I think you're doing it wrong

Professor: Brian, Have you ever shorted a stock?

Brian Clegg: Yes

Professor: What do you do?

Brian Clegg: I lose money...

A Sure Thing

Professor:  So you're telling me life in finance is not a sure thing?

Brian Clegg:  It's not.

Professor:  Now do you want to go back and change your major to engineering?

Brian:  No.  I already did that.