Aetna

(AET)

Friday became the latest insurance company to say it got a subpoena from New York prosecutors probing possible conflicts in the way the industry compensates brokers.

Aetna, a health-insurance provider, said it will cooperate fully with the inquiry, which began in April through the office of Attorney General Eliot Spitzer.

Aon

(AOC)

,

Marsh & McLennan

(MMC) - Get Report

and

Willis Group

(WSH)

previously disclosed receiving subpoenas.

Sources told

TheStreet.com

in April that

about a half dozen other companies might have been queried.

Several public interest advocacy groups have urged scrutiny of compensation deals in the insurance industry, saying they can create a conflict of interest between brokers and their own clients.