Quadrangle Group, which was not long ago America's most prominent media-focused private equity firm, is folding (in its current form, at least). The reason for its downfall is the same man largely responsible for its success: Steven Rattner.

The New York Post reports today that Quadrangle is winding itself down and will try to "reinvent itself under a new name." But it's not just a PR move: two top executives are leaving the firm, and the new version will reportedly "be more focused on managing client assets," a somewhat safer game than Quadrangle's past of PE investments in high profile media companies including MGM, Adelphia, Cablevision, Mail.com, and Alpha Media Group. The firm's assets under management and headcount are both down by half or more since their peak, the Post says.

But the real problem, of course, is Steven Rattner, the former NYT reporter turned financier who made Quadrangle what it was. Rattner's short-lived turn as Car Czar spoke to his own aspirations towards power; Mike Bloomberg used to let Quadrangle manage billions of dollars for him. All of that was torpedoed by a bribery scandal, and now Rattner is facing a suit by the SEC and the possibility of a lifetime ban from the securities industry.

The staff of Quadrangle will probably come out just fine. But the name itself is tainted by its connection to Rattner. It's fascinating to see a man rise so far and then fall so fast. Don't get depressed, Steve; you can always become the next Henry Blodget.

[Photo via AP]