Md. Code, Labor and Employment § 3–503

An employer may not make a deduction from the wage of an employee unless the deduction is:

(1) ordered by a court of competent jurisdiction;

(2) authorized expressly in writing by the employee;

(3) allowed by the Commissioner because the employee has received full consideration for the deduction; or

(4) otherwise made in accordance with any law or any rule or regulation issued by a governmental unit.