The U.S. economy will “improve dramatically” in the second half of the year, Treasury Secretary Steven Mnuchin is expected to tell the Senate Committee on Small Business and Entrepreneurship on Wednesday.

"America's economy has begun to rebound, and our recovery is underway," read Mnuchin's written testimony.

Mnuchin, along with Jovita Carranza, the Administrator of the Small Business Administration, will be taking questions about the rollout and efficiency of the $660 billion Payroll Protection Program (PPP) amid the coronavirus pandemic. The PPP offers financial aid to small businesses impacted by the virus, but the program had a messy start when it launched in early April.

“As you might expect with a program of this magnitude executed on a national scale in record time, we initially experienced some complications. We resolved them quickly,” Mnuchin said.

Mnuchin claimed the PPP is employing roughly 50 million workers and subsidizing the payrolls of more than 75% of small businesses across the country.

The PPP was criticized after large businesses such as restaurant chains Shake Shack and Potbelly Sandwich Shop took out loans from the program. Both Shake Shack and Potbelly Sandwich Shop have returned their PPP funds.

Bank of America, one of the creditors working with the PPP, has been slammed for prioritizing larger loan amounts in order to generate more origination fees. Bank of America, along with Wells Fargo, JPMorgan Chase and US Bank were sued over the issue.

Each bank "concealed from the public that it was reshuffling the PPP applications it received and prioritizing the applications that would make the bank the most money," the lawsuits say.

Despite these controversies, the PPP could be playing a critical role in helping the economy recover. On Friday, a report from the Bureau of Labor Statistics revealed that 2.5 million jobs were added in May, unexpectedly beating estimates from economists of 7.5 million job losses during the month.

In the first quarter of the year, the economy declined by 4.8% as the coronavirus slammed businesses across the country. In the second quarter, this number could be as much as a 53% drop, according to the Atlanta Fed.

The U.S. currently has the highest number of coronavirus cases in the world. As of Wednesday at 11:55 a.m. ET, there are nearly 2 million coronavirus cases and over 112,000 deaths in the U.S.