Videos This week, Kevin Matras shows how to use the Price to Sales ratio. Highlighted stocks include GPRE, KIRK, SPR, TOWR and VVTV. Articles You May Like Why Silver ETFs are Outshining Gold Is There a Deal in Groupon’s Stock? Four Factors Behind the Zacks Rank Performance 443 TIP. Buffett’s Biggest Blunders w/ David Kass iRobot (IRBT) and Michael Kors (KORS): Bull & Bear of the Day