Falling margins have PayPal trading on the low end of its valuation since its 2015 IPO.A few short years ago, PayPal (PYPL -5.10%) was a red-hot stock as digital payment trends accelerated during the pandemic's height. Its growth was staggering, hopes were high, and so was the stock's valuation. Things have taken a turn in recent years, and slower growth and falling profit margins weigh on the fintech.The company is transforming under its new CEO and is priced on the lower end of its valuation since it went ...