Elliott Management has taken a significant stake in coffee chain Starbucks and is engaging with management to find ways to improve the company's share price, the Wall Street Journal reported Friday, citing people familiar with the matter.Representatives for Elliott did not return a request for comment. A Starbucks spokesperson said the company does not comment on rumors and speculation. Starbucks shares jumped 5% on the news.Elliott is one of the most prolific activist investors and one of the largest hedge ...