Bank of America, JPMorgan Chase, Citigroup and Wells Fargo are among the major banking companies involved in the inquiry by the office of Benjamin M. Lawsky, the superintendent of New York State's Department of Financial Services. This is done according to a person who briefed on the investigation and wanted to remain unidentified because the matter was confidential. Mr. Lawsky's office issued 31 subpoenas or other legal notices related to the case in early October, just as the state's insurance and banking departments were merged under his new agency.