"Dear Ed," Mr. Greenberg and associates write in the letter. "We have reviewed the restructured government funding for AIG... Set forth below are some questions related to this announcement. Please respond to these questions as soon as possible. Investors in AIG securities need to know the answers to these questions and U.S. taxpayers should know how their tax dollars have been used."

In addition to asking where the parties got the $35 billion in cash collateral mentioned in a description of the CDS purchase entity deal, Greenberg and associates ask:

o What else was paid to those CDS counterparties?

o Who are those counterparties?

o How much of the $38 billion New York Fed lending facility has been drawn?

o How much of the drawn amount has been paid over to securities lending counterparties?

o Has that amount been paid to counterparties or has the cash been posted as collateral for the benefit of those counterparties?

o How much remaining exposure does AIG have in the securities lending business above the amount drawn on the New York Fed lending facility?

"Thank you in advance for providing answers to these critical yet simple questions," Greenberg and associates conclude in their letter.

AIG spokesman Joe Norton, when asked about Mr. Greenberg's letter responded, "We're very pleased with the new agreements that we announced in November with the Fed and the Treasury."

He said, "The new agreements give us new equity capital, substantially reduced debt, extended terms and lower interest rates and fees. We're open to all proposals that are in the best interests of AIG's shareholders."

This article updated, Dec.4, 9:23 a.m.