Carlyle, a Washington, D.C.-based buyout firm, has been in discussions with other private equity firms about assembling a consortium that would make an offer to acquire HPN, the sources said.
HPN generates annual cash flow of around $600 million, according to the sources.
Merkin grew the Los Angeles-based company into a managed care powerhouse in the Californian market, where it serves nearly 700,000 individuals.
Earlier this month, primary care provider VillageMD, which is backed by Walgreens Boots Alliance Inc (WBA.O), said it would acquire private equity-owned urgent care provider Summit Health in a deal valued at $9 billion.
Amazon agreed in July to buy primary care provider One Medical for $3.49 billion, while CVS inked a deal in September to acquire Signify Health for $8 billion.