Amazon shares sunk more than 9% on Friday after the company's hefty spending forecast surprised investors who were already wary that the artificial intelligence boom is at risk of becoming a bubble. The e-commerce company on Thursday became the latest tech giant to announce plans for a massive increase in capital expenditures, after Google parent Alphabet, Microsoft and Meta all signaled they expect their spending sprees to continue. Amazon, Alphabet, Microsoft and Meta reported about $120 billi...