President Trump speaks before signing an executive order last month on transparency in health care. (Oliver Contreras for The Washington Post)

The Trump administration proposed a rule Monday that would require hospitals to post online the health-care prices they have negotiated with insurers, about a month after President Trump signed an executive order aiming to give Americans more information about the cost of health services.

Health insurers and providers have fiercely opposed having to publicly reveal their negotiated prices, which they say would stifle competition. Yet the Trump administration has argued that forcing hospitals to post their prices will allow consumers to make more informed choices about where to get care and in turn help lower their health-care costs.

Trump has said he is eager to make health care a central plank of his 2020 reelection bid, as voters consistently cite high costs as one of their top concerns. Trump’s June executive order laid out priorities for the Department of Health and Human Services and other agencies in crafting rules to address secrecy in health-care prices.

The administration has prioritized better protecting patients against massive medical expenses, whether through legislation to address surprise medical bills or by promoting price transparency to help consumers understand what they will pay for care, which hospitals and insurers usually do not reveal until patients receive their medical bills.

“The Trump administration . . . is trying to create a more competitive marketplace where providers are competing for patients on the basis of cost and quality,” Centers for Medicare and Medicaid Services Administrator Seema Verma said on a call with reporters. “This is a direct result of President Trump’s executive order on price transparency.”

Under the proposed rule, which is open for a 60-day comment period, CMS would require hospitals to publicize the amount they charge for a set of “shoppable services,” which the agency defines as services that patients can schedule in advance, such as an MRI or a hip or knee replacement. Hospitals also will have to post the prices they have negotiated with insurers, which are typically far less than the prices that hospitals say they charge. CMS said requiring such information would allow consumers to make “apples-to-apples comparisons” of health-care services and help them better understand how much their care will cost.

Hospitals and insurers have warned that being forced to share the results of secret negotiations would crush competition and drive up prices for consumers.

“Publicly disclosing competitively negotiated, proprietary rates will push prices and premiums higher — not lower — for consumers, patients and taxpayers,” said Matt Eyles, president and chief executive of America’s Health Insurance Plans.

The proposed rule imposes a financial penalty on hospitals — up to $300 per day — that do not comply with the requirement to post their prices.