Elon Musk has finally signaled that the most closely watched private company in space is preparing to step onto public markets, and the numbers being floated are big enough to reshape the global wealth leaderboard.

On Monday, Forbes reported that he became the first person to reach a net worth of $600 billion.

In November, Tesla shareholders approved a $1 trillion pay plan for Musk, the largest corporate pay package in history, as investors endorsed his vision of morphing the EV maker into an AI and robotic...