Twenty major corporations, including Verizon VZ , Macy’s M , and American Express AXP have formed a new corporate alliance aimed at restraining the cost of employer-provided health care, according to a report in the Wall Street Journal.

The companies cover roughly 4 million employees all told, and “plan to share information about members’ employee health spending and outcomes, with an eye toward using findings to change how they contract for care,” according to the report.

The companies will initially use the alliance as a way to share information about strategies for containing costs, like which procedures most can be used to treat a condition in the most cost efffective way. But some participants hope that the coalition could evolve into one that uses its collective bargaining power to win cost concessions from healthcare providers.

Kevin Cox, the chief human resources officer at American Express, told the Journal that the alliance came about after they circulated a “call to action” for solving Corporate America’s problem with spiraling healthcare costs. This prompted representatives to gather and discuss potential solutions.