The exchange market for buying and selling health insurance has been shaken by the collapse of its former rival, the health care exchanges created by the Affordable Care Act.
The health exchanges are designed to allow consumers to compare various types of insurance products, and some exchanges, like the one operated by UnitedHealth Group Inc. and other large companies, have already fallen short of their goals.
They are now being rolled back by the Trump administration.
As of Monday, there were more than 5,000 participating exchanges, according to the Centers for Medicare and Medicaid Services.
They include the Massachusetts exchange, run by the state-run Massachusetts Health Connector; the Connecticut exchange, operated by the Connecticut Health Connectors; and the Pennsylvania exchange, managed by the Pennsylvania Health Connections.
Some states have already said they will not participate in any exchange created by President Trump, including Maine, Minnesota, New Hampshire, New Mexico, South Dakota and Vermont.
A number of smaller exchanges also are struggling, with a number of states saying they will suspend their operations for several months.
Others have said they are struggling because of the difficulties of getting new patients through the existing systems.
Health insurers have been struggling with how to keep premiums low for customers who sign up for insurance through exchanges created under the Affordable Act.
Insurers have said that their efforts to compete for low-income consumers with lower-income customers is key to their survival.
The exchange markets are designed as a way for consumers to buy coverage without having to go through a government exchange or enroll in the Medicaid expansion.
They offer a way to compare health insurance policies, a way of buying insurance in a single, secure location, and the ability to compare insurance products without having insurance companies choose which policies to offer.
Several insurers have said the challenges of selling plans in these markets are overwhelming.
The Minnesota exchange, for example, said it was overwhelmed by applications for plans last week, but said it has received a record number of applications since the law was passed.
“We’ve had an unprecedented volume of applications, and we have seen an enormous increase in the volume of our applications as of Tuesday morning,” said Lisa R. Linn, a spokeswoman for the Minnesota exchange.
She said the state had to suspend enrollment for three days, as it had planned, because of problems getting new applications.
Linn said that while there are other health care systems that are able to offer exchange plans, they tend to operate on a smaller scale.
And many smaller exchanges, which have struggled to get new applicants, have struggled with enrollment.
One of the reasons that insurers are struggling is that the exchanges are so large, and they cannot be managed by one company or a single entity.
There is no single agency that manages the individual marketplace.
It is run by five state insurance commissioners who are appointed by the governor.
The insurers are not allowed to run their own health care plans.
Insurers have struggled for years with how they should operate the exchanges.
Insuring people who do not have health insurance is not the same as offering them coverage.
The law required insurers to offer plans that covered essential health benefits, including maternity and hospital care.
Insurer executives have said there is a risk that people would get sick and lose coverage if they are not fully covered.
The Congressional Budget Office has said that the law’s requirement that insurers cover essential health coverage will have a negative effect on coverage in the individual market, because it will force them to sell more policies to people who cannot afford them.
The ACA mandated that insurers offer health plans that would cover the basic costs of care, but it also allowed insurers to charge more for more services, including hospital and prescription drugs, and limit some benefits.
Insured people are charged higher premiums for health care because they cannot afford those costs.
Some insurance companies are struggling with the fact that their plans are not available on the exchanges, and many are scrambling to sell plans they cannot sell on the federal marketplace.
Many insurers have also said they have not yet received their applications to participate in the exchanges that are being rolled out by the federal government, even though they have to file an application with the Centers of Medicare and Medicare Services (CMS) for the exchange markets they operate in.
The federal government will accept applications from insurers for the first time from the beginning of April, but will not accept applications until the first week of May.
The CMS will not allow applicants to sell individual policies on the marketplace until the federal exchange is operational.
Insurance companies will be allowed to sell insurance on the exchange until the end of June.
But the federal exchanges are already in trouble.
A number of insurers have announced that they are planning to pull out of the market, citing problems with the federal programs that provide subsidies to people with incomes up to 138 percent of the poverty level.
The subsidies, called cost-sharing reductions, reimburse insurers for some of the costs of covering low- and moderate-income people. Insure