Data delivery and source status
FNOScan uses NSE and BSE market datasets for its public Indian-market tools. Option-chain, spot, expiry, PCR and participant open-interest data are sourced from NSE datasets; institutional cash activity covers NSE and BSE data. GIFT Nifty data is sourced from NSE IX. Backend APIs are the delivery mechanism and are not identified as the original data source.
The application refreshes option-chain data every 30 seconds, PCR and GIFT Nifty data every 60 seconds, and FII/DII data every five minutes while a page remains open. These are application refresh intervals, not a claim about exchange latency. Every tool displays the timestamp supplied with the latest available dataset.
FII and DII data
Institutional cash-market buy, sell and net values use NSE and BSE data. Participant-wise derivatives open interest uses NSE data. Cash figures are labelled provisional because exchange publications can be corrected after their first release. FNOScan does not combine a missing value with zero and does not treat cash flow as a trading signal.
Put-call ratio
OI PCR equals total put open interest divided by total call open interest for the displayed expiry and row set. Volume PCR and change-in-OI PCR use the corresponding put total divided by the call total. Ratios describe positioning; they are not automatic bullish or bearish signals.
Max Pain and expected move
When the upstream spot response supplies Max Pain, FNOScan displays that value. Otherwise, each displayed strike is tested as a settlement level and call OI × max(settlement − strike, 0) plus put OI × max(strike − settlement, 0) is summed across the chain; the strike with the lowest total is shown. The option-chain expected-move display is 85% of the current ATM call-plus-put premium. Both values change with their inputs and are not forecasts.
Implied volatility and Greeks
Valid upstream IV and Greek values are used when available. When the feed returns zero-filled Greeks, FNOScan uses the Black–Scholes model with spot, strike, option premium, time remaining until 3:30 pm IST on expiry day and a 6% annual risk-free rate. Implied volatility is recovered from the option premium by bounded iteration when the price satisfies Black–Scholes no-arbitrage limits; otherwise a valid end-of-day IV may be used. Delta, Gamma, daily Theta and Vega are model estimates, not exchange-published values. Dividends, futures basis, stale prices and the fixed rate assumption can cause model values to differ from other platforms.
GIFT Nifty implied opening
The displayed gap compares the latest available GIFT Nifty level with its supplied previous-close reference. The implied-opening display uses the same current GIFT Nifty level as an indicative reference. Basis, currency, liquidity, news and movement before 9:15 am IST can cause the actual Nifty opening to differ.
Failures, revisions and missing values
If a client refresh fails, the last successfully displayed values remain on screen with an error message. On a fresh request with no available snapshot, the page shows an unavailable state and retains its explanatory content. Upstream corrections can replace provisional values, and confirmed presentation or calculation errors are handled under the corrections policy.
Licensing and claims
Market data remains subject to the applicable NSE, BSE, NSE IX and FNOScan terms and permitted-use arrangements. FNOScan does not describe a dataset as real-time or exchange-certified unless that status is stated beside the relevant tool. The public display does not grant users a separate right to redistribute the underlying data.