The 10–year tax option is a special formula used to figure a separate
tax on the ordinary income part of a lump–sum distribution from a qualified
retirement plan. You pay the tax only once, for the year in which you receive
the distribution, not over the next 10 years. You can elect this treatment
only once for any plan participant, and only if the plan participant was born
before 1936. Form 4972 (PDF) is used to compute
the tax on a lump–sum distribution using the 10–year tax option.
Its instructions contain detailed information. For more information about
lump–sum distributions, refer to Topic 412. Additional material
can be found in Publication 575, Pension and Annuity Income.