The same line of thought can be put to CEOs. How do we know a CEO was responsible for a big bump in stock prices? Maybe the marketing team hit gold this year, t

The same line of thought can be put to CEOs. How do we know a CEO was responsible for a big bump in stock prices? Maybe the marketing team hit gold this year, the developers/engineers put out something truly game changing, or the entire market is just on an upswing and the company is doing better in spite of itself.