Apple co-founder Steve Jobs died in 2011. Many thought his ability to lead the technology company would be impossible to replace. However, the current head of Apple, Tim Cook, seems to be doing extremely well.

    Cook was at first believed to be little more than a caretaker for Apple after Jobs' death. But Cook has continued to build Apple with his own skill and ideas. He will celebrate his ninth year as Apple's Chief Executive Officer (CEO) Monday.

    Training Cook to take over the company was "one of Steve Jobs' greatest accomplishments," said Apple analyst Gene Munster.

    The company's stock market value was $400 billion when Cook became CEO. Its stock is worth five times that amount today. It is the first U.S. company to have a market value of $2 trillion.

    However, Cook has faced many problems as the company's head. They included a slowdown in iPhone sales as smartphones outgrew their newness. Another was an argument with the FBI over user privacy. In addition to that is the U.S. trade war with China which threatens to force up iPhone prices, and the pandemic that has closed many Apple stores and sunk the economy into a deep recession.

    Cook has also done some things that Jobs refused to do. Apple now pays a dividend, which Jobs did not want. Cook also has used his position to become a supporter of civil rights and renewable energy. In 2014, he became the first openly gay CEO of a major American company.

    However, Apple has not brought out a product that creates a new market as it did with the iPhone. Its smartwatch and wireless ear buds are good products, but not nearly as revolutionary as the iPhone was.

    Cook and other company officials have suggested that Apple wants to make a revolutionary product in the field of augmented reality. It would use phone screens or high-tech eyewear to create digital pictures. But, Apple has not yet offered such a product.

    Apple also appears to be behind in the creation of artificial intelligence, especially for voice-activated digital assistants. Although Apple's Siri is used on Apple devices, people have accepted Amazon's Alexa and Google's digital assistant more easily.

    Cook has also made some mistakes.

    In 2017, Cook angered iPhone users by slowing the performance of older iPhones with software updates. The users believed the company did it to force them to buy new and more costly iPhones. The company later paid $500 million to end a legal case over the issue. Apple also faced government investigations into its attempts to lower its corporate tax.

    Cook has been most worried about the fall in sales of iPhones as people keep the devices longer. Four years ago, he rebuilt the Apple app store which provides programs for use on Apple devices. He placed importance on subscriptions services that can be used by the 1.5 billion iPhones already in use. That effort has added more than $50 billion each year to Apple's income.

    I'm Susan Shand.