NEW YORK (Reuters) - Aetna Inc will exit Iowa’s Obamacare-compliant individual insurance market in 2018, a year surrounded by uncertainty over which insurers will sell plans and at what price as Republicans seek to dismantle the 2010 Affordable Care Act.

FILE PHOTO - A trader points up at a display on the floor of the New York Stock Exchange August 20, 2012. REUTERS/Brendan McDermid/File Photo

President Donald Trump has promised to repeal and replace former President Barack Obama’s signature piece of domestic policy, often called Obamacare, but has been stalled by Republicans disagreeing over possible changes.

Many insurers are waffling over where to sell insurance plans in 2018. They worry that Republicans have not said they will extend billions of dollars of subsidies into 2018 and that lawmakers might make other major changes, such as scrapping the requirement that all Americans must have health coverage or pay a fine.

Aetna, citing financial risk and the uncertain outlook, said on Thursday it is still evaluating other remaining individual insurance markets, which include Delaware, Nebraska and Virginia. The company exited about a dozen markets this year. In January it said it had more than 240,000 people in such individual plans and expected to post losses on them this year.

Aetna shares were up 0.9 percent at $128.46 on Thursday afternoon.

Evercore ISI analyst Michael Newshel said the move had little impact on its outlook for Aetna’s 2018 earnings forecast given the small number of customers it believes the company has in Iowa.

Aetna is the biggest seller of Obamacare-compliant plans in the state and according to Iowa state insurance data, had more than 30,000 people in such plans in 2016.

Health insurers are preparing 2018 premium rate proposals to submit to federal and state insurance regulators over the next few months. Aetna said it had notified regulators of its plans on Thursday.

Alleigh Marré, spokeswoman for the U.S. Department of Health and Human Services, said by email that “insurers are fleeing because the law is fundamentally flawed. Repealing and replacing Obamacare remains the best option.”

Earlier this week Iowa’s insurance regulator said that Wellmark Blue Cross Blue Shield would not sell Obamacare individual plans next year, affecting 22,000 people.

According to data provided by Iowa, Aetna accounted for most of the plans sold on the federally run HealthCare.gov website in 2016. Wellmark accounted for most of the plans sold in the state that comply with Obamacare but are not sold on HealthCare.gov.

Medica Insurance Company also sells Obamacare-compliant plans throughout the states but is the smallest player.