The securities advocate wants "transitional relief" for banks and other businesses.
Democratic senators said the findings underscored current problems with the tax code.
The IRS also got fewer visits to its website this filing season.
John Koskinen, the IRS commissioner, has cast this filing season as a success.
Chris Chocola, president of the free market group, calls the extension of the expired tax incentives a "special-interest orgy."
Megan R. Wilson 04/16/14 06:00 AM EDT
House Ways and Means Committee Chairman Dave Camp would be coveted by private sector.
The RNC is seeking documents about the IRS’s improper scrutiny of conservative groups.
Rumsfeld wants tax code reform in his lifetime, adding "there are not many years left.”
House Ways and Means Committee Chairman Dave Camp (R-Mich.) just won't quit trying to change the tax code, despite long odds of change this year.
Americans spend an estimated 2.6 billion hours to file their tax returns each year, and spend $33.6 billion to comply with the tax law, according to a new report.