Amex said new account acquisitions for its elite Platinum card doubled since a recent revamp. Amex is seeing strong spending among younger cardholders and has geared some perks toward them. Chase said it had its best year for new account acquisitions on its elite card earlier this week. Not even multi-hundred-dollar fee hikes have stifled the consumer appetite for elite credit cards. American Express executives said that early demand for its revamped Platinum card beat their expectations on Friday ...