Amazon, Berkshire Hathaway and JPMorgan Chase announced today that they are partnering on ways to address healthcare for their U.S. employees, with the aim of improving employee satisfaction and reducing costs.

News Tuesday that the three companies plan to join forces to change how health care is provided to their combined 1 million U.S. employees sent shock waves through the health-care industry. The plan, while focused solely on the three giants’ staff for now, seems almost certain to set its sights on disrupting the broader industry.

Amazon, Berkshire and JPMorgan are among the largest private employers in the U.S. And they’re among the most valuable, with a combined market capitalization of $1.6 trillion, according to data compiled by Bloomberg.

It’s the first big move by Amazon in the sector after months of speculation that the internet behemoth might make an entry. The Amazon-Berkshire-JPMorgan collaboration will likely pressure profits for middlemen in the health-care supply chain.

The announcement was enough to sink health-care stocks. Express Scripts Holding Co. and CVS Health Corp., which manage pharmacy benefits, slumped 6.9 percent and 4.9 percent, respectively. Health insurers such as Cigna Corp. and Anthem Inc. and biotechnology companies also dropped.

The three companies, which bring their scale and complementary expertise to this long-term effort, will pursue this objective through an independent company that is free from profit-making incentives and constraints.

The initial focus of the new company will be on technology solutions that will provide U.S. employees and their families with simplified, high-quality and transparent healthcare at a reasonable cost.

The group plans to hire a CEO and start partnering with other organizations, according to a person familiar with the matter. The effort would be focused internally first, and the companies would bring their data and bargaining power to bear on lowering health-care costs, the person said. Potential ways to bring down costs include providing more transparency over the prices for doctor visits and lab tests, as well as by enabling direct purchasing of some medical items, the person said.

The the company jointly will be spearheaded by Todd Combs, an investment officer of Berkshire Hathaway; Marvelle Sullivan Berchtold, a Managing Director of JPMorgan Chase; and Beth Galetti, a Senior Vice President at Amazon.

The longer-term management team, headquarters location and key operational details will be communicated in due course.