NEW YORK, April 2 : Billionaire Elon Musk’s SpaceX has had discussions with Saudi Arabia’s Public Investment Fund about PIF potentially taking an anchor stake of around $5 billion in the space company’s IPO, according to two people familiar with the matter. The investment would partly prevent dilution of PIF’s existing stake of just under 1 per cent in SpaceX, the sources said. The rocket maker has been lining up anchor investors well ahead of its stock market debut, three other sources said.