The revolving door btw Wall St. and D.C. is a serious problem. This is a cool idea for an academic study, maybe some sort of event study or diff-in-diff analysis to quantify the cronyist effect. In this case, for example, we'd still have to rule out other causes for the GS jump--start by subtracting off the market return you'd expect given its beta, size, book-to-market-equity, asset growth, momentum, etc. contribution, then see what's left over that can't be explained.