Credit rating agency A.M. Best has revised its outlook for Golden Valley-based PreferredOne due in part to the health insurer's troubled business through the MNsure exchange.

A.M. Best affirmed the financial strength rating of B++ (Good) and the issuer credit ratings of "bbb" for PreferredOne Insurance Co., and an affiliated HMO. But the agency revised the outlook to negative from stable.

A.M. Best said it subsequently withdrew the ratings in response to PreferredOne's request to no longer participate in the ratings process.

In a prepared statement, Preferred​One noted that A.M. Best affirmed the insurer's "current secure rating," and the company added: "There was no actual rating change."

"We have seen that, overall, the purchasing community has not valued an independent rating as a key criteria in selecting and retaining carriers," the insurer said. "In fact, two other main insurance carriers in the market do not have any A.M. Best rating."

During the first year of the state's exchange, PreferredOne sold individual market coverage at premiums that in many categories were the lowest in the nation. The prices helped the insurer capture about 60 percent of the business on MNsure.

But in September, PreferredOne said it would not be an option on the exchange for 2015, calling its MNsure business unsustainable. In October, the company said it was increasing individual market premiums by an average of 63 percent next year.

In its statement, A.M. Best said it was concerned that underwriting results might be slow to improve.

"The rating action reflects the group's weakened underwriting and operating performance in 2014," A.M. Best said in a news release. "This decline is primarily due to higher utilization, high claims experience and pricing issues surrounding the individual membership added this year through the Minnesota health insurance exchange, MNsure."

Earlier this week, PreferredOne said Marcus Merz, its longtime CEO, is retiring.

Christopher Snowbeck • 612-673-4744

Twitter: @chrissnowbeck