D.C. Mun. Regs. tit. 9, r. 9-120
A common trust fund (as defined by Pub. L. 81-416) shall not be subject to income taxes imposed by the Act, as amended, and for purposes of the Act shall not be deemed to be a corporation.
While a common trust fund, as such, is not taxable for income tax purposes, the interest of a participant in a common trust fund shall be taxable, if it would be otherwise taxable under the provisions of Title 9 of the Act.
The net income of a common trust fund shall be computed in the same manner and on the same basis as the net income of an individual.
In computing its net income, each participant of a common trust fund shall include its proportionate share of the net income of the fund, whether or not distributed to it, and the amount so included in the net income of a participant shall be taxable to that participant or its beneficiary in the manner and to the extent provided in Title 9 of the Act as if any amount not distributed to the participant during its taxable year actually had been so distributed.
Each bank or trust company maintaining a common trust fund shall make a return under oath for the taxable year of the fund.
D.C. Mun. Regs. tit. 9, r. 9-120