Costco Quietly Testing New Store Concept for 23 Years

For over 20 years, warehouse club juggernaut Costco Wholesale Corp. has quietly been dabbling in a new market: selling supplies specifically tailored to small businesses. Now, Costco could be looking to move more aggressively with a store format in a bid to head off competition from Wal-Mart's small-business friendly brand Sam's Club, as well as a potentially stronger rival if a merger between Staples and Office Depot wins approval.