Walmart shares have plummeted by 10%, their biggest fall in more than 30 years, due to disappointing online sales.
The retail giant said e-commerce sales growth in the fourth quarter was 23%, down from 50 percent in the third quarter.
Online revenues totalled $11.5bn (£8.2bn) last year, however the lack of sales in the fourth quarter meant the retailer lost money.
Chief executive Doug McMillon said: “We expect eCommerce growth to increase from the fourth quarter level as we enter the new year with about 40 percent growth for the year.”
Last year, total revenue surpassed $500 billion for the first time and increased by $15.1 billion.