Medicare Advantage is growing, again

Almost 22.4 million seniors and people with disabilities are enrolled in Medicare Advantage plans for 2019 — up 6.8% from the same point last year, according to preliminary federal data.

Why it matters: The growing enrollment total is in line with what the Trump administration expected and continues a decade-long trend of moving more of the traditional Medicare program into a privatized version run by health insurers.

Winners: Most insurers are winners to some degree, considering MA is "a friendly environment" right now for the industry. And the biggest companies are getting even bigger.

By the numbers: Together, three companies control more than half of the MA market.

• UnitedHealth Group: 5.7 million enrollees, up 9%
• Humana: 3.9 million, up 11%
• Aetna (now owned by CVS Health): 2.1 million, up 23%

The big picture: The federal government is expected to pay MA insurers $250 billion this year. With profit margins hovering around 4% or higher for many companies, that equals billions of dollars of profit.

Yes, but: Federal prosecutors and auditors are scrutinizing the coding practices of MA insurers and may be willing to claw back overpayments soon.

• Many enrollees also may be unaware of the program's shortcomings.

What's next: February's enrollment data will provide an even clearer picture of how much the Medicare Advantage program grew for this year.