SEATTLE and CUPERTINO — Amazon and Apple reported quarterly earnings on Thursday, capping a week in which investors scrutinised whether surging artificial intelligence spending was translating into revenue at the largest US technology companies.

The reports followed results from Microsoft and Meta earlier in the week, which put AI-related capital expenditure at the centre of investor attention. Data-centre outlays emerged as the key metric determining whether Big Tech valuations remained justified.

For Amazon, attention centred on growth at Amazon Web Services, the company's main profit engine, and on spending to expand AI infrastructure. Apple faced questions over iPhone demand, services revenue and the rollout of its delayed Apple Intelligence features, alongside the impact of US tariffs on hardware costs.

The combined market value of the companies reporting this week runs into trillions of dollars, giving their results outsized influence over the Nasdaq and S&P 500. Executives were expected to defend heavy AI investment against pressure for near-term returns, echoing the tone set by Microsoft and Meta.

Wedbush Securities said the reports would test whether the AI investment cycle was still delivering measurable growth, or whether investor patience with rising capital expenditure was beginning to wear thin.