Yeah. Market makers cannot accept orders to buy or sell OTC stocks after 4pm E.T. Orders submitted by the broker after 4pm E.T. are handled as orders to be submitted to market makers at the opening of next trading day (9:30am E.T.). Execution and reporting of trades can happen after 4pm E.T., but not initiation of the trade (order to buy or sell). Off market trades, not using the OTC clearing facility, can occur after hours between dealers or brokerage firms.