RE: RNS23 Nov 2016 19:32
SiJew: There are various rules relating to disclosure and transparency of share ownership, i.e. who owns how many shares and how this ownership is communicated. To simplify the rules somewhat, "A person must notify the issuer (in this case RCN) <,..> if the percentage of those voting rights reaches, exceeds or falls below 3%, 4%, 5%, 6%, 7%, 8%, ..." It's then up to the issuer, i.e. RCN, to submit a TR-1 form notifying everyone of the change.
Have a look for "DTR 5 Vote Holder and Issuer Notification Rules" for the gory details.
So looking at this evenings RNS, we learn that John Stanislas Albert Radziwill Humble Trading Limited increased their holding from approx. 8.7million to 10.2million, crossing the 6% threshold and triggering the TR-1. They now have 6.98%, so if they buy a few more then RCN will have to issue another TR-1 when the 7% is crossed.