Apple reported a record quarterly performance driven by a sharp rise in iPhone revenue, yet investors sent its shares down about 8% in after-hours trading after the company cautioned that supply constraints could disrupt deliveries of Macs, iPhones and iPads in the coming months.

The market reaction may look counterintuitive at first glance. The company posted record results and pointed to a strategy of disciplined investment in artificial intelligence that is now beginning to pay off. But the warning on supply chains overshadowed the numbers, reviving concerns about how the global AI infrastructure boom is squeezing component availability and driving up costs across the technology industry.

Apple's revenue from iPhone sales grew significantly during the quarter, providing the main engine behind the record figures. Executives also presented the company's cautious approach to AI as a deliberate advantage, suggesting that by focusing on targeted product-level features rather than racing to build enormous data-centre capacity, Apple has avoided some of the heavy spending weighing on other big technology companies.

The optimism did not last. During the earnings call, company officials warned that future supply bottlenecks could affect production and availability across several major product lines, including the Mac, the iPhone and the iPad. The caution echoed a pattern spreading through the electronics sector, where competition for memory chips and other components has intensified as technology firms pour billions into AI infrastructure.

Memory costs are emerging as a particular pressure point. Rising prices for memory chips, fuelled by surging demand from AI data centres, threaten to squeeze Apple's profit margins even while consumer demand for its devices remains robust. Analysts noted that the combination of higher input costs and potential production delays could take some of the shine off the record quarter in the months ahead.

The market's reaction also reflected a broader reassessment sweeping the technology sector, where investors have grown wary of companies exposed to the huge costs of the AI build-out even as demand for AI-related hardware climbs. In Apple's case, the concern is twofold: tighter supplies could limit how many devices the company can sell, while rising component prices could erode the margins on the devices it does ship.

The earnings call carried a symbolic dimension as well. It was reported to be Tim Cook's final earnings call as chief executive, adding extra attention to how the company is positioning itself for a leadership transition. Cook's departure from the quarterly ritual marks the end of an era in Apple's relationship with investors, and the focus now shifts to how his successor will handle the mounting challenges around supply chains and AI spending.

The wider backdrop is a technology sector gripped by an AI-driven investment wave. The scramble to build data centres and secure computing capacity has pushed up demand for memory chips, semiconductors and other components, creating bottlenecks that are rippling through the supply chains of even the largest hardware makers. Apple's warning is one of the most prominent signs yet that this pressure has reached mainstream consumer electronics.

For investors, the immediate question is whether Apple can convert its product strength into sustained earnings growth despite these external pressures. The record quarter shows demand remains healthy, particularly for the iPhone. But with supply constraints looming and memory prices climbing, the path ahead may be bumpier than the headline numbers suggest. The sharp after-hours share drop was a reminder that, in the current climate, even record results can be overshadowed by what lies ahead.