BlueCross of Tennessee said it will offer Obamacare plans in Knoxville next year after the city was going to be without any Obamacare insurer.

The insurer's decision comes as the stability of the individual market is being thrown into doubt after insurers in three states said they want to raise prices by double digits next year. The health of Obamacare is also taking center stage in Congress' battle to repeal it, which has moved to the Senate.

Before BlueCross' decision, the Knoxville area was set to lose its only Obamacare insurer for next year after Humana said it would leave.

BlueCross told Tennessee's insurance regulator Tuesday that it will expand into Knoxville even though it has lost $400 million on the exchanges over the past three years. The insurer said its performance in 2017 so far "has improved due to a combination of better claims experience and a more sustainable rate structure based on the medical needs of the members we're serving."

BlueCross raised its premiums 62 percent for this year from 2016 rates.

Even though BlueCross will provide service to Knoxville residents, it has not said how much those plans will cost.

BlueCross said the decision to expand doesn't mean it believes the market will be stable. In fact, the company said it may have to charge higher rates because of "potential negative effects of federal legislative and/or regulatory changes."

The insurer singled out the need for President Trump to decide whether he will continue to give insurers cost-sharing reduction subsidies, which are payments in exchange for lowering co-pays and deductibles for low-income Obamacare customers.

Other potential risks for BlueCross include paying the health insurance tax and removing the individual mandate, which requires people to have insurance or pay a penalty. A bill that passed the House last week repealed the tax and the mandate.

However, the Senate plans to start from scratch on creating its own repeal bill, but could take some ideas from the House legislation, which is called the American Health Care Act.

Trump has said he wants to see what happens with the legislation before making a decision on paying the cost-sharing subsidies, but the subsidies will continue for now.

Insurers are pleading with the Trump administration to give insight into whether the payments will continue next year.

Some states already have shown an early picture of rates in 2018. Maryland and Virginia insurers are seeking increases as high as 50 percent for some plans and Connecticut as much as 30 percent.

The rates are still preliminary and could be lowered after negotiations with state regulators.