Italian tax authorities are looking into undeclared holdings in Switzerland and elsewhere owned by Fiat SpA’s Agnelli family.

The country’s tax agency confirmed a report by the TG5 television station that an investigation has been opened into the Agnelli holdings involving some EUR2 bn (US$2.84 bn) in undisclosed family assets.

Il Giornale newspaper reported that the assets include art works, equities and U.S. real estate, as well as cash deposits. The Agnelli family could be liable for fines exceeding the total value of the holdings, according to the newspaper.

Bloomberg News notes that Margherita Agnelli, the only surviving child of Fiat’s late Honorary Chairman Giovanni Agnelli, filed a lawsuit in 2007 alleging that family advisers withheld information about part of her father’s fortune that should have been distributed to heirs. The suit is still pending in a Turin court.

The Agnelli family controls Fiat through its EXOR SpA holding company. An Exor spokesman said neither the holding nor its Chairman John Elkann are implicated in the probe, which involves the direct heirs of Giovanni Agnelli: his wife Marella and the couple’s daughter Margherita, who is Elkann’s mother.