What Is a Health Insurance Exchange?

Your state's health insurance exchange makes it easy to comparsion shop for coverage
Your state's health insurance exchange makes it easy to comparsion shop for your coverage.


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A health insurance exchange, otherwise known as a health insurance marketplace, is a comparison-shopping area for health insurance. Private health insurance companies list their health plans with the exchange, and people comparison shop on the exchange from among the available health plan listings.

The phrase health insurance exchange most commonly refers to public health insurance exchanges developed by the government because of the Affordable Care Act (the ACA, also known as Obamacare) although private health insurance exchanges do exist. Private health insurance exchanges are usually designed to serve several large employers, so most people will only encounter them when signing up for job-based health insurance.

Public health insurance exchanges are used to buy individual and family health insurance plans that are compliant with the ACA. Small group plans are also available in the public exchanges, although virtually all of the enrollment has been individual market coverage ("individual market" means health insurance that people buy on their own, as opposed to coverage that's obtained through an employer or via a government-run program like Medicare or Medicaid). And people who are eligible for Medicaid based on their income can enroll in Medicaid via the exchange in their state.

But this article focuses on the ACA's public health insurance exchanges, and the individual market health insurance plans that make up the bulk of the exchanges' private plan enrollments. It's "exchanges," plural, because each state has an exchange. And although the word marketplace invokes the mental image of a physical place where shoppers wander from stall to stall checking out the vendors' wares, most people access health insurance exchanges via the internet. The largest health insurance exchange, HealthCare.gov, is run by the federal government, serving health insurance shoppers in 39 states. The other 11 states and the District of Columbia each run their own exchanges.

What's the Difference Between "On-Exchange" and "Off-Exchange"?

If you're buying a health insurance plan in the individual market, you'll probably hear people referring to "on-exchange" plans versus "off-exchange" plans. An "on-exchange" plan is simply one that's purchased through the exchange. People can shop for exchange plans on their own, or they can have help from a broker or navigator (and in some cases, "on-exchange" plans can be purchased via an online broker's website; ask plenty of questions if you're working with a broker or a private website, to ensure that you're getting an on-exchange plan if that's your preference).

"Off-exchange" plans, on the other hand, are purchased without going through the ACA exchange in your state. They can be purchased directly from an insurance company, or with the help of a broker. Premium subsidies and cost-sharing subsidies are not available if you buy an off-exchange plan, even if you'd otherwise be eligible (and you can't go back and claim the premium subsidy on your tax return if you bought an off-exchange plan).

But in many cases, the plans themselves are identical or nearly indentical, on- and off-exchange. All individual major medical plans with effective dates of January 2014 or later are required to be fully compliant with the ACA, regardless of whether they're sold in the exchange or off-exchange. That part is important: Insurance companies cannot sell non-compliant health plans in the individual market, even if they sell them outside the exchange.

Depending on how your state has structured its exchange, the health plans available on-exchange might have to adhere to additional requirements beyond simply being ACA-compliant.

Some insurers choose to only offer their plans for sale on-exchange, others only offer them off-exchange, and others offer plans both on- and off-exchange (note that Washington DC does not allow plans to be sold off-exchange; ACA-compliant individual and small group health plans can only be purchased there via DC Health Link, the District's health insurance exchange).

Plans that are currently for sale but not compliant with the ACA have to fall into the category of "excepted benefits," which means they're specifically exempt from the ACA's rules, and are, by definition, not individual major medical health insurance. Excepted benefits include short-term health insurance, limited benefit plans, fixed indemnity plans, accident supplements, critical illness/specific disease plans, and dental/vision insurance. With the exception of short-term plans to fill a temporary gap in covreage, none of the excepted benefits are designed to provide stand-alone medical coverage; they're all designed to serve as supplemental coverage. Excepted benefits are available off-exchange in most areas (and dental/vision plans are available on-exchange in many areas).

How Many People Have Coverage Through the ACA's Exchanges? 

At the end of open enrollment for 2018 coverage (which ended on December 15, 2017, in most states), total exchange enrollment in individual market plans stood at 11.8 million people, including enrollments conducted via HealthCare.gov and the 12 state-run exchanges.

As of February 2018, effectuated enrollment (ie, in-force policies for which the premiums had been paid) stood at about 10.6 million people. Effectuated enrollment is always lower than the number of people who sign up during open enrollment, as there are invariably some people who don't pay their initial premiums or who cancel their coverage shortly after enrolling.

Small businesses can enroll in plans through the exchanges, but there were fewer than 200,000 people enrolled in small business exchange plans nationwide in 2017—the vast majority of the ACA exchange enrollees have coverage in the individual market. 

How Health Insurance Exchanges Work

Exchanges are designed to increase competition and ease comparison shopping. Insurance companies compete for your business in the exchange. This direct competition is meant to keep the cost of health insurance premiums down. Exchanges/marketplaces ease the comparison of plans by using an "apples to apples" approach:

  • All health insurance policies offered through the exchanges provide a minimum set of essential health benefits. This is part of being ACA-compliant, so the off-exchange individual major medical plans available in your area will also cover the essential health benefits:
  • All health insurance policies offered must conform to one of five benefit tiers: catastrophic, bronze, silver, gold, or platinum.
  • Standardized plans are available in the exchanges in some states. In California's exchange, all of the plan are standardized.

    Both on- and off-exchange, a policy’s benefit tier (bronze, silver, gold, or platinum) describes the percentage of covered health care expenses the plan will pay, otherwise known as the actuarial value (AV) of the plan. You can learn more about how these benefit tiers work in, " Bronze, Silver, Gold, and Platinum—Understanding the Metal-tier System." In most areas of the country, platinum plans are scarce or not available at all. Silver and gold plans are available in all areas of the country (insurers that offer plans in the exchange are required to offer them at at least the silver and gold level) and nearly every county in the US has bronze plans available.

    Exchanges provide subsidies to help pay for health insurance. Health insurance exchanges are the only access point for government subsidies (premium tax credits) that make health insurance more affordable for Americans with modest incomes. You can apply for a government health insurance subsidy through your health insurance exchange, and the subsidy is only good for health insurance bought on the health insurance exchange. Learn more about health insurance subsidies in, "Can I Get Help Paying for Health Insurance?"

    Even if you think you might be eligible for a premium subsidy, but aren't sure due to fluctuations in your income, you'll want to consider buying a plan through the exchange. You can pay full price and then go back later and claim the subsidy (since it's really just a tax credit) on your tax return. But you can't do that if you bought your plan off-exchange.

    There's a new twist, however, that started to apply in 2018: People who aren't eligible for a premium subsidy and who want to purchase a silver-level plan may find that the off-exchange versions of the plans are less expensive. That's because of the way the cost of cost-sharing subsidies are being added to the premiums. But bear in mind that you can't switch back to an on-exchange plan mid-year if your income drops and makes you subsidy-eligible (unless you have a qualifying event; a change in income isn't a qualifying event unless you're already enrolled in an on-exchange plan).

    In addition to premium subsidies, cost-sharing subsidies (also known as cost-sharing reductions) are also only available if you buy a silver plan through the exchange in your state. If your income makes you eligible for cost-sharing subsidies and/or premium subsidies, you'll want to enroll through the exchanges (as opposed to enrolling off-exchange an insurance company) in order to take advantage of the available assistance.

    Finding Your Health Insurance Exchange

    Your state may run its own health insurance exchange such as the one run by California, Covered California. Or, your state may have opted not to create a health insurance exchange, or to create an exchange but use the federal enrollment platform. In that case, residents use the federal government's exchange at HealthCare.gov. Find out how to contact the health insurance exchange in your state, or whether residents of your state use the federal government's exchange.

    The following states have their own enrollment websites, although you can get to them by starting at HealthCare.gov and clicking on your state or entering your zip code:

    In every state, enrollment in the exchange (and outside the exchange, for individual market coverage in every state except Nevada) is limited to annual open enrollment windows and special enrollment periods triggered by qualifying events. Open enrollment for 2019 coverage will run from November 1, 2018 to December 15, 2018 in every state that uses HealthCare.gov, as well as several of the states that run their own exchanges.

    But there are some exceptions, as states that run their own exchanges can extend the length of open enrollment. The enrollment window will be longer for 2019 coverage in California, Colorado, DC, Massachusetts, Minnesota, and Rhode Island.

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