Amazon shares tumble as it joins the Big Tech AI spending spree  BBCAmazon stock falls 10% on $200 billion spending forecast, earnings miss  CNBCAmazon’s $200 Billion Spending Plan Raises Stakes in A.I. Race  The New York TimesAmazon’s stock falls after earnings. Here’s why investors are spooked.  MarketWatchAmazon.com Announces Fourth Quarter Results  Business Wire