Sina (SINA) owns one of the most visited portals in China. It reported good earnings for the last quarter, up 40 percent. But its forecast was troubling. According to The Wall Street Journal, "the owner of China's largest Web portal issued a weak first-quarter revenue outlook as the economy hit advertisers."

That news is bad for two reasons. The first is that it could push the company's share price down. At less than $21 it is already near a 52-week low, down from a period high of $58.60.