Oil services stocks were out of favour on Thursday afternoon with sector constituents Wood Group and AMEC suffering large falls.Oilfield services firm Wood Group sank after Nomura named it as one of the "top 'reduces' for 2013." The broker said that the stock is trading at a 24% premium to the sector average which is "unwarranted given undifferentiated business model and limited upside to earnings per share." Meanwhile, sector peer AMEC was also a heavy faller today following yesterday's third-quarter trading update, in which it warned of a mining slowdown.The engineering consultancy group, which services the mining, nuclear, power and oil and gas markets, said on Wednesday that is was on track to hit its full-year targets despite ongoing economic uncertainty.The firm said mining activity was slowing, but conventional oil and gas activity remained strong, particularly in the North Sea and Gulf of Mexico. Both Canaccord Genuity and Barclays Capital cut their target prices for the stock today.Top performing sectors so far todayIndustrial Metals & Mining 2,391.34 +2.43%Automobiles & Parts 4,781.34 +0.89%Construction & Materials 3,130.84 +0.87%Fixed Line Telecommunications 2,658.63 +0.39%Insurance (non-life) 1,556.31 +0.26%Bottom performing sectors so far todayOil Equipment, Services & Distribution 23,410.81 -3.19%Industrial Transportation 2,276.55 -1.89%General Retailers 1,912.90 -1.49%Life Insurance 4,808.90 -1.48%Aerospace and Defence 3,710.93 -1.33%BC