IV methodology & coverage
For the selected expiry, choose the standard 100-share strike closest to the stock price with both a Call and Put. Rank by their mean IV. Ties choose the lower strike. No substitution when ATM IV is missing.
Active US-listed common stocks and common ADRs only; funds, preferred shares, indexes and adjusted deliverables are excluded. Stocks without a standard pair for this expiry do not enter the ranking. IV is annualized and is not a forecast of the stock’s return. Quote times describe quote evidence; observed time describes snapshot collection. IV calculation time is not supplied. OI is the provider’s prior-session figure; volume is the selected pair’s session volume.
The default is the nearest Friday; after its regular-session close, it rolls to next Friday. Choose Monday, Wednesday or Friday in the calendar. Holiday-shifted Thursday expirations are not mixed in. During the refresh window, evidence is cached for 15 minutes. After-close snapshots are reused until the next trading session. Collection time is not IV calculation time; an after-close snapshot is not verified settlement IV. No historical snapshots are kept. IV evidence is delayed by 15 minutes and includes no bid/ask quotes. The stock and contract directories are reused for one day; company references for seven days. Market cap is the provider’s company-reference value, not an intraday calculation. A cap filter excludes stocks with unknown market cap.
