who can see the IV chart?
- Premium and Premium Options members, like the rest of the option contract page.
Related
Option contract summary page Option contract historical data Implied and historical volatility Option volatility skewTerms on this page
Implied volatility Put-call parity Volatility skew IV30 Bid-ask spreadMarket Chameleon provides data, not investment advice.