Legislating stock prices

We demonstrate that legislation has a simple, yet previously undetected, impact on stock prices. Exploiting the voting record of legislators whose constituents are the affected industries, we show that the votes of these “interested” legislators capture important information seemingly ignored by the market. A long-short portfolio based on these legislators' views earns abnormal returns of over 90 basis points per month following the passage of legislation. Industries that we classify as beneficiaries of legislation experience significantly more positive earnings surprises and positive analyst revisions in the months following passage of the bill, as well as significantly higher future sales and profitability. We show that the more complex the legislation, the more difficulty the market has in assessing the impact of these bills. Further, the more concentrated the legislator's interest in the industry, the more informative are her votes for future returns.