1.681(a)-1—Limitation on charitable contributions deductions of trusts; scope of section 681.
Under section 681, the unlimited charitable contributions deduction otherwise allowable to a trust under section 642(c) is, in general, subject to percentage limitations, corresponding to those applicable to contributions by an individual under section 170(b)(1) (A) and (B), under the following circumstances;
(b)
For taxable years beginning before January 1, 1970, if the trust has engaged in a prohibited transaction;
(c)
For taxable years beginning before January 1, 1970, if income is accumulated for a charitable purpose and the accumulation is (1) unreasonable, (2) substantially diverted to a noncharitable purpose, or (3) invested against the interests of the charitable beneficiaries.