Weighted average interest rate update; corporate bond indices; 30-year Treasury securities. The weighted average interest rate for December 2005 and the resulting permissible range of interest rates used to calculate current liability and to determine the required contribution are set forth.

Retirement plans; qualification, list of changes. This notice sets forth a list of changes referred to in Rev. Proc. 2005-66 pertaining to the statutory, regulatory, and guidance changes needed for certain requests to the Service.