The authors examine the antitrust implications of certain market behavior, using recent findings from research on competitive market signaling. They show that certain behavior of a firm that is sometimes thought to raise antitrust concerns should be viewed as a natural and permissible facet of competitive interplay in the market. Conversely, they identify other market behavior that should be viewed with much more caution due to the antitrust risks of such behavior. The authors offer new perspectives on the motives and intentions that drive market behavior but may or may not raise antitrust concerns. They also show how competitive signaling research holds considerable promise for a better understanding of when serious antitrust issues are or are not triggered by particular market actions.