Dive Brief:

• Rival warehouse retailers Costco and Sam's Club each separately announced express delivery of certain products for businesses, according to TheStreet.
• Costco Business Center in San Diego will start offering a two-hour grocery delivery service via a partnership with delivery firm Instacart, and has plans to eventually expand the service to include office supplies. 
• Wal-Mart-owned Sam's Club is offering next-day delivery of office supplies in the Dallas, Tulsa and Miami markets. In Miami, it's using Deliv to handle small orders and Need It Now to carry larger orders, such as office equipment. In Dallas, Wal-Mart is using its own trucks to deliver orders. 

Dive Insight:

These new express delivery services from two major retailers are intriguing on at least a couple of levels. For starters, both Costco and Wal-Mart are taking competitive aim at Staples and Office Depot — the walking wounded of the retail office supplies market. Both of those companies are still reeling from having their planned merger squashed in court.

Neither Staples nor Office Depot was doing well before the merger was canceled, and though both have been trying to cultivate rebound plans with their own new services and promotions, they certainly are weakened an susceptible to competitors wooing away their regular customers with something like a new express delivery service.

Both new services from Costco and Sam's Club also represent potentially valuable partnerships for delivery companies Instacart, Deliv and Need It Now. All are part of a big wave of entrepreneurial effort and rapid expansion that has come to characterize the delivery space in the last few years.

While Instacart has grown rapidly, it also has fussed over its delivery model, making frequent adjustments. Deliv, meanwhile, earned an investment from shipping sector stalwart UPS earlier this year, and has become something of a lab rat for the larger company as UPS studies the impact of new shipping and delivery schemes on its market.

A third area of intrigue is how both Costco and Wal-Mart are looking to lure more business customers at a time when both brick-and-mortar stores are dealing with increasing pressure from online competition over their core consumer customer bases, and looking for new revenue sources. As it turns out, they are both following Amazon further into the space, as the e-commerce giant also courts businesses via its own Amazon Business and B2B marketplace efforts. The new delivery services may be a method for Costco and Wal-Mart to take the competitive fight to Amazon's virtual doorstep in a new market.

For now, these efforts by Costco and Sam's Club are very limited in scope, but both will be interesting to watch for their impact on the retail office supplies segment, the delivery startup ecosystem and for both retailers' ongoing competitive dynamics regarding Amazon.