Elon Musk could pass an unthinkable wealth threshold, becoming the world’s first trillionaire, depending on investors’ excitement for SpaceX shares when it goes public. If the company surpasses a valuation of about $1.7 trillion, then Musk’s slightly more than 40% stake, combined with his Tesla shares, would make him the first man with a net worth eclipsing 13 figures. The calculation omits restricted shares that SpaceX has granted to Musk, but which haven’t been earned, though it includes options he could exercise shortly.