This paper examines evidence of earnings management pertaining to regulatory-imposed wealth transfers (i.e., political costs) over business cycles. The sample consists of firms subject to merger-related antitrust investigation under Section 7 of the Clayton Act. Industrial organization literature, together with the political cost hypothesis, suggests that these firms' earnings management incentives may vary over national business cycles. Our results indicate that investigated firms do indeed choose income-decreasing discretionary accruals during expansions but not during recessions, in order to reduce the political costs associated with Clayton Act cases. Copyright Blackwell Publishers Ltd 1998.