Anthem Inc.’s decision to quit Ohio’s Obamacare market willleave 13,000 people without any coverage option under the programnext year. That number may rise to 300,000 if the health insurerfollows suit in the rest of the states where it sells.

Related: Cuomo takes steps to keep New York insurers inObamacare

Anthem, which currently oversees Affordable Care Act plans forabout 1.1 million people in 14 states, is one of the largest of themultistate insurers that hasn’t pulled back sharply from sellingindividual plans in the ACA.

In April, it said it was “ assessing our market footprint in2018,” and on Tuesday the company said it would leave Ohio.

Insurers are increasingly stepping away from the law amidfinancial losses on their plans, Republican threats to repeal largesections of it, and President Donald Trump’s administration’sefforts to undermine parts of the program.

Trump has called the program a failure and has backed efforts toreplace it, though provided few details on how.

Related: Aetna to quit Virginia's ACA market as CEO limitsrisk

Currently, there are more than 30,000 people with Obamacareplans who are projected not to have an insurer under the programnext year, according to data compiled by Bloomberg. An Anthem exitwould raise that number to 300,000 people in seven states.

The numbers could change as more insurers decide to join orleave the program, and states are still hearing from insurers abouttheir intentions. Bloomberg’s analysis includes exits by otherinsurers.

About 12.2 million people bought insurance plans on Obamacare’sexchanges for this year, with 10.1 million of them receivinggovernment subsidies to help them afford the insurance, accordingto a U.S. government report. The health law’s subsidies are onlyavailable for insurance plans sold in Obamacare’s markets.

Related: 5 areas likely to lose ACA insurers

Congress, Trump

The loss of another insurer in the program would put morepressure on Republicans in Congress who are attempting to repealand replace large parts of Obamacare, which they also call afailure. Repealing the law -- a key GOP campaign promise -- hasproven harder than expected as lawmakers haven’t been able to reachconsensus on what a revamped system would look like, or how tocover millions of Americans who are insured under the program.

In a visit to Ohio Wednesday, Trump called again for Congress tomove quickly ahead with its Obamacare replacement bill, which iscurrently being revised by the Senate after being passed by theHouse.

“The Republicans are trying very hard,” to get a bill passed,Trump said, “and the Democrats are in our way.” Ohio is the homestate of Republican Senator Rob Portman, who’s said he supportshealth-care reform but not the House bill.

In the meantime, management of Obamacare has been left in limbo.The administration has threatened to stop paying subsidies toinsurers that help some lower-income people use their insuranceplans. That threat has caused insurers to say they’ll raise ratesfor next year, or leave some markets entirely.

Anthem’s view

“Planning and pricing for ACA-compliant health plans has becomeincreasingly difficult due to the shrinking individual market aswell as continual changes in federal operations, rules andguidance,” Anthem said of its exit from Ohio. “The lack ofcertainty of funding for cost sharing reduction subsidies, therestoration of taxes on fully insured coverage and, an increasinglack of overall predictability simply does not provide asustainable path forward to provide affordable plan choices forconsumers.”

Anthem’s Ohio exit will leave 20 counties in the state withoutan Affordable Care Act coverage option in 2018.

Blue Cross Blue Shield of Kansas City said last month it willpull out of the exchange in Missouri, leaving 25 bare counties andabout 18,500 people without an ACA coverage option. Humana Inc.said earlier this year it would pull out from all 11 states nextyear where it currently sells ACA plans. Aetna Inc. said in May itwould do the same, also announcing plans to abandon the fewremaining states where it had been selling ACA coverage.UnitedHealth Group Inc., the largest U.S. insurer, has alreadyexited ACA exchanges in most of the states where it sold plans.Some small and regional insurers have pulled out of states orcounties as well.

If Anthem decided to leave the exchanges nationwide, another 310counties could be without ACA plans in Colorado, Georgia, Kentucky,Missouri, Nevada and Virginia in addition to Ohio, bringing thetotal number of bare counties to 355. Anthem did file a raterequest in Virginia for next year but could still decide not tosell there.

“This is just more evidence that conditions under Obamacare arejust going to get worse. It is collapsing under its own weight,”Representative Pat Tiberi, an Ohio Republican, said Tuesday in astatement.

The U.S. House last month passed the American Health Care Act torepeal and replace parts of Obamacare. Now, the Senate is workingon its own version of the legislation. Senate Majority Leader MitchMcConnell said Tuesday the chamber is “ closer to having a proposalthat we’ll bring up in the near future.”

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