* YPF accused of hiding risk of nationalization
* Majority stake seized from Repsol in April 2012
Feb 6 (Reuters) - YPF SA, the Argentina energy company seized by that country's government last year, was sued in the United States on behalf of investors who allegedly were not warned of the risks of nationalization prior to a March 2011 securities offering.
In a complaint filed Tuesday in the U.S. district court in Manhattan, a Michigan pension fund said YPF and its underwriters made false statements and omitted key facts from a prospectus and other documents for the company's roughly $1.07 billion offering of about 26.2 million American depositary shares.
Other defendants include YPF executives and directors; Spain's Repsol SA, which once had a majority stake in YPF; and the investment banks Credit Suisse Group AG, Goldman Sachs Group Inc and Morgan Stanley. Argentina is not a defendant in the case.
The Michigan fund, Monroe County Employees' Retirement System, said YPF harmed shareholders by failing to disclose that it had faced a heightened risk of nationalization.
It said this should have been disclosed because of YPF's failure to "adequately" produce oil and gas in Argentina, failure to reinvest enough profit into operations and breach of contracts with various Argentine provinces.
Argentine President Cristina Fernandez last April 16 announced the seizure of a 51 percent YPF stake from Repsol, saying that oil and gas company did not invest enough and let oil production and exploration decline.
The complaint said the price of YPF's ADSs closed two days later at $13.12, or 68 percent below their $41 offering price.
It seeks class-action status on behalf of the ADS purchasers, money damages and other remedies.
YPF, Repsol and Credit Suisse did not immediately respond to requests for comment. Goldman and Morgan Stanley representatives declined to comment. Repsol last May separately sued Argentina over the YPF seizure.
The case is Monroe County Employees' Retirement System v. YPF SA et al, U.S. District Court, Southern District of New York, No. 13-00842.