Separate a current snapshot from historical evidence
A current option-chain snapshot cannot establish what implied volatility was before or after an earlier earnings report. Historical stock returns cannot supply those missing option prices, expirations or model inputs. This page reports current snapshot fields and historical stock-price windows separately; it does not generate substitute historical IV observations.
What the snapshot selection means
The tool requires an upcoming earnings date and a USD-quoted underlying. It requests strikes within 20% of the stock quote, expirations strictly after the earnings date and at most 250 contracts. It finds a matched call and put at the nearest returned strike within the earliest returned expiration with a complete pair. It excludes nonstandard contract sizes. These limits can omit the true nearest strike or expiry; review the contract identifiers and distance displayed.
Call and put IV are displayed as reported annualized ratios converted to percentages. Their mean is shown only when both values are usable. Daily closing premiums are combined only when both positive values have the same reported day-update date. That does not guarantee simultaneous trading or executable prices. The stock quote may be from another moment.
Read the historical price windows
Choose a maximum of 4, 8 or 12 past events. Returned dates are deduplicated and the most recent requested count is used; fewer events may be available. Same-day earnings are treated as pending because announcement timing and a completed daily close may be uncertain.
A before-market report uses the last close before the report date and the first available close on or after it. An after-market report uses the last close on or before the date and the first close after it. When time is unknown, the wider before-date to after-date window is used. The exact start and end dates are always visible. A window is omitted if a required observation lies more than seven calendar days from the event.
For an illustrative close of 100 followed by 104, the price-window change is (104 / 100 − 1) × 100 = 4%. The average shown is the mean of absolute changes across available windows. It is not a forecast, an IV change or a measure of trade profitability. Different windows and missing reports limit comparisons.
What an IV change can and cannot explain
Implied volatility is inferred from option pricing assumptions. Uncertainty around news can affect it, but a decline after earnings is not guaranteed. Option value also depends on the underlying price, strike, remaining time, rates and dividends. A fall in IV does not determine the total gain or loss of an option position.
To study an actual IV shift, record the same contract’s identifier, expiry, strike, IV, underlying price and timestamps before and after an event, then state how you handle time decay and changing moneyness. Those historical option observations are not supplied by this page.
Sources and data limits
- Massive option-chain snapshot fields and pagination
- FMP daily price and company-data endpoints
- OIC explanation of vega and implied volatility
- OIC factors affecting option premiums
Data may be delayed, cached, missing or revised. A quote-date mismatch and a small historical sample are reasons to investigate further, not evidence of an arbitrage or statistical trading edge.