mmm.. I don't get your point. Even in an open auction, bidders in an auction could still collude to submit lower bids and divide their winnings.
Problem is that there are only a couple of large banks who control a large portion of money. If there were more banks, one bank will eventually break the collusion and offer a competitive bids, and other banks will follow.
Problem is that there are only a couple of large banks who control a large portion of money. If there were more banks, one bank will eventually break the collusion and offer a competitive bids, and other banks will follow.