The Financial Post reports in its Thursday, Feb. 6, edition that last week, DeepSeek's emergence as an artificial intelligence threat wiped out half-a-trillion dollars in Nvidia's value. A Bloomberg dispatch to the Post reports that Alphabet's disappointing earnings also raised concerns about its capital expenditures, leading to its stock facing a significant drop -- marking the worst in over a year. These events reflect broader worries about whether AI spending will yield returns. The "Magnificent Seven," which includes major players driving S&P 500's earnings and returns, now see decelerating profit growth even as their expenditures increase. The concerns raise a threat to their lofty valuations, given the group trades at a 40-per-cent premium to the broader S&P 500 based on forward price-to-earnings ratios. That spread has already been ebbing, falling from a peak of 70 per cent back in 2023. Year-over-year earnings growth for the biggest companies peaked in late 2023 and is expected to slow for a fifth consecutive quarter, according to Bloomberg Intelligence. Five of the seven firms have reported results so far in this period, while Amazon is due on Thursday and Nvidia is expected later in the month.