1. John owns shares of Company A. He considers selling his shares and buying stock in Company B, but decides against it. He now finds he would have been better off by $20,000 if he had switched to Company B. Mary owns shares in Company B, but switched to Company A. She finds she would have been better off by $20,000 if she had kept her shares of Company B.

Discuss the role of regret in the disposition effect based on this example.