Nike's valuation has almost halved from its yearly highs and the stock is down by nearly 65 percent over the last five years. Despite the declining valuations, Apple CEO Tim Cook has invested more money in the footwear and sports brand. Tim Cook’s latest move in the equity markets offers a telling glimpse into the conviction of one of the world’s most closely watched corporate leaders. The Apple chief executive, who also serves on Nike’s board, has deepened his personal investment in the global sportswear giant with a fresh $1 million stock purchase.