The design is interesting but the test itself is kinda pointless. Fama-French explains about 30% of stock return variation at best so by using stock performance as a measurement you are mostly testing signal (highly credited CEOs) against noise (residual returns).
Another thing is you have to specify your position on EMH here. If you believe the semi-strong form then everything about the CEO should be priced-in immediately after the announcement, which means it will not have a persistent impact on stock return when you slice and dice time periods.
IMO the CEO is just one input out of thousands that influence a stock's performance, which is implied by a lot of asset pricing studies already.
Also managing a public company is an unbelievably complicated job. You have to be one of the "best and the brightest" just to keep the boat bearly afloat sometimes.
Another thing is you have to specify your position on EMH here. If you believe the semi-strong form then everything about the CEO should be priced-in immediately after the announcement, which means it will not have a persistent impact on stock return when you slice and dice time periods.
IMO the CEO is just one input out of thousands that influence a stock's performance, which is implied by a lot of asset pricing studies already.
Also managing a public company is an unbelievably complicated job. You have to be one of the "best and the brightest" just to keep the boat bearly afloat sometimes.