Nike has suddenly become something few investors ever expected it to be: A high-yield dividend stock. With NKE trading around $36, Nike's $0.41 quarterly dividend translates into an annualized payout of $1.64 and a yield of roughly 4.6% . Nike formally declared its latest $0.41 quarterly dividend on August 6. That puts the yield in territory normally associated with utilities, banks and mature consumer staples—not one of the world's most recognizable athletic brands. It is tempting to look at that 4.6% yield and see opportunity. I see something more complicated. Nike's dividend yield hasn't surged because management suddenly became extraordinarily generous. The yield surged because the stock collapsed. And when a dividend yield rises because the denominator is falling rather than because the numerator is rapidly growing, investors need to ask a much more important question: Can the business comfortably afford the dividend? For Nike, the latest numbers provide reasons fo...