BlackRock co-founder and CEO Larry Fink said Thursday the U.S. needs to increase its testing capacity for the coronavirus before its economy can restart in earnest. 

“We’re going to still see elements of the disease increasing in other parts of the world and until we have adequate testing, rapid testing, it’s very hard to see how we’re going to reboot in the next 30 days,” Fink said on CNBC’s “Squawk Box.”

Fink expressed confidence that the U.S. will make progress on Covid-19 treatments, minimizing the severity of the disease. “Through that process, I do believe we’ll be able to reboot. I do believe we’re going to have a better, more normalized environment,” he said. 

“But it may not be in June or July. It may be in August,” he said.

Fink, whose firm is the world’s biggest asset manager, said he believes businesses will be “very cautious” and “protective of their employees” as they consider when and how to relax work-from-home policies. 

“They want to make sure their employees feel good about coming back to the office,” he said. “Let’s be clear: anxiety is still very high.”

Jeff Bezos, in Amazon‘s annual shareholder letter published Thursday, echoed Fink’s position that widespread testing is needed to make companies feel comfortable getting back in their offices.

“Regular testing on a global scale, across all industries, would both help keep people safe and help get the economy back up and running,” Bezos wrote. “For this to work, we as a society would need vastly more testing capacity than is currently available.”

There are signs that daily increases in new Covid-19 cases in the U.S. may be slowing, causing the national debate to begin focusing on how the U.S. will reopen the economy.

President Donald Trump recently announced a new group — made up of business leaders from all manner of industries — aimed at focusing on how to reboot business. Trump had a call with many of those executives Wednesday, according to the Washington Post. 

Fink said he of course wants the U.S. to “have the ability to reboot,” but he repeated his current concerns about testing. ”I know many leaders told the president yesterday, we need to have adequate to make sure we have a secured environment.”

Trump has said he thinks some states may be able to relax restrictions by the end of April.

In Thursday’s interview on CNBC, Fink also said that the stock market’s coronavirus low last month may have been the pandemic bottom.

“If the disease curve in the developed world continues to decline [and] at the same time we see the curve from governmental support for monetary policy and fiscal policy worldwide increases, we could have seen the bottom,” said the BlackRock chairman and CEO.