For Medicaid insurers, the looming loss of coverage threatens a financial shock.

An estimated 15 million of the 91 million people with Medicaid—or 16.5%—are expected to lose benefits once states begin scrutinizing enrollment, according to the Health and Human Services Department. About a third of those will turn to the health insurance exchange marketplaces for alternative coverage, and 65% of adults will qualify for job-based health insurance, according to the Urban Institute.

These figures help explain why the health insurance industry group AHIP, the Federation of American Hospitals and other healthcare organizations have partnered to provide assistance and resources to people who will have to switch from Medicaid to another form of health coverage.

Among insurers, Molina Healthcare faces the greatest financial risk because it is the least diversified, said Duane Wright, a senior research analyst at Bloomberg Intelligence. Nearly 78% of the company’s $31.97 billion in revenue last year came from Medicaid.

The company will lose $2 billion once redeterminations are complete, Wright said. Molina gained 750,000 Medicaid members during the pandemic pause, and expects about half of them to be dropped from the rolls, according to an earnings report issued last month.

“We have operational protocols in place with member outreach in the states that allow through text, phone and mail to help members reestablish eligibility,” CEO Joseph Zubretsky said during a call with investors at the time. “If determined that they are ineligible for Medicaid, but eligible for a highly subsidized marketplace product, we will then ‘warm transfer’ them over to our distribution channels for marketplace and capture them.”