Tax Shelter Promoter Liability Act of 2004

Tax Shelter Promoter Liability Act of 2004 - Amends the Internal Revenue Code to increase the penalties for: (1) promoting abusive tax shelters; (2) aiding and abetting the understatement of tax liability; (3) failing to provide required information on potentially abusive tax shelters or for filing false or incomplete information; and (4) failing to maintain a client list of tax shelter investors.

Revises the penalty for failure to report interests in foreign financial accounts to impose a penalty for simple violations (current law imposes a penalty only for willful violations). Allows an exemption from the penalty for reasonable cause, except for willful violations.

Adds a new penalty for failure to include potentially abusive tax shelter information with a tax return or statement. Revises requirements for disclosure of potentially abusive tax shelters and requirements for material advisers with respect to potentially abusive tax shelters to keep client lists.

Disallows tax deductions for the penalties added or increased by this Act.

Extends the limitation period for assessing tax due to underpayments of tax attributable to undisclosed tax shelters.