Apple CEO Tim Cook is stepping down

The big picture: Apple is one of the most valuable companies in the world.

Driving the news: Cook will become executive chairman of Apple on Sept. 1, the company said Monday.

• Ternus, senior VP of hardware engineering, has been widely viewed as Cook's likely successor.

What they're saying: "It has been the greatest privilege of my life to be the CEO of Apple and to have been trusted to lead such an extraordinary company," Cook said in a statement.

By the numbers: Apple's market value grew from about $350 billion in 2011 to roughly $4 trillion under Cook's tenure.

• Annual revenue nearly quadrupled to more than $400 billion.
• Active devices topped 2.5 billion worldwide.

What's next: Ternus steps in at a pivotal moment, with Apple under pressure to prove it can still deliver its next breakthrough — particularly in AI.

• "Cook leaves a lasting legacy in Cupertino and there will be a lot of pressure on Ternus to produce success out of the gates especially on the AI front," Wedbush Securities analyst Dan Ives wrote Monday in a research note.

• "While there were rumors of Cook leaving as CEO, investors will for now have more questions than answers around the timing and what this means for the broader Apple strategy."

Go deeper... Axios C-Suite: Get to know John Ternus, Apple's CEO-in-waiting

Editor's note: This story was updated with additional information throughout.