NEW YORK, Feb 5 : Elon Musk used a common two-step merger process in SpaceX's purchase of xAI that had the dual benefit of avoiding the repayment of billions of dollars in debt while giving shareholders a tax advantage, according to people familiar with the transaction. It also protects SpaceX from any legal liability from xAI.    The deal, announced on Monday, creates a $1.25 trillion company with plans to go public later this year to help finance Musk's ambitions to put data centers in space.