To amend the Internal Revenue Code of 1986 to curb tax abuses by disallowing tax benefits claimed to arise from transactions without substantial economic substance, and for other purposes.

Abusive Tax Shelter Shutdown and Taxpayer Accountability Act of 2005 - 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...