Tim Cook is stepping down as CEO of Apple after a 15-year tenure during which the company became the first publicly traded U.S. firm to reach a $1 trillion market capitalization, among other milestones. His departure marks only the third CEO transition in Apple's history, following Steve Jobs and Jobs' predecessor John Sculley-era leadership changes, making it one of the most closely watched handoffs in corporate America.

Cook announced in April that he would leave the CEO role at the end of August. While he is vacating that position, he will remain with the company as executive chairman. John Ternus, most recently Apple's senior vice president of hardware engineering, will succeed him as CEO. Ternus is a hardware veteran who oversaw engineering across core product lines, and his elevation signals continuity in Apple's product-first culture — a contrast to the 2011 transition, when Cook, an operations expert, took over from Jobs, the company's iconic product visionary.

Cook took the top job in August 2011, when Apple co-founder Steve Jobs resigned six weeks before his death. Jobs first met Cook in 1998 and persuaded him to join Apple that same year, beginning his career at the company as senior vice president for worldwide operations. At the time, Apple was fighting for relevance; under Cook it grew into the most valuable company in the world, with the market-cap milestones to show for it.

"As you know, I am not leaving Apple. But I am stepping away from a role that I have loved deeply," Cook wrote in a memo emailed to all employees on his final day. "I will miss this work in ways I can only begin to imagine, even as I remain completely at peace with my decision."

"Together, we have created something far greater than any one of us could have imagined or accomplished alone. And that's the secret to our success. We bring out the best in each other. We lift each other up," Cook said. "We have made it possible to leave our 'dent in the universe,' as Steve once described it, because of who we are and what we believe, because of what we value and how we see the world," he added.

Under Cook, Apple expanded into new product and service categories, building a broader consumer tech ecosystem on top of the MacBook, iPhone, and iPad. In 2014, the company announced the Apple Watch as it entered the wearable health tech market, and also launched Apple Pay that year, leveraging its base of consumer device users to compete in mobile payments.

In 2015, Apple Music marked the company's pivot from iTunes to a subscription-based streaming model, and in 2016 Apple debuted the AirPods, which supercharged growth of its wearables division. The company continued broadening its services with the launch of Apple TV+ and Apple Card in 2019. This shift toward recurring services revenue became a defining strategy of the Cook era, complementing hardware sales with subscription and payments income.

Apple also reached a series of major corporate milestones during Cook's leadership. It became the first U.S.-based publicly traded company to hit $1 trillion in market capitalization in 2018, reached $2 trillion in 2020, surpassed $3 trillion for the first time in 2022 during intraday trading, and crossed $4 trillion in October 2025. In July 2026, it briefly overtook Nvidia as the company with the largest market cap.

Over the years, Apple has vied with ExxonMobil, Nvidia, and Microsoft for the title of most valuable publicly traded U.S. company, with the top spot regularly changing hands. Apple ranked first for much of the 2013 to 2018 period. The company currently has a market cap of roughly $4.6 trillion, ranking second behind Nvidia's $5.25 trillion and ahead of Microsoft's $3.79 trillion valuation. Nvidia's rise to the top spot has been driven by demand for AI chips, a market where Apple has taken a different path with its own in-house silicon, an area Ternus knows well from his hardware engineering background.

Apple plans to hold the first major event under new CEO John Ternus on Sept. 9, when it will unveil its newest iPhone and could potentially reveal the long-awaited foldable iPhone. A Reuters report noted that analysts expect Apple to launch a foldable iPhone, entering a new segment of the smartphone market to compete with Samsung. That event will serve as the first public test of the Ternus era and a signal of whether Apple intends to keep its traditional product cadence intact.

In his letter, Cook said he takes "enormous comfort in handing the helm to someone as brilliant and wonderful and capable as John," adding that few people "understand what it takes to build products that change the world the way John does and I could not be more excited for his leadership."