Tesla could increase the number of workers at its Fremont, Calif., factory by roughly 50%.
Investors show confidence as companies benefit from a weaker yen and Abenomics.
U.S. stocks haven't had two down days in a row in a month.
Automakers used to spending billions on R&D want to develop their own self-driving systems. Tech giants will have to work hard to convince them to change their minds.