But beyond that threat, there are some big questions looming over the initiative.

1) What is it?

The venture will be an independent company that “is free from profit-making incentives and constraints.” That sounds liberating, and there is no reason to think it won’t be, but such visionary language would pack a bigger punch if it was accompanied by hard cash. The release did not give details about the initial investment in the venture.

2) How big will it really be?

The effort focuses on the United States employees of JPMorgan Chase, Amazon and Berkshire Hathaway. Together, the companies have nearly one million employees (a portion of those, though, are outside of the United States.) That’s a lot of employees but relatively small when compared with 157 million people who had employer health care plans at the end of 2016, according to the Kaiser Family Foundation. Would the venture be able to scale up? Some experts are skeptical about that. Ben Gomes-Casseres, a professor of international business at Brandeis, wrote: “My bet is that JPMorgan and Amazon’s employees have pretty good health coverage, with plans that rank among the richest that the industry has to offer. If so, will these lead users be anxious to find a more cost-effective model? Will they even be willing to experiment with their coverage? And, beyond that – if they do develop a new approach, will it be helpful to the masses of employees at lesser companies, or, worse, the unemployed and uninsured?”

3) Do these companies bring valuable expertise to providing health care at a lower cost?

It’s not clear how much more expertise Amazon, Berkshire and JPMorgan have than companies that have been operating in health care for decades. Amazon could have gotten into pharmacy services years ago, if it had wanted, which means it might have seen complexities and risks that don’t exist in other sectors. Berkshire brings a strong insurance specialization, but not in providing health insurance directly to the consumer. What is more, Berkshire’s point man in the joint health care effort will be Todd Combs, an investor who does not come from the insurance operations of the company.

4) If the high cost of health care is the main problem, what can this venture do to cut costs?

Much depends on whether the effort can address the main reason that health care spending has gone up in the United States versus other countries. A recent Upshot column showed how much of the rise is a result of more being done for patients during hospital stays and doctor visits, or that they are charged more for those services. One way to assess the brash new initiative from Jeff Bezos, Warren Buffett and Jamie Dimon is whether it does anything to address this dynamic.

— Peter Eavis

‘A hungry tapeworm on the American economy.”

That’s how Warren Buffett referred to the nation’s “ballooning costs of health care” Tuesday.

Mr. Buffett’s Berkshire Hathaway announced it is teaming up with JPMorgan Chase and Amazon to form an independent health care company to serve their employees in the United States.