863. Can U.S. persons custody, offer for sale, serve as a transfer agent, and trade in covered securities? 

For purposes of E.O. 13959, as amended, activity by U.S. persons related to the following services are considered permissible, to the extent that such support services are not provided to U.S. persons in connection with prohibited purchases or sales: clearing, execution, settlement, custody, transfer agency, back-end services, as well as other such support services.