When you mention large shareholders,are u thinking that they hold 30,40 50 mio shares? If so they must apply the 13d 5% rule that requires fileing(sec) of holdings or are u thinking that amounts are much smaller?
Under the reporting requirements. There are ways of getting large numbers of shares into an entity to go under the reporting requirements (not saying they do that). One way is to split shares up amongst different people within one entity for payment of services/compensation, etc.