A look at what happens when sport stars do good and when they do bad

Have you ever wondered what happens to the stock of a sponsoring firm when the endorser does well? How about when the endorser does bad? For example, when Kobe Bryant was arrested, what happened to the firms whose products he endorsed (namely Nike, McDonalds and Coke (the owner of Sprite))? I did and this past year I got talking about it with some students and we could not find much evidence so