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Chance of profit, shown as COP in the trading app, estimates the probability that an option position finishes profitable at expiry. Joyride computes COP server-side and exposes it as greeks.pop. The value is a probability from 0.0 to 1.0; the app formats it as a percentage.

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What COP Measures

COP is based on the option’s break-even price, not just whether the option expires in the money. For a long call:
For a long put:
This means COP includes the premium paid for the option. A call can expire in the money and still lose money if the expiry price does not clear strike + option_mark.

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Inputs

The calculation uses: The option mark comes from the order book. A two-sided book uses the bid/ask midpoint. A one-sided book may use the available bid or ask as a degraded but real signal.

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Formula

Joyride uses the same lognormal model family used for Black-Scholes Greeks. First, it evaluates d2 at the break-even price:
Then it converts d2 into a probability with the standard normal cumulative distribution function:
The result is clamped to [0.0, 1.0].

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Long and Short Display

The server value is always the long-side probability. When the app is showing the sell or short side, it displays the complement:

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Missing Values

The app renders -- when there is no trustworthy mark to calculate against. This usually means the book is empty or the quote was rejected as crossed. This is intentional. Using a mark of zero would make break-even equal to the strike and could produce misleading near-100% COP for some in-the-money options.

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Interpretation

COP is a model estimate, not a guarantee. It depends on the current spot price, current book-derived mark, time remaining, and implied volatility assumption at the moment it is calculated. Use COP as one market signal alongside price, liquidity, delta, IV, and your own view of the underlying.