Why Baidu, GameStop, and Opko Health Slumped Today

The stock market didn't see much volatility on Friday, with most major benchmarks finishing the session very close to where they had started. Without much in the way of market-moving news on the national or global front, most investors instead paid attention to the cross-currents involved with monthly options expirations.

Some other parts of the financial markets were more interesting, with bond yields easing a bit lower after their big upward push earlier in the week and oil prices taking a break from their recent surge. Yet some individual companies suffered from bad news that sent their shares lower. Baidu (NASDAQ: BIDU), GameStop (NYSE: GME), and Opko Health (NASDAQ: OPK)were among the worst performers on the day. Here's why they did so poorly.