Now selling like hotcakes at Saks Fifth Avenue: ringside seats to a creditor-on-creditor cage match. You may have seen Saks Global’s announcement last week that it was able to raise a fresh $600 million from its existing bondholders, many of the very same people who have suffered a 65 percent loss on bonds they bought just last December. And you may have asked yourself: Why in the world would anyone who has already lost 65 percent of their money owning part of a $2.2 billion bond, used to finance Saks’s purchase of Neiman Marcus Group, want to put up more money to rescue Saks Global from its dire financial predicament? Why throw good money after bad?