I believe this will be because of an increase of online sales for wall mart faster than amazon. Walmart also has major development in china and is able to profit off of China's growing middle class. Investors also forget to realize that online e-commerce is only 20% of global sales. The remaining 80% is done by traditional brick and mortar stores.
From a Technical standpoint Walmart looks due for a price correction. Walmart is down 34% since its highs on January 30th. With the high speculation on amazon I believe Walmart will continue to correct until it hits a lower Fibonacci level. With high levels of support from 70-80$ I doubt Wall mart will go below these levels. I expect a to form or Walmart to bounce off the Fibonacci level around 75$. I expect Wallmar6t to outperform amazon by 2025 and have a bigger steak in Asian countries and Online retail.