Elon Musk announced plans to build a giant chip factory in Austin, Texas.

Elon Musk took the stage in Austin last night for what he called a "profoundly important announcement … the most epic chip-building exercise in history, by far."

That’s about 100 million to 200 million artificial intelligence chips, which will be used to power Musk’s products, from his self-driving vehicles to his Optimus humanoid robots to rockets – and event...