Shares of banks and lenders sank as Treasurys extended gains after the Fed signaled it would basically freeze current policy.

Fed Chairman Jerome Powell said the central bank was committed "to do whatever we can for as long as it takes" to support the economy following the shock caused by the pandemic. He spoke at a virtual news conference after the Fed's policy meeting.

Officials made one change to their policy stance on Wednesday by announcing they would maintain their recent pace of purchases of Treasury and mortgage securities, effectively ending gradual, weekly reductions. They will buy at least $80 billion in Treasurys and $40 billion in mortgage securities, net of maturing bonds, a month.

Simon Property Group is terminating its $3.6 billion deal to acquire Taubman Centers, saying the rival mall owner didn't respond appropriately to the business challenges caused by the coronavirus pandemic. The deal, announced in February, would have combined two mall landlords as the industry struggles with the decline of traditional retail stores against the rising tide of e-commerce.

Taubman described Simon's attempt to terminate the deal as "without merit" in a statement Wednesday afternoon, adding that it still considers Simon to be bound by the agreement.

Write to Amy Pessetto at amy.pessetto@dowjones.com