Maurice "Hank" Greenberg, the terminally outspoken former CEO of American International Group, Inc. (AIG: sentiment, chart, options), has penned yet another incendiary missive to the company's new chief executive, Edward Liddy. In a letter dated Monday, Greenberg wrote, "One of the Maiden Lane special purpose vehicles purchased approximately $50 billion of CDOs at par... and obviously canceled the default swaps. It is hard to believe that the counterparties would be carrying the CDOs at par and not have marked them to market. If so, what is the rationale for buying them back at par?"

Greenberg observed that the transaction, as he understands it, "certainly seems... very good for the counterparties." He added, "I am sure I am missing something, and I would be more than interested in finding out what transpired." (Is it just me, or is this last comment rife with passive aggression?)

The former CEO and current stakeholder in AIG ended his letter with an apparent jab at Liddy, and some no-doubt unsolicited advice. In a postscript, Greenberg suggests that a conversion of AIG's government loan "would make it possible to attract private capital and put in a proper management team to rebuild the company."

Of course, Liddy may have been asking for the veiled insult. The current CEO recently observed that Greenberg "didn't keep us contemporary" and "may have stayed too long."

As its past and present CEOs continue to bicker, AIG is trading near breakeven at $1.75. The former Dow component has shed 97% of its value year-to-date.