What the residual measures
For European options with the same underlying, strike K and expiry, no dividends and frictionless financing, C + K exp(−rT) = P + S. This page reports the signed residual C + K exp(−rT) − P − S and filters its absolute size. Values are per underlying share in the input price units, not per-contract profit.
The calculation uses the provider’s most recent option daily closing prices and a separate underlying quote. They may refer to different times. The rate is an annual continuously compounded assumption. Time is the difference between UTC calendar dates divided by 365; same-day expiry is excluded because this is not an intraday expiry model.
Read coverage before comparing rows
One request returns at most 250 contracts for the selected expiration and strike range. A next-page notice means the chain is incomplete. Only one call and one put at a matching strike, expiry and exercise style, each reporting 100 shares per contract, are analyzed. Missing closes, ambiguous duplicate legs and unsupported multipliers are skipped. A zero close is preserved when explicitly supplied. Confirm deliverables independently: a 100-share field alone does not certify that a contract is unadjusted.
Why a gap is not a trade recommendation
American exercise rights, discrete dividends, stock borrow availability, financing rates and nonmatching observations can break this benchmark. Increasing a threshold does not correct those differences. A real conversion or reversal requires stock and financing legs as well as options; buying one option and selling the other alone does not lock in an arbitrage profit.
Executable analysis needs simultaneous bid/ask quotes, sizes, contract deliverables, fees, margin and borrowing terms. This page does not calculate those cash flows or place orders. An empty table means no eligible returned pair crossed your threshold; it does not establish market efficiency or absence of opportunities elsewhere.
Sources and next checks
Review the Options Industry Council’s parity explanation and Massive snapshot field and pagination documentation. Provider access and quote recency vary. Educational diagnostics are not investment advice.