What's happening: Shares of auto-industry supplier BorgWarner (NYSE:BWA) dropped as much as 11% today after the company reported earnings.

Why it's happening: Second-quarter sales fell 7% to $2.03 billion and net income was down 22% to $148.1 million, or $0.65 per share. Adjusting for one-time items, the company earned $0.75 per share, which fell below Wall Street's estimate of $0.82 per share.  

What really threw the market for a loop today was lower earnings guidance for 2015. Management now expects earnings to be between $2.95 and $3.10 per share, down from as high as $3.35 to $3.55 per share early in the year.

Currency is hurting BorgWarner, but the bigger surprise may be lower-than-expected demand in China, one of the industry's growth markets. Management said weak light vehicle production in China was one reason it lowered guidance. It may take time to sort out the macroeconomic environment, and until that happens, there will be uncertainty for BorgWarner's demand, which the market is reacting negatively to today.