(b) In order to be deductible under
section 404(a), contributions must be expenses which would be deductible under
section 162 (relating to trade or business expenses) or 212 (relating to expenses for production of income) if it were not for the provision in
section 404(a) that they are deductible, if at all, only under
section 404(a). Contributions may therefore be deducted under
section 404(a) only to the extent that they are ordinary and necessary expenses during the taxable year in carrying on the trade or business or for the production of income and are compensation for personal services actually rendered. In no case is a deduction allowable under
section 404(a) for the amount of any contribution for the benefit of an employee in excess of the amount which, together with other deductions allowed for compensation for such employee's services, constitutes a reasonable allowance for compensation for the services actually rendered. What constitutes a reasonable allowance depends upon the facts in the particular case. Among the elements to be considered in determining this are the personal services actually rendered in prior years as well as the current year and all compensation and contributions paid to or for such employee in prior years as well as in the current year. Thus, a contribution which is in the nature of additional compensation for services performed in prior years may be deductible, even if the total of such contributions and other compensation for the current year would be in excess of reasonable compensation for services performed in the current year, provided that such total plus all compensation and contributions paid to or for such employee in prior years represents a reasonable allowance for all services rendered by the employee by the end of the current year. A contribution under a plan which is primarily for the benefit of shareholders of the employer is not deductible. Such a contribution may constitute a dividend within the meaning of
section 316. See also
§§ 1.162-6 and 1.162-8. In addition to the limitations referred to above, deductions under
section 404(a) are also subject to further conditions and limitations particularly provided therein.