Abusive Tax Shelter Shutdown and Taxpayer Accountability Act of 2007

Abusive Tax Shelter Shutdown and Taxpayer Accountability Act of 2007 - Amends the Internal Revenue Code to revise or add provisions relating to tax shelter activity, including provisions to: (1) define "economic substance" for purposes of evaluating tax shelter transactions; (2) increase penalties for large entities and high net-worth individuals for failure to disclose certain tax shelter transactions; (3) impose penalties for understatements of tax due to transactions lacking economic substance; (4) deny material tax advisors a claim of privilege as to the identity of a client; (5) revise standards for the penalty for understatement of tax liability by income tax return preparers and increase the penalties for such understatements; (6) revise and increase the penalties for frivolous tax submissions; (7) deny a tax deduction for interest on underpayments of tax due to nondisclosed reportable transactions and transactions lacking economic substance; (8) expand the authority of the Secretary of the Treasury to disallow certain tax benefits arising from the acquisition of corporate stock; (9) modify certain passive loss rules for controlled foreign corporations; and (10) provide a rule for the reduction in basis of corporate stock for which certain extraordinary dividends are received.