While some may want a higher dividend, money spent on dividends is not money reinvested into the company. I own the rangebound Legal & General and every time they pay one of their (high) dividends, the share price drops by more than the dividend on the ex-div. date so I sell before then anyway.
Nike had three retail partners in the US, that is, Dick's Sporting Goods, JD Sports, and Hibbett. Now Nike only have two. So, unless anything changes, it could be looking good for JD in the US.
Otherwise, I think DramChart is right with his algorythem theory. It is interesting that the sudden rise in the share price did not occur until a few hours after the major buy.
This is JD's fourth major move into the US so they are not without experience in this region which is the largest sportswear market in the World. The current price is probably just a cyclical movement and may well present a buying opportunity.