Those buying Affordable Care Act benefits for 2015 on the Maine health insurance marketplace will see either a small decrease in average premium costs from this year’s prices or no change, according to filings with the Maine Bureau of Insurance.

The state insurance bureau finalized rates Sept. 5. While the rates still await approval by the U.S. Centers for Medicare and Medicaid Services, the federal government mostly defers to the states when setting rates, bureau spokesman Doug Dunbar said.

The health insurance marketplace is where individuals who don’t have insurance through an employer — often part-time workers or the self-employed — can buy subsidized insurance. The marketplace is a key part of the ACA, which is designed to reduce the number of people who are uninsured. Despite a shaky rollout last fall caused by the malfunctioning website, more than 44,000 Mainers bought insurance for 2014 on the marketplace.

Maine Community Health Options, a new co-op formed under the law, captured more than 80 percent of the Maine market in the first year that subsidized insurance was available. For 2015, average rates will be the same for the insurer’s customers.

Customers of Anthem Blue Cross Blue Shield, the only other insurer on the marketplace this year, will see average premiums decline 1.1 percent. A third insurance company, Harvard Pilgrim Health Care, will join the Maine individual health insurance marketplace for 2015.

“I think it’s a great thing for consumers,” said Kevin Lewis, CEO of Maine Community Health Options. “Competition can bring out the best for consumers.”

Anthem spokesman Rory Sheehan said the company is committed to the health insurance marketplace for the long haul.

“We are pleased to have filed for an average rate decrease of 1.1 percent,” he said. “We look forward to welcoming new (marketplace) members when open enrollment starts in November.”

Because the federal government subsidizes premiums for people earning between 100 percent and 400 percent of the federal poverty level, or between $23,850 and $95,400 this year, premium costs vary greatly. Also, deductibles and maximum out-of-pocket costs vary depending on the plan chosen.

However, when factoring in subsidies, a typical premium cost is about $150 or less per month.

Mitchell Stein, an independent health policy analyst based in Cumberland, said that in many ways insurance premiums reflect nationwide trends in health care costs. The sluggish economy is keeping inflation in check, which is one reason health care costs have been kept down.

Stein said the ACA’s Medicare reforms also are a factor, as that program is starting to change the way health care providers are paid by reimbursing hospitals and doctors for quality care and keeping patients healthy instead of for every test or treatment. The fee-for-service system was blamed for accelerating health care costs, for example, by encouraging hospitals to use expensive medical devices as often as possible.

“It’s having a spillover effect,” Stein said. “These Medicare reforms that are changing the way health care providers are compensated are changing behaviors. If a doctor is making a change for Medicare patients, the doctor is likely making the same change for all patients.”

The enrollment period for 2015 insurance is Nov. 15 to Feb. 15.