NEW YORK (

TheStreet

) -- Swiss bank

UBS AG

(UBS) - Get Report

is being sued by a trustee representing victims of the Bernard Madoff ponzi scheme.

The lawsuit, filed in U.S. bankruptcy court, claims UBS and another firm,

Access International Advisers

(AIA), "are liable for at least $2 billion for their roles in masking

Madoff's fraud and perpetuating the Ponzi scheme, with an exact amount to be determined at trial."

E-mail messages to UBS spokespeople were not immediately returned and representatives for AIA could not immediately be reached.

Among the claims in the lawsuit is that two UBS feeder funds withdrew a total of $796 million in the 90 days preceding the Madoff bankruptcy after having taken out $1.12 billion in the previous six years.

The UBS Defendants disregarded the duties they publicly assumed and improperly delegated their primary functions to Madoff himself," the claim states.

--

Written by Dan Freed in New York

.

Disclosure: TheStreet's editorial policy prohibits staff editors, reporters and analysts from holding positions in any individual stocks.