Walmart's mobile wallet can now be used in all 4,600 of its US stores

Walmart's proprietary mobile payment system Walmart Pay can now be used in all of Walmart's roughly 4,600 stores in the United States, including both its signature Supercenters and grocery-centric Neighborhood Markets, the company announced Wednesday.

The world's largest retailer launched its proprietary mobile wallet last December, and has added approximately 3,500 stores to its Walmart Pay network in the past three weeks, Senior VP of Walmart Services Daniel Eckert told reporters.

"We're building deeper relationships with our customers across our ecosystem and are looking forward to delivering new tools like Walmart Pay that allow them to use the Walmart App as their remote control for a faster, more convenient shopping experience," Eckert said.

Customers will be able to use Walmart Pay from their Walmart smartphone app at every register in every store. The payment system allows users to scan a QR code generated at card readers at checkout, allowing for a quick paperless transaction.

Eckert said that it is too early to reveal data regarding the number of Walmart Pay users, but that the Walmart app has 20 million active users. He said that last week, use of Walmart Pay was up 45% week-over-week and that 88% of customers who have tried Walmart Pay at checkout are repeat users.

At the annual Walmart Shareholders Meeting in June, CEO Doug McMillon said that "We have the opportunity to imagine retail again," and that this would include big investments in its technology. This includes the nationwide rollout of Walmart Pay, which met the company's goal of full availability by the first half of the calendar year, as well as its $49 ShippingPass answer to Amazon Prime, drone tech that will allow for more efficient delivery services, and expansion of its delivery service, which includes a pilot partnership with Uber and Lyft.

Eckert said early data suggests that the mobile wallet has no effect on basket size at checkout, but that the company is considering using customers' shopping habits to suggest "smart list" shopping lists, if the customer chooses to opt in.

When asked about other mobile payment systems like Apple Pay, which cannot be used at Walmart locations, Eckert said that Walmart is in talks with third parties concerning the possibility of future partnerships.