This week marks one of the most consequential earnings periods of the year, with Amazon, Meta, Alphabet and Microsoft reporting on Thursday, followed by Apple on Friday. Together, these five companies account for nearly a quarter of the S&P 500, positioning their results as a key driver of broader market direction. At the centre of attention is artificial intelligence. Collectively, these companies are expected to spend close to US$700 billion this year to fuel growth, but investor focus is shifting decisively from the scale of investment to the returns it ...