D.C. Code § 47-2805.01
The Mayor of the District of Columbia shall fix the period for which any license authorized under this subchapter may be issued in a manner consistent with the uniform master [basic] business licensing expiration date provisions as set forth in § 47-2851.09. Licenses issued at any time after the beginning of the license period as set forth in § 47-2851.09 shall date from the first day of the month in which the license was issued and end on the last day of the license period above prescribed, and payment shall be made of the proportionate amount of the bi-annual license fee or tax; provided that where the license fee is $3 or less the fee shall not be prorated; and provided further, that no fee or tax shall be prorated to an amount less than $3.
D.C. Code § 47-2805.01