However, if you own a share then you should legally be recorded with the CAA as a registered owner (see the Trustee form link above). If you own a share in an aircraft, but it's registered to someone else's Limited company, you would have virtually no say in the matter if that Director decided to sign ownership of the aircraft away to himself and run away with the money!
I am talking about a group formed and registered with the CAA as a limited company ( a very common arrangement) and where the owners of the aircraft are shareholders in the company.
A director can no more run away with the shareholder's aircraft or money under this arrangement than he/she could under any other arrangement.