In the following video, contributor John Reeves gives investors his weekly wrap-up, and tells us the story behind three stocks that were really hit hard this week. He discusses InvenSense's (NYSE:INVN) nearly 20% fall after an analyst downgrade, part of a continuing trend for the company. He also tells us about Westport Innovations' (NASDAQ:WPRT) 5% fall this week, as the stock for this potentially disruptive natural gas engine company remains volatile on uncertainty about the future of the technology. Then he discusses SandRidge's (NYSE:SD) 9% drop this week, on concerns over both management, and the company's production.

John Reeves has no position in any stocks mentioned. The Motley Fool recommends Westport Innovations. The Motley Fool owns shares of InvenSense and Westport Innovations. The Motley Fool is short InvenSense. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.