Column (1) is the market yield on U.S. Treasury securities at 30-year constant maturity quoted on investment basis. These were the interest rates used for 415 and 417(e) purposes for plan years beginning prior to 1/1/2008.

Column (2) is the average, determined by the IRS, of the monthly yields for corporate bond indices pursuant to Notice 2004-34. These are used to determine the corporate bond weighted average interest rate and the resulting permissible range of interest rates (Column 7) used to calculate the old current liability values prior to 2008.

Column (3) rates are currently used exclusively for determining IRC 404(o) amounts since 2012. They are the 24-month average corporate bond segment rates without adjustment by the applicable percentage of 25-year average segment rates. Prior to 2012, these rates were also used for IRC 430 minimum funding requirements and IRC 436 AFTAP certifications with an option to use them in 2012.

Column (4) are IRC 430(h)(2)(C) interest rates for minimum funding requirements and IRC 436 AFTAP certifications since 2012. They the 24-month average corporate bond segment rates as adjusted by the applicable percentage of the 25-year average segment rates. There was an option in 2012 to use the old 404(o) rates, but could not use these rates for AFTAP if not used for funding.

Column (5) are IRC 417(e) minimum present value segment rates for lump sum and period certain only annuities since 2008.

Column (6) rates are used to value vested benefit for PBGC variable premiums since 2008. Note that for plan years beginning in 2012 and later, they are the same as the IRC 417(e) minimum present value segment rates (Column 5)

Column (7) shows the range of interest rates, which are still published by the IRS, for the old Current Liability amounts for funding purposes prior to 2008.

Column (8) rates were used to calculate interest charges for late or missed quarterly contribution requirements prior to 2008.

Column (9) are the interest rates used for accumulating employee contributions in Defined Benefit plans.