US Congressional investigators will on Thursday accuse UBS and Liechtenstein’s LGT Group of using the “cloak of bank secrecy laws” to help American clients evade billions of dollars in taxes.

A 100-page report to be released by the Senate permanent subcommittee on investigations details allegations about how the banks “colluded” with US clients to help them shield taxable income from regulators even though they knew their clients were seeking to hide from the Internal Revenue Service.