Since CEO Doug McMillon took the helm last year, Wal-Mart Stores, Inc. (NYSE: WMT) has undergone a number of surprising changes. Some, such as the decisions to raise wages and to ask chicken suppliers to forgo antibiotic use, mark a decided shift from the company's historical strategy.

With the stock down over 15% year-to-date as guidance has been scaled back, it is fair to question whether Wal-Mart is past its prime. As competition from the likes of Amazon.com and others has increased, here are three ways that the world's largest retailer is revamping itself to grow into the future.