"Staples, which is owned by the private-equity firm Sycamore Partners, will establish a firewall separating Staples' business-to-business sales operations from Essendant's wholesale business," the regulator said in a statement.

"This firewall will restrict Staples' access to the commercially sensitive information of Essendant's customers."

(Reporting by Eric Beech; Writing by Mohammad Zargham; Editing by Sandra Maler)