WASHINGTON BUREAU — Connecticut Insurance Commissioner Thomas Sullivan resigned Monday and will be taking a job in the Hartford office of PricewaterhouseCoopers L.L.P., officials say.

Debra Korta, a representative for the Connecticut department, says Sullivan submitted a letter of resignation to Gov. Jodi Rell Monday. She says he will start the job at PricewaterhouseCoopers Nov. 15.

It is unclear when a new commissioner will be appointed. Rell’s term expires Jan. 5.

In a copy of the Sullivan resignation letter released by the Connecticut department, Sullivan does Sullivannot say why he is resigning. Sullivan says he takes pride in accomplishments such as accelerating the insurer licensing process, introducing an online licensing payment system, and reducing a backlog of paperwork in the department’s property-casualty division.

Sullivan, a former insurance industry executive, was appointed Connecticut insurance commissioner in 2007. He has been active in the National Association of Insurance Commissioners (NAIC), Kansas City, Mo., and he has been the 2010 chair of the NAIC’s Life Insurance and Annuities Committee.

Sullivan was a strong defender of retained asset accounts (RAA) when they came

under fire several months ago from veterans’ groups, the U.S. Department of Defense, the U.S. Veterans Department and several House committees.

In recent weeks, Sullivan has faced harsh criticism for a decision to approve a health insurance rate increase request.

Sullivan approved a request by Anthem Blue Cross and Blue Shield of Connecticut, a unit of WellPoint Inc., Indianapolis (NYSE:WLP), to increase rates on some new health insurance policies by 47%.

Sullivan drew fire for the decision from Connecticut Attorney General Richard Blumenthal, who is a Democratic candidate for the Senate; consumer groups; and the U.S. Department of Health and Human Services (HHS).

Jay Angoff, director of the HHS Office of Consumer Information and Insurance Oversight, demanded in an Oct. 18 letter that the Connecticut Insurance Department hold a hearing on the Anthem increase, “test and validate the assumptions underlying the increase and make all data filed by Anthem public.”

“At a time when American families are struggling to meet their most basic needs, these rate hikes could lead a number of residents of your state to lose their health coverage,” Angoff charged in the letter.

Sullivan defended the rate hike–the largest in state history–by contending that the new Affordable Care Act, the legislative package that includes the Patient Protection and Affordable Care Act (PPACA), has imposed expensive new mandates on insurers.