§ 404. Deduction for contributions of an employer to an employees’ trust or annuity plan and compensation under a deferred-payment plan
(a)
General rule If contributions are paid by an employer to or under a stock bonus, pension, profit-sharing, or annuity plan, or if compensation is paid or accrued on account of any employee under a plan deferring the receipt of such compensation, such contributions or compensation shall not be deductible under this chapter; but, if they would otherwise be deductible, they shall be deductible under this section, subject, however, to the following limitations as to the amounts deductible in any year: