OpenAI sent a letter Thursday to investors and banking partners warning that it expects Elon Musk to make "deliberately outlandish, attention-grabbing claims" as his lawsuit against the AI lab heads to trial in April. The trial will mark a public escalation of Musk's years-long feud with OpenAI, and the company's letter serves as an attempt to preempt and alleviate investors' concerns. OpenAI has raised billions of dollars from venture capitalists, and its valuation has swelled to $500 billion.