HARTFORD, Conn. - Connecticut Attorney General Richard Blumenthal is investigating the commercial debt rating industry for possible violations of antitrust laws.

Earlier this month, Blumenthal issued subpoenas to the three largest debt rating agencies -- Standard & Poors, Moody's Investor Services and Fitch Rating Services -- in an attempt to learn of any wrongdoing.

"The debt rating industry is a highly concentrated market controlled by a handful of companies," Blumenthal said. "Commercial credit raters occupy an essential positionin the debt market. Without a good credit rating many loans cannot be made."

Blumenthal is trying to figure out if the companies are exploiting their dominant positions (Standard & Poors and Moody's control about 80 percent of the market, Blumenthal says) to unfairly raise prices or exclude competitors.

Blumenthal's investigation will focus on:

-Allegations that some raters perform an unsolicited rating of an issuer's debt against its wishes, then demand the issuer pay for it or face a poor rating;

-Allegations that raters threaten to downgrade an issuer's debt unless they receive a contract to rate the issuer's entire debt pool;

-Exclusive contracts that feature discounts for issuers who have all their debt rated by a single agency; and

-The possibility that raters maintained their dominance in the market by providing higher debt ratings requested by debt issuers.