The Purchasing and Materials Management (PMM) Department of the Alameda – Contra Costa Transit District conducts all purchasing activities for AC Transit.

PMM develops and issues solicitations for all goods, inventory items, services, and public works (construction) projects. The Buyers (generic for Contract Specialists, Senior Buyers and Buyers) employed in PMM are responsible for these purchasing activities and are the primary point of contact for vendors to resolve contractual differences and issues amendments to existing contracts. The Buyer is also available to meet with a firm whose proposal was not selected to debrief them on their proposal's strengths and weaknesses.