Md. Code, Insurance § 15–1608

A pharmacy benefits manager shall maintain adequate books and records about each purchaser for which the pharmacy benefits manager provides pharmacy benefits management services:

(1) in accordance with prudent standards of record keeping;

(2) for the duration of the agreement between the pharmacy benefits manager and the purchaser; and

(3) for 3 years after the pharmacy benefits manager ceases to provide pharmacy benefits management services for the purchaser.