D.C. Code § 28:3-112
2. The purpose of subsection (b) is to clarify the meaning of “interest” in the introductory clause of Section 3-104(a). It is not intended to validate a provision for interest in an instrument if that provision violates other law.
1. Under Section 3-104(a) the requirement of a “fixed amount” applies only to principal. The amount of interest payable is that described in the instrument. If the description of interest in the instrument does not allow for the amount of interest to be ascertained, interest is payable at the judgment rate. Hence, if an instrument calls for interest, the amount of interest will always be determinable. If a variable rate of interest is prescribed, the amount of interest is ascertainable by reference to the formula or index described or referred to in the instrument. The last sentence of subsection (b) replaces subsection (d) of former Section 3-118.
Mar. 23, 1995, D.C. Law 10-249, § 2(d), 42 DCR 467
1981 Ed., § 28:3-112.