In 2008, the IRS initiated efforts to curb the use of offshore accounts to evade taxes. This paper uses administrative microdata to examine the impact of the enforcement efforts on taxpayers’ reporting of offshore accounts and income. Enforcement caused approximately 60,000 individuals to disclose offshore accounts with a combined value of around $120 billion. Most disclosures happened outside offshore voluntary disclosure programs by individuals who never admitted prior noncompliance. The disclosed accounts were concentrated in countries whose institutions facilitate tax evasion. The enforcement-driven disclosures increased annual reported capital income by $2.5-$4 billion corresponding to $0.7-$1.0 billion in additional tax revenue.