The SEC states that, “An affiliate is a person, such as an executive officer, a director or large shareholder, in a relationship of control with the issuer. Control means the power to direct the management and policies of the company in question, whether through the ownership of voting securities, by contract, or otherwise. If you buy securities from a controlling person or ‘affiliate,’ you take restricted securities, even if they were not restricted in the affiliate’s hands.”
Further information can be found in this SEC article: Rule 144: Selling Restricted and Control Securities.