Lexi Critchett / Bloomberg via Getty Images Key Takeaways The U.S. economy has grown increasingly concentrated in AI, with the biggest tech companies now making up about a third of the value of the entire stock market. Companies are investing in AI at a titanic scale, building colossal data centers all over the country to the tune of $400 billion in 2025. As the U.S. economy becomes increasingly concentrated in AI, more economists have warned of catastrophic consequences if it doesn't pan out at the ...