Key TakeawaysUPS shares tumbled Tuesday after the shipping giant reported second-quarter profits plunged over 30% from a year ago and missed analysts' estimates.The company, and its shipping rival FedEx, have seen demand fall amid a pullback from pandemic highs for package deliveries.UPS also narrowed its revenue outlook and lowered its operating margin projections. Shares of United Parcel Service (UPS) tumbled 8% in pre-market trading Tuesday after the shipping giant reported second-quarter earnings that w ...