On the back of bad news for one of its rivals, Chinese e-commerce company Alibaba Group Holding (NYSE: BABA) saw a bit of a bull run in its stock. The company's American depositary receipts (ADRs) rose more than 3% in price Wednesday, easily beating the 0.4% advance of the bellwether S&P 500 index.

Sale completed

That rival is JD.com (NASDAQ: JD) , which has lost a major American shareholder. In a regulatory filing, Walmart (NYSE: WMT) effectively revealed that it sold its entire stake in JD.com, putting an end to a nearly decade-long partnership. It did not, however, state exactly how many shares it sold, nor how much it reaped in proceeds.

Financial news agency Bloomberg, citing unidentified "people familiar with the matter," wrote that Walmart's proceeds in the sale were roughly $3.6 billion. The divestment was 144.5 million shares of the Chinese company for $24.95 per share. That price is 11% lower than JD.com's Tuesday closing price. Not surprisingly, its stock fell by approximately that amount the following trading session.

Walmart said in a statement that its move "allows us to focus on our strong China operations for Walmart China and Sam's Club, and deploy capital toward other priorities." It didn't get more specific about its plans in the country.

Stiff competition, despite the sizable market

Competitors like the mighty Alibaba are likely a major reason for Walmart's decision to effectively abandon JD.com. The company has struggled against such titans, even though China is a massive consumer market with an economy that continues to grow -- albeit at relatively sluggish rates.

Before you buy stock in Alibaba Group, consider this: