Maryland Code, Commercial Law § 17-306

All intangible personal property and any income or increment on it, held in a fiduciary capacity for the benefit of another person, is presumed abandoned unless, within 3 years after it becomes payable or distributable, the owner has increased or decreased the principal, accepted payment of principal or income, corresponded in writing concerning the property, or otherwise indicated an interest as evidenced by a memorandum on file with the fiduciary.