"Only an annuity can provide a guaranteed income you can not out live."
NAIC National Association of Insurance Commissioner

Annuities used to fund certain employee pension benefits plans (those under Internal Revenue Code Sections 401(a), 401(k), 403(b), 457 or 414) defer taxes on plan contributions as well as on interest or investment income.  Within the limits set by the law, you can use pretax dollars to make payments to the annuity.  When you take money out, it will be taxed.