The rates are used for calculations such as liabilities, required contributions, and funding targets.
Notice 2010-24 provides guidance as to the corporate bond weighted average interest rate and the permissible range of interest rates specified under § 412(b)(5)(B)(ii)(II) of the Internal Revenue Code.
It also provides guidance on the corporate bond monthly yield curve (and the corresponding spot segment rates), the 24-month average segment rates, and the funding transitional segment rates under § 430(h)(2).
In addition, the notice provides guidance as to the interest rate on 30-year Treasury securities under § 417(e)(3)(A)(ii)(II) as in effect for plan years beginning before 2008, and the minimum present value segment rates under § 417(e)(3)(D) as in effect for plan years beginning after 2007.
Notice 2010-24 is here.