Two partners from Skadden, Arps, Slate, Meagher & Flom are among the lawyers whose clients are scheduled to appear Thursday before a Senate subcommittee investigating whether and how some of America’s wealthiest citizens hide billions of taxable income in illegal shelters abroad.

The hearing stems from a U.S. Department of Justice investigation of Swiss banking giant UBS and a royal bank in Liechtenstein that allegedly have helped U.S. citizens hide taxable income for years. As part of its investigation, the government is seeking the names of thousands of U.S. citizens who may have cheated the IRS.