Humana

Humana Inc. concentrates on Medicare Advantage, the private version of Medicare. In many US counties only a handful of insurers bid for those members. Humana is often one of the two largest.

The Justice Department and states sued to block Aetna's acquisition of Humana. A federal judge enjoined it in 2017 and the deal died. The opinion treated Medicare Advantage as its own market. That case is why a Humana combination with another large MA insurer is presumed hard.

Humana has integrated downward into primary-care clinics. An insurer that employs the doctors who steer referrals and document risk scores has a vertical advantage over a clinic that bills the same insurer at arm's length. The theory is foreclosure and data, not a classic price fix.

Risk-adjustment coding in Medicare Advantage pays more for sicker recorded members. When the insurer owns the clinic, the documentation and the payment sit in one company. That is a competition and a fraud-enforcement overlap.

The 2017 Aetna-Humana injunction is the merger boundary for Medicare Advantage.

County-level MA markets are concentrated even when national share looks moderate.

Clinic acquisitions can steer patients and records toward the owner's plan.

Exclusive provider networks in MA plans limit which hospitals remain in the choice set.

A retiree picking a plan in a two-insurer county is not in a competitive market, even if the brochure says otherwise.

Independent clinics negotiating with Humana lose leverage if Humana employs the rival clinic down the road.