See Reg 1.1014-5(a): (2) Except as provided in paragraph (b) of this section, the proper measure of gain or loss resulting from a sale or other disposition of an interest in property acquired from a decedent is so much of the increase or decrease in the value of the entire property as is reflected in such sale or other disposition. Hence, in ascertaining the basis of a life interest, remainder interest, or other interest which is sold or otherwise disposed of, the uniform basis rule contemplates that proper adjustments will be made to reflect the change in relative value of the interests on account of the passage of time. (3) The factors set forth in the tables contained in §20.2031-7 or, for certain prior periods, §20.2031-7A, of Part 20 of this chapter (Estate Tax Regulations) shall be used in the manner provided therein in determining the basis of the life interest, the remainder interest, or the term certain interest in the property on the date such interest is sold. The basis of the life interest, the remainder interest, or the term certain interest is computed by multiplying the uniform basis (adjusted to the time of the sale) by the appropriate factor. In the case of the sale of a life interest or a remainder interest, the factor used is the factor (adjusted where appropriate) which appears in the life interest or the remainder interest column of the table opposite the age (on the date of the sale) of the person at whose death the life interest will terminate. In the case of the sale of a term certain interest, the factor used is the factor (adjusted where appropriate) which appears in the term certain column of the table opposite the number of years remaining (on the date of sale) before the term certain interest will terminate