Shares of MKS Instruments Inc MKSI have lost more than 17% over the past six months.The company is a market leader in 20 product categories and has a "strong set of tier-1 customers," according to JPMorgan.Analyst Peter Peng initiated coverage of MKS Instruments with an Overweight rating and a price target of $145.The MKS Instruments Thesis: The company is well positioned to benefit from strong wafer fabrication equipment spending in advanced logic, "combined with major technology inflections such as advanc ...