The two tech titans are in the meanest fight in business. The stakes couldn’t be higher.

The relationship between Elon Musk and Sam Altman progressed from an initial friendship to a bitter rivalry. Here's why.

Then Mr. Altman sneaked into the White House. By Cecilia Kang and Cade Metz Reporting from Washington At President Trump’s inauguration, Sam Altman, the chief executive of OpenAI, was relegated ...