Rule D-10 defines a discretionary account as an account for which a municipal securities professional has been authorized to determine what municipal securities will be purchased, sold or exchanged by or for the account. The definition covers accounts for which a municipal securities professional exercises discretionary authority from time to time, as well as accounts in which the customer sometimes, but not always, makes investment decisions. Under rule D-10, a discretionary account will not be deemed to  exist if the professional’s discretion is limited to the price at which, or the time at which, an order given by a customer for a definite amount of a specified security is executed. The definition relates to discretion concerning what municipal securities will be purchased, sold or exchanged, rather than when or at what price such transactions may occur.