Shares of Vipshop (NYSE: VIPS) tumbled nearly 20% on May 15 after the Chinese e-tailer reported its first-quarter numbers. Its revenue rose 25% annually to 19.9 billion yuan ($3.2 billion), beating estimates by $120 million, but its non-GAAP net income dropped 9% to 728 million yuan ($116 million), or 1.05 yuan ($0.17) per ADS, missing expectations by a penny.