In popular rhetoric, insider trading cases are about leveling the playing field between elite market participants and ordinary investors. Academic critiques vary. Some depict an untethered insider trading doctrine that enforcers use to expand their power and enhance their discretion. Others see enforcers beset with agency cost problems who bring predominantly simple, easily resolved cases to create the veneer of vigorous enforcement. The debate has, to this point, been based mostly on anecdote and conjecture rather than empirical evidence. This Article addresses that gap by collecting extensive data on 465 individual defendants in civil, criminal, and administrative actions to assess how enforcers operationalize insider trading doctrine. The cases enforcement authorities bring are shaped by a complex and cross-cutting set of institutional and individual incentives, cognitive biases, legal requirements, the history of failed enforcement efforts, and the way in which the agency and the self-regulatory organizations deploy their investigatory resources. SEC enforcement is dominated by small stakes, opportunistic trading by mid-level employees and their friends and family, most often involving M&A transactions. Those cases settle quickly, half within thirty days of filing. Criminal enforcement is generally reserved for more serious cases, measured by, among other things, the type of defendant, the size of the insider trading network, and the profits earned. In both settings, there is little evidence that enforcers are systematically stretching the boundaries of insider trading doctrine.