D.C. Mun. Regs. tit. 26, r. 26-C2606
Interest shall be computed on the actual amount of the loan and shall not be charged or received to any greater rate than the maximum legal rate applicable to the loan of money.
No lender or licensee shall charge or receive any unaccrued interest on a loan of money.
No licensee shall accept as evidence of indebtedness of a borrower, or as an instrument of security for a loan of money, any evidence of indebtedness, instrument of security or other paper writing the face amount of which is in any amount greater than the actual amount of the loan; Provided, that licensees are authorized to accept as evidence of indebtedness and as instruments of security for loans of money paper writings the face amounts of which include, in addition to the actual amount of the loan, a premium on insurance specifically authorized by this chapter.
D.C. Mun. Regs. tit. 26, r. 26-C2606