The nation's third-largest health insurance company is the latest to leave the individual policy market in Indiana in another sign of diminishing competition to benefit consumers who purchase policies through a state insurance exchange under the federal healthcare overhaul. Aetna Inc. informed the Indiana Department of Insurance in an April 29 letter that it intends to cancel all individual policies on Dec. 1. The letter was made public last week in a letter from Deputy Insurance Commissioner Robyn Crosson to the Centers for Medicaid and Medicare Services and posted on the state's federal health care overhaul website. Aetna spokesman Scot Roskelly said Wednesday the carrier currently has only 700 individual health insurance policies in Indiana, making up only a small fraction of the market, and will remain in other sectors, including small group coverage. "The administrative costs of overseeing just 700 members are relatively high," Roskelly said.