investment discretion.The ability of a person to (1) determine what will be purchased or sold by or for an account, (2) decide what will be purchased or sold by or for the account even though another may have the responsibility, or (3) influence the purchase or sale of securities or property in a way that, according to an administrative agency such as the Securities and Exchange Commission, should be subject to the agency’s governing rules and regulations.

[Blacks Law 8th]