Short Straddle Option Strategy

Selling a call and a put at the same strike and expiration is what this workbook prices out, collecting two premiums in exchange for the obligation to be assigned on whichever side finishes in the money. Losses grow as the underlying moves away from the strike in either direction, and the short call leg has no upper bound, so this is not a defined risk position.

Bid, ask, previous close and the option symbol are fetched on demand for both legs next to the stock's last price, so the credit and both breakevens recalculate as quotes change.