Health insurance companies know that an insurance market without the requirement that everyone get coverage will be worse for them and their customers. They just arent sure how much worse.

HuffPost contacted dozens of health insurance companies to ask them to assess the impact that removing the so-called individual mandate which Republicans in Congress are on the verge of doing as part of their tax bill would have on their businesses and their customers.

Fifteen companies responded and all warned that eliminating the mandate would force them to further raise prices, and could drive some insurers to leave the market altogether. Both of those outcomes would lead to fewer Americans having health insurance and destabilize an insurance market already plagued with problems.

Lets assume for a second that you eliminate the mandate and so those healthy people decide to sit out, whether they need a subsidy or not, the pool shrinks, said Jim Havens, senior vice president of individual and senior markets for Mountlake Terrace, Washington-based Premera Blue Cross.

That means that the people left are people who either intend to use it or think they will be using it, which is going to make it more expensive, Havens said. Premera is the sole insurer offering individual policies in Alaska and also operates in Washington state.

The biggest losers would be middle-class people who dont get health benefits from their employers and make too much money to receive subsidies for private insurance from a health insurance exchange. They will see fewer choices and higher prices in the future.

People who live in sparsely populated regions are at the greatest risk of extremely high premiums, and of having no insurers doing business where they live because rural areas already are the toughest locations to make a profit.

The Senate approved a massive tax bill earlier this month that would eliminate the Affordable Care Acts tax penalties for those who dont adhere to the mandate to have health coverage, and the House likely will go along if Republicans are able to come to a final agreement on a tax package they can send to President Donald Trump for his signature.

State officials along with health care industry groups representing insurers, doctors, hospitals and more oppose repealing the mandate , which is a key tool the Affordable Care Act uses to compel healthy people to enroll in health insurance. Thats because the premiums of the currently healthy are key to financing the medical claims of the currently unhealthy.

Thats crucial because the law allows all people access to health insurance, regardless of pre-existing conditions or health needs, and all evidence indicates people who need medical care are taking advantage of it.

The requirement that people have coverage year-round is critical. Those who buy coverage only when they need it then drop it later drive up costs for everyone, Daniel Hilferty, CEO of Philadelphia-based Independence Health Group, said in a written statement. His companys Independence Blue Cross is the only individual insurance provided in Philadelphia and its Pennsylvania suburbs, and its AmeriHealth New Jersey unit sells policies in the Garden State.