Terrorism Insurance Backstop Extension Act of 2005 - Amends the Terrorism Risk Insurance Act of 2002 to define: (1) the term "Program Year 4" as the period from January 1, 2006, through December 31, 2006; and (2) the term "Program Year 5" as the period from January 1, 2007, from December 31, 2007 (thereby extending the terrorism risk insurance program from 2005 through 2007).
Sets a deadline for the Secretary of the Treasury to make a final determination regarding: (1) the availability of group life insurance to both insurers and consumers; and (2) whether certain provisions of the Act shall be applied to providers of group life insurance.
Sunsets the Terrorism Risk Insurance Program after December 31, 2007.
Details the treatment of insured losses and the insurer deductible for the Final Program Year (January 1, 2008, through December 31, 2008).