This paper examines policies and procedures put in place by corporations to regulate trading in the stock by the firm's own insiders. Over 92% of our sample companies have their own policies restricting trading by insiders, and 78% have explicit blackout periods during which the company prohibits trading by its insiders. Our data indicate that blackout periods successfully suppress trading, both purchases and sales, by insiders, and that the blackout period is associated with a bid–ask spread that's narrower by about two basis points. Consistent with this effect on the spread, allowed insider trades are modestly more profitable than insider trades made during prohibited blackout periods.

A model of major league baseball is developed which distinguishes between league behavior and individual team behavior. The league is viewed as setting rules that restrict the team's willingness to pay and/or impose costs on the transfer of players between teams. Given these rules, teams then compete for player services. The model is estimated and tested. The evidence suggests that the restrictive effect of league rules on player salaries declined between 1986-1988 and 1989-1991, consistent with anecdotal evidence. Within the rules established by the league, however, teams appear to behave as competitive price-takers through the entire sample period.