Sen. Ron Wyden (D-Ore.), the chairman of Senate Finance Committee, pledged that his panel would provide vigorous oversight of the IRS as it implements the new stimulus law, starting with an expected hearing featuring Rettig in early April.

Wyden said lawmakers seek a “concrete work plan” from the agency as it embarks on a process to implement vast changes to the tax code that would provide new aid to jobless workers and families with children.