** Shares of American Express AXP.N rise ~2% to $352.50 in premarket trading

** J.P. Morgan upgrades stock rating to "overweight" from "neutral" and hikes PT to $400 from $328, representing a 14% upside to the stock's last close of $350.58

** Brokerage says AXP's affluent customer base is relatively shielded from the energy squeeze and offers defensive revenue visibility in an uncertain backdrop

** "AXP's affluent customer base is likely to maintain spending levels unless a new tail risk emerges that drives up unemployment" - JPM

** 12 of 31 brokerages rate the stock "buy" or higher, 19 "hold"; their median PT is $367 - LSEG-compiled data

** As of last close, stock down 5.2% YTD