Over 700 finance terms, Shmooped to perfection.
See covered party too. An affiliated person is someone who has special knowledge, relationships or hooks into a given public company so that they are treated different from Joe Sixpack the Plumber when transacting in securities of that company. If you are the CEO of GE, you obviously should be treated differently from Joe if you are buying or selling stock. The "affiliate" tag extends to board members, other C-level officers... and extends to "affiliated investor" restrictions for those who own more than 10% of the stock of the company (sometimes) and a bunch of other "privileged knowledge" people.