President Donald Trump signed an executive order Monday that he said would “fundamentally” change the health care market by requiring hospitals to disclose in an easy-to-read format what patients pay out of pocket for services.

The order, which the Department of Health and Human Services will implement, is designed to improve consumer incentives to shop for care, which would expand the potential benefits of health savings accounts. 

“This is a truly big action,” Trump said in the Grand Foyer of the White House before signing the executive order. “Some people say, bigger than health care itself.” 

The HHS, under the order, also will require hospitals to provide more information to researchers and medical providers as a means to develop ways to cut costs.

“No Americans should be blindsided by bills they never agreed to,” Trump said. 

He said the action was the “opposite of Obamacare” because it expands consumer choice. 

“Lack of price transparency has enriched industry giants greatly,” the president said. “There’s frankly no rhyme or reason for what’s been happening for so many years.”

The order won’t take effect immediately, but commences a rulemaking process that will involve public comment. 

According to the White House, patients face wide variations in prices, often for the same services, due to a lack of transparency.

“Hospitals will be required to publish prices that reflect what people actually pay for services. Prices will come down by numbers that you won’t even believe,” the president said, adding the executive order will benefit “the good doctors, not the bad doctors.”

“Today’s action is not just about lower prices, it’s also about helping Americans find excellent care,” he said. 

Trump said he would still be deciding on what to do about “the remnants of Obamacare,” but again reiterated: “We’re always going to protect people with pre-existing conditions.”