10 U.S.C. § 12007

The Secretary of the Army shall distribute the number of reserve commissioned officers, other than commissioned warrant officers, authorized in each commissioned grade between those assigned to reserve units organized to serve as units and those not assigned to such units. The Secretary shall distribute the number who are assigned to reserve units organized to serve as units among the units of each reserve component by prescribing appropriate tables of organization and tables of distribution. The Secretary shall distribute the number who are not assigned to such units between— (1) each special branch; and (2) all other branches taken together.