Staples made a $1 billion offer to buy rival Office Depot’s consumer business, the latest in its multiyear attempt to consolidate the office-products space.

USR Parent Inc., the owner of Staples, laid out in a letter its plan to buy the consumer-facing units of ODP Corp., including the Office Depot and OfficeMax retail stores and websites. The cash offer, which isn’t for the entire company, is valued at about $18.27 a share, or about 43% of the 30-day average closing share price as of June 2, Staples said in a statement.

ODP didn’t immediately respond to requests for comment.

A deal, if successful, would bring together two of the biggest names in office supplies at a time when brick-and-mortar retailers are trying to adapt to online trends. Staples had previously tried to buy Office Depot, but the $6.3 billion acquisition was called off in 2016 due to antitrust scrutiny. Sycamore Partners-backed Staples offered again in January, this time for about $2.1 billion.

Staples said it plans to start a tender offer for all of the outstanding common shares of ODP unless its negotiations on an alternative transaction prove fruitful.

ODP, which has so far rejected Staples’ recent advances, said last month it intends to split into two publicly traded companies, retaining its retail consumer and small-business products and services, while separating its Business Solutions Division contract unit and independent regional office-supply distribution operations.