Apple (AAPL) shares fell 1.8% on Monday as John Ternus prepares to succeed Tim Cook as chief executive. Ternus has led Apple's hardware engineering organization, a role that has placed him at the center of the company's product development across the iPhone, Mac, and newer device lines. The leadership change comes as Apple approaches a $5 trillion valuation and faces mounting pressure to find new sources of growth beyond the iPhone and its services business. Investors are closely watching how the transition may shape the company's strategy, spending, and product roadmap.

A Much Larger Company Than Cook Inherited

Ternus will inherit a company that expanded dramatically under Cook's leadership. When Cook became CEO in 2011, Apple sold roughly 72 million iPhones per year. Counterpoint Research now estimates the company will sell about 255 million units this year.

Cook also grew Apple's services business — which spans the App Store, iCloud, Apple Music, and advertising — and maintained a steady product release cycle. During his tenure, the company returned more than $1 trillion to shareholders through dividends and share buybacks. The stock has gained more than 2,200% since he took charge.

AI and Siri Among Top Priorities

Ternus will face immediate pressure to strengthen Apple's artificial intelligence strategy. The company has announced new Siri features designed to handle more tasks, though early testing showed that some responses remained slower than those from rival assistants. Apple has lagged some competitors in shipping broadly available generative AI features, an area where rivals including Google, Microsoft, and Samsung have moved faster to embed assistants across their products.

Daniel Newman, CEO of Futurum Group, said Apple must identify the next major computing platform after smartphones. He noted that users already access services such as ChatGPT and Claude through Apple devices, which gives the company a strong position in consumer AI.

Valuation and Supply Chain Risks Remain

Apple stock trades at about 33 times next year's earnings, compared with roughly 20 times for the S&P 500. The company's earnings growth is also running at about half the pace of the broader market, drawing increased attention to its valuation.

Apple also faces rising supply chain costs. AI companies are competing for memory, storage, and logic chips, which can push component prices higher. The company remains heavily dependent on China for production, while US-China trade tensions continue to pose a risk — an exposure it has sought to reduce by expanding assembly in India and Vietnam.

Still, Apple continues to draw demand from its core products. The iPhone 17 Pro has benefited from camera and battery upgrades, and Mac demand has improved as Apple-designed chips support large language models directly on devices.

A foldable iPhone is expected to feature in Ternus's first major iPhone launch event, marking Apple's entry into a category where Samsung and Chinese vendors already compete. IDC estimates the device could capture 40% of the foldable smartphone market by the end of 2027. Ternus will also oversee Apple's search for new product categories as competition in AI and consumer hardware intensifies.