Weil Gotshal & Manges, Wilmer Cutler Pickering Hale and Dorr, Simpson Thacher & Bartlett and Clifford Chance (CC) have all secured roles on Staples' $6.3bn (£4bn) acquisition of rival Office Depot.

The deal will face the scrutiny of US competition regulators as it would create the largest office supply superstore chain in America.

Weil is acting for Staples on antitrust and shareholder matters, with a team led by New York corporate partner Michael Aiello and Washington DC-based antitrust partners Steven Newborn and Steven Bernstein.

Wilmer Hale is advising the buyer on the corporate aspects of the transaction, with a team headed by Boston partner Mark Borden. Barclays is acting as exclusive financial adviser to Staples.

Staples has turned to CC for advice on EU antitrust matters, which is fielding a team led by Brussels partner Tony Reeves.

Simpson Thacher is advising Office Depot on the buyout with a team headed by M&A partner Mario Ponce, antitrust head Kevin Arquit and antitrust partner Matt Reilly.

Partners from the firm are also advising on the intellectual property, tax and employment aspects of the deal.

Peter J. Solomon Company is acting as the sole financial adviser to Office Depot.

Staples' chairman and chief executive officer, Ron Sargent, said: "This is a transformational acquisition that enables Staples to provide more value to customers, and more effectively compete in a rapidly evolving competitive environment."

The deal is still subject to regulatory and shareholder approval and is expected to close by the end of the calendar year 2015.