Hello, Suppose you bought 100 shares of stock XYZ for $20.04 You also bought 100 shares of the same stock at $20.30 You write a single in the money call for the strike price $20. At expiration, the stock is at $21. So 100 of your shares get called away. Will GainsKeeper (or similar) say you bought the stock at $20.04, or will it use the $20.30 price? It would be better for you if the software selects the higher $20.30 price. That makes you get more of a loss, so you can tax-offset a greater loss against the premium gain you made. I can live with either one. I just want my own spreadsheet accounting to follow along with what the professional software will do.