Can anything stop Walmart's rally? Maybe high expectations, some analysts say.

The past three years of higher prices have been great for Walmart Inc. Over that time, Walmart shares WMT have more than doubled in value. As shoppers seek savings wherever they can find them, the retail giant has eaten the lunch of its smaller rivals, threatening to take business from beauty retailers, dollar stores and convenience stores. It has also increasingly drawn wealthier shoppers and begun selling digital ads. ...