Shares of Dollar Tree Inc (NASDAQ:DLTR) are 2.8% higher premarket following a bull note from J.P. Morgan Securities. The analyst upgraded the discount retail stock to "overweight" from "neutral" and raised its price target from $122 to $157 -- an 18.3% upside to Friday's close.The Wall Street brokerage cited higher profitability, calling the company's Family Dollar banner store's optimization a potential "win-win" catalyst. What's more, Dollar Tree's CEO said deflation could present a multi-year merchandisi ...