Amazon.com (NasdaqGS:AMZN) is reportedly in talks to invest up to US$50b in OpenAI, a move that could make it the AI firm’s largest backer. California’s attorney general is seeking a preliminary injunction in an antitrust case that challenges Amazon’s alleged retail price controls in the US. David Luan, a key executive in Amazon’s artificial intelligence division, has resigned, marking a leadership change in a core technology area. For you as an investor, this mix of AI expansion, legal…