The U.S. Department of Health and Human Services on Thursday trotted out insurance executives who have found success selling health plans to individuals via the online insurance exchanges, a key part of the Affordable Care Act.

The conference, held in Washington and live-streamed to journalists and others, gave industry executives an opportunity to outline their strategies and challenges at a time when some major insurers are questioning the viability of plans sold on HealthCare.gov and the state-run exchanges.

In April, UnitedHealth Group Inc. announced it would stop offering exchange plans in many states next year, including Missouri and Illinois. The nation’s largest health insurer said it couldn’t make money on plans because of lower-than-expected enrollment and sicker people buying its plans.

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