Businesses with up to 15,000 employees and $5 billion in revenue can apply for financing through the $600 billion Main Street Lending Program.
In the past eight weeks, the Fed has pumped nearly $2.9 trillion into the economy.
The Fed has already taken a range of extraordinary actions to support the economy, including slashing interest rates to near-zero.
The Treasury Department has announced five lending facilities to deploy other portions of the money, but has not invested in them yet.
Powell and Treasury Secretary Steven Mnuchin are scheduled to appear before the Senate Banking, Housing, and Urban Affairs committee
Powell appeared to push back against the possibility of a so-called "V-shaped" rebound, noting it was "unlikely" the U.S. will bounce back to pre-crisis levels by the end of the year.
In a "60 Minutes" interview with Scott Pelley on Sunday, Federal Reserve Chairman Jerome Powell predicted the economy would "decline substantially" in the second quarter, as much as four times compared to the previous year.
Powell has pledged that interest rates will remain at the historically low level until the U.S. weathers the outbreak of the virus.
Avoiding a prolonged recession may require additional policy measures, Powell said.
Fed Chair Powell will deliver a fresh update on the U.S. economy Wednesday.
Most large banks in the nation reported slightly lower common equity tier 1 ratios, a key measure of their financial strength.
Powell is a registered Republican and has sat on the Fed's Board of Governors since 2012.
The balance is roughly $1.6 trillion higher than the peak during the 2008 financial crisis.
The U.S. central bank initially launched the lending program to help get money to small- and medium-sized businesses impacted by the coronavirus pandemic
Powell explains why the "Main Street Lending" program is critical to small businesses.
Policymakers vowed to use their "tools and act as appropriate to support the economy"
The central bank has used its full firepower to insulate the economy from the coronavirus pandemic.
The Fed's policy statement comes out at 2 p.m. Eastern
Powell said policymakers at the U.S. central bank are committed to using the full scope of their vast powers to support the economy.
The central bank on Wednesday released minutes from two emergency meetings, held on March 2 and March 15.