The delivery giant's dividend looks sustainable, but there is little room for significant improvement in the coming years. Investors attracted to UPS (UPS 1.43%) stock are, no doubt, drawn at least in part by its generous 4.7% dividend yield. But how sustainable is that payout, and what are the prospects that the company will continue its 15-year run of raising its dividend per share next year? Here's the lowdown. UPS' dividend payout Usually, when investors discuss a payout ratio, they compare dividends pe ...