Short Put Option Strategy

Writing a put obliges you to buy the shares at the strike if assigned, and the premium collected is the whole of the gain. The workbook prices that single leg, showing the credit, the breakeven at strike less premium, and the loss that accumulates as the underlying falls toward zero.

An option symbol is assembled from ticker, expiration and strike, then bid, ask and previous close are pulled on demand alongside the stock's last price. Cash secured or not, the capital standing behind the obligation is what the sheet asks you to size.