Minnesota health insurers posted mixed financial results for 2014, as carriers adopted different strategies in response to changes with the federal Affordable Care Act.

Minnetonka-based Medica, Minneapolis-based UCare and Eagan-based Blue Cross and Blue Shield of Minnesota saw more operating income in 2014 than during the previous year, according to regulatory filings this week.

But operating income was down at Bloomington-based HealthPartners, and operating losses widened at Golden Valley-based Preferred­One.

The financial results cover the health plans' revenue and operating income from "fully-insured" customers, meaning individuals and groups that pay the insurers to take the financial risk for claims costs. The results also reflect the health plans' business with the Medicare, Medicaid and MinnesotaCare government health insurance programs.

But the figures don't include fees from larger employers that hire the companies as third-party administrators for "self-insured" health plans, where employers take financial risk for medical claims.

Of the five insurers — which collectively dominate the state's fully-insured market for health coverage — Medica saw the biggest year-over-year increase in operating income, which grew to about $123.5 million on $3.38 billion in revenue. In 2013, operating income at Medica was about $14.3 million on roughly $3.2 billion in revenue.

The improved results were driven in part by a favorable settlement from prior years with the federal Medicare health insurance program. Medica operates a large Medicare health plan in which payments from the government program are reconciled after-the-fact based on the insurer's costs, said Larry Bussey, a Medica spokesman.

Unlike PreferredOne, Medica did not make a splash during the first year of the state's MNsure health exchange by offering low-premium policies in the individual market.

"We've been trying to play a long game, and maintain stability and strong performance through this period as the market kind of settles out," said Bussey, whose company employs about 1,400 people.

UCare entered the market for individuals who bought non-group coverage for the first time in 2014, but the change wasn't the key driver for improved operating income last year. Instead, the HMO said that membership grew by about 45 percent, with much of the increase coming from state public programs.

For the year, UCare posted operating income of about $95.3 million on revenue of roughly $3 billion.

At HealthPartners, revenue increased by about 5 percent last year to nearly $3.4 billion, but operating income of about $69 million was down from 2013. The insurer spent more on medical care for people in Medicare and Medicaid products, while posting a $5 million loss on its Medicaid business, said spokesman Vince Rivard.

The financial results don't include the growing network of hospitals at HealthPartners.

Blue Cross posted a small amount of operating income from its fully-insured business in 2014, as opposed to a slight loss the previous year. The improvement mirrored overall financial results for the insurer's parent company, Aware Integrated Inc., which Blue Cross released Wednesday.

For 2014, the parent company posted an operating loss of $8.2 million on $10.1 billion in revenue, which was better than the previous year's operating loss of about $29.5 million. Blue Cross employs about 3,500 people.

"We knew that 2014 would be a challenging year, as the market continued to go through significant transition related to health reform," said Michael Guyette, president and chief executive at Blue Cross, in a statement.

In March, the Star Tribune reported that PreferredOne's insurance division posted an overall loss of about $20.9 million last year. Company officials cited unsustainable growth in the individual market.

Christopher Snowbeck • 612-673-4744

Twitter: @chrissnowbeck