NCR Corp.'s shares closed 3.97% higher on May 21 following reports that the ATM manufacturer is working with Bank of America Equities on a possible company sale.

According to Deal Reporter, sources said Warburg Pincus LLC and NCR have been in discussions about a transaction in recent weeks, Finextra reported.

Apollo Global Management LLC and other private equity firms are also rumored to be on the hunt, Finextra reported.