Anglo Irish Bank Corp , a nationalized lender being wound down by Ireland's government after huge losses, on Monday won the dismissal of a lawsuit by a New York investment firm concerned it may lose its $200 million investment in the bank's debt.

U.S. District Judge Paul Gardephe in Manhattan said the January 2009 nationalization made the bank a foreign state for purposes of a U.S. law, the Foreign Sovereign Immunities Act of 1976, and that Ireland did not waive the bank's immunity from lawsuits.

The plaintiffs, two affiliates of Fir Tree Partners Inc, had sought a court order to block Anglo Irish from reducing their rights, and to force Anglo Irish to set aside at least $200 million to cover its obligations. They also sought the appointment of a receiver to insure payment.

Lawyers for Anglo Irish and Fir Tree had no immediate comment or were not immediately available for comment.

Anglo Irish merged this year with the Irish Nationwide Building Society (INBS) and is now called the Irish Bank Resolution Corp.

The decision could made it harder for investors to make cases against non-U.S. entities that have become wards of the state, in part as a result of the 2008 financial crisis.

Argentina invoked the 1976 law to shield its central bank and other entities it considers under state control against lawsuits stemming from its 2002 debt default.

Fir Tree said that after the nationalization, its interest in the $200 million of notes came under threat as Anglo Irish began to sell assets at steep discounts, including a U.S.-based loan portfolio, and set plans for the INBS merger.

Gardephe agreed that these actions were commercial in nature rather than sovereign.

Nonetheless he declined to take jurisdiction under an exception to the 1976 law for situations where non-U.S. commercial activity has a direct effect in the United States.

That exception does not permit jurisdiction over foreign states whose acts cause only speculative, generalized, immeasurable, and ultimately unverifiable effects in the United States, he wrote.

Ireland in 2010 received a 85 billion euro ($113 billion) bailout from the European Union and International Monetary Fund, in an agreement designed to force banks to sell assets and lessen their reliance on European Central Bank funding.

The case is Fir Tree Capital Opportunity Master Fund LP et al v. Anglo Irish Bank Corp, U.S. District Court, Southern District of New York, No. 11-00955.

(1 euro = US$1.331)

(Reporting by Jonathan Stempel in New York; Editing by Phil Berlowitz and Steve Orlofsky)