How do I begin quoting/trading OTC securities? ?Top Only FINRA registered broker-dealers may quote and trade OTC securities. “Market Making” firms may quote and trade while “Order Entry” firms may only trade. FINRA determines the broker-dealer’s status. Once FINRA has assigned your firm a Market Participant Identifier (MPID), you may contact OTC Markets Group's Trading Services department at tradingservices@otcmarkets.com or 800.LIST.OTC to begin the enrollment process.