CHENGDU, CHINA - MARCH 18: Apple CEO Tim Cook attends a special event marking Apple's 50th anniversary at the Apple Taikoo Li Chengdu store on March 18, 2026 in Chengdu, Sichuan Province of China. VCG | Getty Images Apple shares jumped more than 4% on Thursday, headed for the sharpest rally since August, after the iPhone maker reported better-than-expected quarterly results and issued revenue guidance for the current period that sailed past analysts' estimates. CEO Tim Cook , who is preparing to step down in September after 15 years at the helm, touted the company's performance in the face of significant supply constraints due largely to the global memory crunch. The company said revenue in the fiscal third quarter, which ends in June, will increase between 14% and 17% from a year earlier, while analysts were projecting growth of 9.5%. Apple is seeing continued demand from the iPhone 17 family, which Cook called the "most popular lineup in our history," as well as for a number of Mac models.…