The probe puts a spotlight on a rarefied world of billionaires who spend more than $1,000 for a bottle of wine. Some collectors claim they were sold counterfeit wines and have sued suppliers or sellers of the vintages, including one linked to Thomas Jefferson's private collection.

The disclosure of the November subpoena by Sotheby's, the world's second-largest auction house, followed confirmation by rival Christie's International yesterday that it had been subpoenaed for information on wine sales. The investigation is being headed by the Federal Bureau of Investigation in Manhattan, according to a person familiar with the matter.

``A lot of consumers aren't aware of the problem,'' said David Gordon, the wine director at the Tribeca Grill in Manhattan. ``There's too much rare wine in the pipeline, more than what you'd think is made, and there's no oversight.''