A very large part of this is simply that Nike was trading at an extremely aggressive valuation a few years ago. The business is obviously struggling and while

A very large part of this is simply that Nike was trading at an extremely aggressive valuation a few years ago. The business is obviously struggling and while some of the decline is related directly to that, the stock collapse mostly attributable to investors rerating NKE from a safe stock with steadily growing profits, to something more uncertain that requires a lower multiple. Another thing I'll note is that historically Nike was always primarily a sports company focused on shoe technology. And arguably they are the best in that category. But in the last decade they also seemed to become a ubiquitous fashion brand. So much so that a few years ago almost everyone I knew were wearing Nike's casually, for sport and even in the office. Whenever something becomes so popular that even grown men are wearing them to the office, you know it won't remain in fashion for long.