New York subpoenas five energy companies

New York Attorney General Andrew Cuomo has subpoenaed five energy companies - AES Corp, Dominion, Dynegy and Xcel Energy and coal producer Peabody Energy - for internal documents.

Cuomo is questioning whether the companies' investors had been fully informed about the possible financial, regulatory and litigation risks resulting from carbon emissions from planned coal-fired power plants.

Several states and the US Congress are pushing for carbon emissions regulation, which could raise costs for