Which institutional investor should I specifically be concerned about? Show me the institutional investor that owns 30% of American, 30% of Delta, 30% of South

Which institutional investor should I specifically be concerned about? Show me the institutional investor that owns 30% of American, 30% of Delta, 30% of Southwest, and 30% of United. [1] If this is the case, then yes we have a problem. The manager of this fund has a major incentive to have these 4 major firms collude and price gouge its customers, as competition among the firms would minimize profit for the index fund. It would major shares of the companies that own the entire market. I think it's safe to say that this institutional investor doesn't exist. Which concentrated group of 3-4 (oligarchy) institutional investors own a combined 50% of American, 50% of Delta, 50% of Southwest, and 50% of United? If this is the case, then yes, we have a problem. Collusion will occur between these funds, who will agree to use their voting/management rights to collude at the airline level, as they own the companies that own the market. We're usually used to seeing collusion between the CEO's and boards of major companies in concentrated markets because we tend to think of these people as the people who profit the most from price gouging. Antitrust lawsuits against AT&T, Kodak, Standard Oil - these are all pretty concrete examples of collusion from brands that we (used to) interface with. [2] Now we could be seeing collusion abstracted one layer - the owners/shareholders are institutional investors who don't have a well-known brand. Which institutional investors specifically should we be worried about? Unlike AT&T + Verizon, I don't interface directly with any of them, so I'm not sure which firms I should be concerned about. Where's the data? [1] 30% is an arbitrarily large number. [2] http://www.hg.org/article.asp?id=6025 http://www.hg.org/article.asp?id=6025