The stock closed at US$108.03 Wednesday in New York, up from a split- adjusted US$53.74 on the day Mr Cook took over the top job. Mr Cook has used buybacks and dividend increases to help ensure that Apple stock outperformed the S&P 500 even as sales slowed. In 2013, he extended a share-buyback program sixfold ahead of the introduction of the iPhone 6 the following year, which reignited growth. BLOOMBERG