[ajmurmann]

A while ago some article had a great example of what can happen if the majority of shares of most companies in the same industry are held by the same investors: It punishes competition within the same industry. The example was about the airline industry where investors don't want airlines to go head to head on pricing. While some companies might benefit from this, it would lead to lower margins and thus profits for the industry as a whole. So this in essence might form a cartel.