Identifying contracts,combinations and conspiracies in restraint of trade

Antitrust guidelines rely on structural screens to review horizontal merger proposals for possible anti-competitive effects. This paper extends this screening approach to forecast where industry cartels will form, and where cartel agreements are more likely to raise price. I test the screen's reliability for a unique data set of legal, privately enforced industry cartels that formed under the Webb-Pomerene Export Trade Act. Consistent with screening assumptions, I find that cartels formed more frequently in industries with significant potential market power, high barriers to entry, and conditions facilitating the enforcement of agreements. However, these characteristics generally perform less well at distinguishing when cartels are likely to raise price without generating offsetting cost-savings, suggesting that screening is reliable only as a preliminary check for possible anti-competitive behavior.