Maged, I do think that the knowledge that more than one shareholder was trying to sell their stake in GLBSE would likely have affected people's confidence in the exchange.  When people thought that theymos was the only one selling his stake and that he was doing so for ideological reasons, it was reasonable to assume that there was a unity of purpose among the remaining shareholders.  People may well have made different decisions about doing business with GBLSE if that theymos was not the only shareholder looking to bail out

While I know that the "private company" line has been trotted out, more information about the shareholders would have been publicly available if GBLSE was in fact a private company.  People could have pulled the Company House documents and confirmed for themselves who the office-holders are, who the office-holders are, the paid up capital, etc - people have done exactly that in respect of Intersango (an actual privately owned company) in the past.

I do think that not informing people that other share-holders were looking to divest their equity in GLBSE may have led to users retaining a level of confidence in GLBSE which was unwarranted and that the loss of confidence which would likely have followed disclosure of full truth would have been reflected in prices of not just GLBSE's stock but also the stock of its asset-issuers.