Greenberg has also filed suit in the Federal Court of Claims in Washington against the Treasury Department on similar grounds.

In the latest response, filed Friday, lawyers for Greenberg contend that the Fed is wrong in stating that it has immunity from claims incurred in all of its actions regarding AIG.

“In sum, there is no basis for dismissing this case at this preliminary stage, and FRBNY's motion [to dismiss the case] should be denied,” the Greenberg response says.

The suit contends the FRBNY breached its fiduciary duty to AIG shareholders “when it caused AIG to take actions which helped third parties and furthered FRBNY's goals unrelated to FRBNY's core statutory purpose: lending.”

The answer by Greenberg's lawyers says that the FRBNY is wrong in contending that, because it lent and exercised control as part of a rescue operation, “it was freed of any duty whatsoever to the loan-receiving entity or its common stock shareholders.”

Greenberg's lawyers says the FRBNY is arguing that all fiduciary duties are preempted, and appears to contend that it is also subject to no constitutional constraints.

The lawyers state, “FRBNY is not correct, and indeed its argument fundamentally misapprehends the nature of the claims against it.”

In its April answer, the Fed said the complaint should be dismissed without further imposition of burdens on the Federal Reserve Bank of New York, “and, ultimately, taxpayers.”

The Fed response added that, “Although the complaint downplays AIG's plight as 'a liquidity problem, not a solvency problem', the 'liquidity problem' was gargantuan and threatened AIG with bankruptcy.”

Greenberg took back Starr, a Switzerland-based firm, as part of an earlier settlement of claims he made against the federal government. Greenberg was ousted from AIG by directors in 2005, and at that time initiated litigation against the company.