UnitedHealth Group Inc., the biggest U.S. health insurer, will face a fragmented regulatory landscape in 2014 after the first approved state insurance marketplaces are launched as part of the health care overhaul.

Rules for the six state insurance exchanges that won conditional approval from the Obama administration Dec. 10 are split evenly between those with strict criteria for companies that want to participate and others that intend to open their exchanges to all comers, a scenario supported by the insurance industry.

A high bar for inclusion could limit the number of insurers offering health plans in some states.

The exchanges are the heart of the 2010 Affordable Care Act's plan to expand health care to 30 million people -- including more than 1 million in Minnesota. States have less than a year to open online platforms where local residents and small businesses, with the help of federal tax credits, can shop online for insurance.

The approved states are Connecticut, Maryland, Colorado, Oregon, Massachusetts and Washington, all led by Democratic governors. Minnesota has submitted its blueprint plan, but has yet to hear back from federal officials.

"The challenge is it's all new," said Kim Holland, executive director for state affairs at the Blue Cross Blue Shield Association, a Washington-based trade group that represents 38 state insurance plans. "We have a really, really short period of time in order to get everything done."

Enrollment in the exchanges must begin by Oct. 1, 2013, for plans that will take effect Jan. 1, 2014.

In Connecticut, regulators are taking a strict approach by making insurers meet requirements for patient access to doctors that exceed those of the federal Affordable Care Act. Insurers will have to make two-year commitments to participate in the Connecticut exchange, and include almost all of the state's U.S.-funded health clinics in their networks.

"The board saw its role as being very, I'd say, passionate about supporting consumers and trying to establish standards where health plans could reach to a slightly higher bar than required in the ACA," said Kevin Counihan, CEO of the Connecticut exchange.

At the same time, Maryland said it's letting any plan that meets federal standards sell coverage at the start as the state rushes to craft a marketplace that will be popular with both consumers and insurers.

"What we're focused on in the initial couple of years is really getting as many people enrolled on the exchange as possible," said Rebecca Pearce, executive director of the Maryland exchange. "To do that we need to make sure we have as many carriers as possible."

Insurers are worried about measures that might create "an un-level playing field," according to Holland, a former Oklahoma insurance commissioner. "Anything that would create market variation or lack of consistency would be problematic."

Daryl Richard, a UnitedHealth spokesman, said the Minnetonka-based company is in the process of researching how each of the states' exchanges may be structured.

"Given the regulatory variation from state to state -- and many states have not yet formalized their exchange models -- we have not yet made any decisions about where we will be offering our health plans through the exchanges," Richard said.

UnitedHealthcare CEO Gail Boudreaux told the Star Tribune that the company is transforming its insurance business to prepare for a consumer-centric approach, which will play out directly on exchanges where customers can easily compare plans.

Coming up with a "modern benefit design" is one piece of many needed "to change the structure of health care and cost curve," Boudreaux said.

UnitedHealth is not the only for-profit insurer looking at the exchanges warily, said Robert Zirkelbach, a spokesman for America's Health Insurance Plans, the industry's lobbying group in Washington.

The group has generally opposed practices like those of Connecticut, a model called "active purchasing" through which some insurers may be excluded from selling their plans, he said.

Maximizing choice

"There's already variation in how health insurance is regulated state by state," Zirkelbach said. "The important thing is how the exchanges are structured, ensuring they're done in a way that will maximize choice and competition for consumers and employers."

States with extra rules run the risk that insurers will skip their exchanges, said Ana Gupte, an analyst with Sanford C. Bernstein & Co.

"I'm sure the insurance industry will go in with good faith of wanting to play everywhere they possibly can, but they can always reduce their effort and involvement over time," she said in a phone interview. "It's a balance, because you do want the large publicly traded players and the big Blue Cross Blue Shield to all be there, in addition to the smaller not-for-profits."

A majority of the remaining 50 states may let the United States run the exchanges or choose to provide services such as consumer assistance as partners with the federal government.

Twenty-two governors, all Republicans, have sent notice that they won't build their own exchanges. The rest had until Friday to decide.

No more than three or four additional states are expected to build exchanges themselves, according to Bryce Williams, a managing director at the consulting firm Towers Watson.

Nationwide, health plans will be required to meet certain minimum qualifications for participating in the exchanges, such as offering sufficient networks of doctors and hospitals and meeting federal limits on out-of-pocket costs. The law lets states set additional rules.

Star Tribune staff writer Jackie Crosby contributed to this story.