Robert Rubin, once part of the Goldman Sachs wunderkind brigade, has retired from Citigroup, Bloomberg reports. Too bad he didn’t leave a little earlier. At his behest, Citigroup dove head first into subprime mortgage and related structure finance — investments that brought the bank to its knees — and nearly drive it out of business. According to a lengthy NYT story, Rubin was dismissive of his role in the fiasco saying he wasn’t involved in risk management at the bank. To me, he may as well have said, “Well, at Goldman Sachs we knew how to manage risk.” Well, buster, you weren’t at Goldman Sachs!