In a recent interview with Dua Lipa on her podcast, At Your Service, Apple CEO Tim Cook discussed something that he and Apple almost never address: the succession plan they have in place regarding the company’s leadership.

The mere thought of Tim Cook’s inevitable retirement is enough to send shivers down the spines of many of those on Wall Street. Cook is adored by both institutional and retail investors because he has seemingly achieved the impossible: sending Apple to heights even Steve Jobs probably never dared dream. Under Cook, Apple has reached a nearly $3 trillion valuation, making it the most valuable company in the world, by a long shot.

A CEO shakeup is one of the most nerve-wracking events any company can go through. It brings uncertainty, which sprouts anxiety, which makes workers and shareholders nervous—and that’s just for regular companies. Apple is clearly no regular company. It has billions of users around the globe. A CEO change can introduce a difference in product vision or philosophy, and thus has the potential to send once-loyal customers to other brands, should changes be too severe.

The good news: Cook, who has been with Apple for 25 years—more than 12 as CEO—revealed that he plans to remain at the company “for a while.” Of course, “for a while” is subjective. It could mean two more years, or five. But, acknowledging life’s uncertainties, Cook said that he could “step off the wrong curb tomorrow” and revealed that if anything were to happen to him, Apple already has “very detailed succession plans” in place.

Cook wouldn’t comment on who is in line to replace him at the helm. But he did say that he “really want[s] the [next CEO] to come from within Apple,” and he views part of his role as making sure the board has several internal candidates to choose from.

So, who could Apple’s next CEO be if the company does indeed choose an internal candidate? Here are four likely possibilities:

CRAIG FEDERIGHI, SENIOR VICE PRESIDENT, SOFTWARE ENGINEERING

If I were a betting man, I’d place my wager on Craig Federighi as being the most likely to be named Apple’s next CEO. Aside from Cook, Federighi is probably the most recognizable face at Apple. The public may know him as that silver-haired goofball in the company’s keynote videos, but inside Apple, he’s one of the critical components of the leadership team.

Federighi oversees what is arguably Apple’s most important product: iOS, the operating system that powers the iPhone—the company’s main money maker—as well as macOS, the operating system that powers Apple’s Macs. But far from just being a software guy, Federighi has a quality that is critical for any Apple CEO. As I’ve learned from interviewing him many times, Federighi has a deep understanding of the role technology plays—for good and for evil—in the modern world. He’s keenly considerate of how it influences everything from our personal privacy to social cohesion to geopolitics.

Federighi also has another thing going for him: his age. At 56, he’s the youngest on this list. That means he’s also likely to stick around as CEO the longest. And after the 63-year-old Cook leaves, employees and investors are going to want long-term stability at the company, not a CEO who may retire just five years after being appointed.

GREG JOSWIAK, SENIOR VICE PRESIDENT, WORLDWIDE MARKETING

There’s probably no one on this list who knows Apple better than Greg Joswiak, or “Joz,” as those close to him know him. Joswiak, 60, has been at Apple for 37 years, having arrived at the company in 1986. That means he’s seen all the ups and downs. He first joined after Jobs was ousted, so he knows what it’s like to work at Apple under leadership that has poor vision. He’s also intimately familiar with—and played a big part in—Apple’s renaissance once Jobs came back to the company in 1997. Joswiak helped develop the original iPod and iPhone, the products that saved the company.

Joswiak, in other words, has seen it all. He has the experience to understand what does and doesn’t work for Apple, its customers, and its shareholders. And as senior vice president of worldwide marketing, Joswiak probably has a better understanding of Apple’s narrative and the way the company presents itself to the world than anyone else in Cupertino. The best CEOs are masters at being able to convey a unified vision of the company to employees and customers. Joswiak can do that.

EDDY CUE, SENIOR VICE PRESIDENT, SERVICES

Apple has moved well beyond just being a hardware company. In recent years, it has invested heavily in services—led by Eddy Cue—which include digital media stores, such as the App Store and iTunes Store; advertising via those stores; cloud services including iCloud Plus; streaming services, such as Apple Music and Apple TV Plus; and such payment services as Apple Pay.

In Apple’s fiscal 2023, these services earned Apple $85.2 billion, making it the company’s largest revenue category after the iPhone. Cue gets the credit for that. And given the amount of money that Services now generate, it is likely to become only more important to Apple in the years ahead, since the revenue generated by services is recurring, and the margin on services is much higher than the margins on physical goods.

If services are critical to Apple’s growth in the future, who better to lead Apple than the senior executive who built its services division into an 11-figure juggernaut? And Cue, 59, has been at the company for a long time, too, starting in 1989. That means that he, like Joswiak, has seen the company’s ups and downs, and knows what works and what doesn’t.

JEFF WILLIAMS, CHIEF OPERATING OFFICER

And then there is Jeff Williams, Apple’s current chief operating officer (COO). When you consider the sheer volume of products Apple manufactures and ships every year, and the dozens of disparate teams that each do their part to get those products out the door, it’s amazing that things run as fluidly as they do at Apple. A large part of that is due to the fact that all these operations are overseen by Williams, 60.

Before Cook became CEO, in 2011, he was Apple’s COO. Many pundits argued that an ops guy wasn’t the right choice to follow in the footsteps of a creative visionary like Jobs. Cook clearly proved them wrong. Williams is as competent a COO as Cook was, and he’s also not just an ops man himself. He currently heads the company’s design team and oversees Apple’s burgeoning health initiatives, including the health features built into the Apple Watch. While health tech is still a relatively nascent area for Apple, the global digital health market is expected to reach $1.5 trillion by 2030. If Apple can capture even a fraction of that market through its consumer health tech, it could help the company generate tens of billions more in annual revenue while enabling its users to lead healthier lives—something Williams likely understands better than anyone at the company.

Perhaps no one, aside from Cook, has as comprehensive an understanding of what it takes to keep all the widgets moving and wheels spinning at Apple as Williams does. And the fact that he also has an engineering background and has spearheaded many of Apple’s design and health initiatives means that he’s at least as qualified, if not more, than Cook was when he assumed the role of Apple CEO.

SO, WHO WILL GET THE CEO ROLE?

While these four candidates are likely to top Apple’s internal list of possible successors, it’s worth noting that Apple’s board isn’t required to promote someone from within the company. It’s entirely within the board’s authority to appoint a CEO from outside Cupertino. However, doing so could be devastating to Apple employees, investors, and Apple’s loyal customer base.

Apple has always been a company with a cohesive vision and culture—at least, under Jobs and Cook. It’s hard to see how an outsider could easily fit into an environment with so much history and so many moving parts.

Of course, should the board choose one of these four likely candidates, or anyone else from Apple’s current leadership team, there’s no guarantee that the person will take the job. Some may like where they are. Some may not want the stress of running the most profitable company on the planet. And some may never have counted it as one of their professional goals.

As Cook told Dua Lipa, “I didn’t have a dream to be CEO of Apple. It was beyond what I would have ever dreamed for myself. But it happened, and I want to make sure it can happen for other people as well.”