On Wednesday during the company’s annual investor meeting, Wal-Mart Stores, Inc. (NYSE:WMT) is expected to announce details for the expansion of its small “Express” stores, reported the Associated Press.

According to Citi Investment Research analyst Deborah Weinswig, through the end of July, Wal-Mart Stores, Inc. (NYSE:WMT) had 10 “Express” stores. These venues are one-tenth the size of Wal-Mart Supercenters, and include groceries and general merchandise, such as tools and pharmacies.

Wal-Mart logo

Wal-Mart Stores, Inc. (NYSE:WMT) also has 217 Neighborhood Markets, which are greater than twice the size of Express stores. They offer perishable food, household supplies, beauty aids, and also pharmacies.

This is just the beginning for the company’s smaller-size stores, as it may expand its role inside city centers, added Weinswig.

A current snapshot of  Wal-Mart Stores, Inc. (NYSE:WMT), in cities where the company has a lower than 20 percent market share in supermarkets, paints an interesting picture. Jefferies analyst Scott Mushkin suggested that by moving into cities, such as San Diego, San Francisco, Boston, Los Angeles, Miami, and New York, along with smaller ones, it could “potentially pose significant challenges for Safeway, Supervalu, Ahold, and Roundy’s.”

As for the large supermarket chains, their tentacles are wide-reaching, and could be impacted by these smaller Wal-Mart stores. Supervalu’s chains include Albertsons, Cub Foods, and Jewel-Osco. As for Safeway, it has its name stores along with Dominicks and Vons. Roundy’s manages Pick n Saves and Rainbow chains–to name a few. Netherlands-based Ahold is the owner of the U.S. Stop & Shops and Giant Food grocery chain stores.

With Wal-Mart Stores, Inc. (NYSE:WMT) tapping into these markets, it could result in pricing pressures, and taking customers away from these established venues.

From the impending news of Wal-Mart’s growing reach, Supervalu Inc. (NYSE:SVU) shares were down 0.90 percent to $2.20. Safeway’s (NYSE:SWY) shares increased 1.18 percent to $16.35, while Roundy’s Inc (NYSE:RNDY) shares dropped 2.70 percent to $6.12.

In other Wal-Mart Stores, Inc. (NYSE:WMT) news, at the start of this new week, the retail giant announced plans with American Express Company (NYSE:AXP) to partner and offer Bluebird, an alternative debit account, including mobile banking features.

The companies explained that Bluebird is a prepaid debit card that will help customers manage and easily control daily finances, with advanced features including the use of smartphones, mobile payments, and fee transparency. The card will not require a minimum balance, monthly or annual fees, and it comes without overdraft fees.

It will also enable consumers to deposit money directly from employers and remote check capture. They can also utilize it as cash at any Wal-Mart Stores, Inc. (NYSE:WMT) register, or by linking the card to a checking, savings, or debit card.

Interested consumers can sign up for Bluebird, beginning next week.

On Monday, Wal-Mart closed up 0.16 percent to $75.25.