Apple shares declined in early trading on Monday as Tim Cook's 15-year tenure as CEO concludes, with senior vice president of hardware engineering John Ternus taking over on September 1. Cook, who quadrupled Apple's yearly revenue and grew its market value from $350 billion to over $4 trillion, will remain as executive chair. Meanwhile, tech stocks were volatile, with AI optimism from Nvidia earnings clashing with increased odds of a Fed rate hike.