D.C. Mun. Regs. tit. 9, r. 9-203
If the donee for life or years has the right, in his or her sole discretion, to expend or consume the corpus, or a part of the corpus, for the donee's own use, the taxable value of the interest of the donee for life or years in that corpus, or that part of the corpus, shall be the value of the entire corpus or of that part of the corpus as may be so expended or consumed without reference to the method of determining the value of the life interest or of an estate for years as provided in § 202, except insofar as the market value of that part of the corpus as may be expended or consumed may be computed with reference to a fixed and definite standard, stated in the instrument creating the corpus, for the expenditure or consumption.
If the corpus may be expended or consumed in whole or in part by any person or persons for the benefit of, or on behalf of, a donee for life or years (whether or not the donee for life or years shall personally have the right of invasion or use), the taxable value of the interest of the donee for life or years in that corpus shall be the value of the entire corpus (or of that part of the corpus as may be so expended or consumed) without reference to the method of determining the value of a life interest or of an estate for years as provided in § 202, except insofar as the market value of that part of the corpus as may be expended or consumed may be computed with reference to a fixed and definite standard, stated in the instrument creating the corpus, for the expenditure or consumption.
To the extent which the corpus may be expended or consumed as set forth in this section, the future interest in the corpus shall be presumed to have no market value, unless, concurrently with the filing of the tax returns required to be filed for assessment purposes (for tax upon the interest of the donee for life or years and upon the future interest in the corpus), there is filed with the Deputy Chief Financial Officer tangible evidence relating to the age, life expectancy, state of health, accustomed scale of living, economic circumstances, and other sources of income of the donee for life or years.
The Deputy Chief Financial Officer may, in his or her discretion, require additional evidence prior to assessment for the purpose of determining the market value referred to in this section.
D.C. Mun. Regs. tit. 9, r. 9-203