Paragraph not to apply in certain cases

This paragraph shall not have the effect of reducing the amount otherwise deductible under paragraphs (1), (2), and (3), if no employee is a beneficiary under more than 1 trust or under a trust and an annuity plan.

If, in connection with 1 or more defined contribution plans and 1 or more defined benefit plans, no amounts (other than elective deferrals (as defined in section 402(g)(3))) are contributed to any of the defined contribution plans for the taxable year, then subparagraph (A) shall not apply with respect to any of such defined contribution plans and defined benefit plans.

In the case of employer contributions to 1 or more defined contribution plans—

(I) if such contributions do not exceed 6 percent of the compensation otherwise paid or accrued during the taxable year to the beneficiaries under such plans, this paragraph shall not apply to such contributions or to employer contributions to the defined benefit plans to which this paragraph would otherwise apply by reason of contributions to the defined contribution plans, and

(II) if such contributions exceed 6 percent of such compensation, this paragraph shall be applied by only taking into account such contributions to the extent of such excess.

In applying this paragraph, any single-employer plan covered under section 4021 of the Employee Retirement Income Security Act of 1974 shall not be taken into account.

In applying this paragraph, any multiemployer plan shall not be taken into account.