In an NBER working paper, Niels Johannesen, Patrick Langetieg, Daniel Reck, Max Risch, and Joel Slemrod discuss the effects of recent U.S. tax enforcement initiatives on tax compliance. They offer background information about U.S. initiatives since 2009 and conclude, based on administrative microdata, that

[e]nforcement 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.