Cardinal Health Inc.(CAH) on Friday said it received a subpoena from New York state's attorney general as part of a broad industry probe into a segment of the drug wholesaling industry.

The announcement in a regulatory filing comes a day after AmerisourceBergen Corp. (ABC) disclosed the probe and said it had been subpoenaed by the New York attorney general's office on Wednesday.

Both Cardinal and AmerisourceBergen said the probe by the Office of New York State Attorney General Eliot Spitzer (search) was related to purchases of pharmaceuticals from other drug wholesalers, which is known as the alternate source market. The two companies each said that they were among multiple parties to be subpoenaed by Spitzer's office.

The identity of other parties was not disclosed.

Cardinal said it will be fully responsive to requests by the New York attorney general.

AmerisourceBergen said it has not been advised on any allegations of misconduct.

JP Morgan analyst Lisa Gill, in a research note, said the drug purchases from the secondary market account for less than 0.5 percent of drug sales.

Gill said she believes the probe is part of a wider-ranging investigation into the safety of the drug supply channel and the source of counterfeit drugs on the market.

Shares of AmerisourceBergen fell to $58.26 in premarket trade on the Inet brokerage, after closing on Thursday at $59.20 on the New York Stock Exchange. Shares of Cardinal Health closed at $56.83 Thursday on the NYSE.