Elon Musk's net worth hits $681 billion, more than double Google co-founder Larry Page's $249 billion wealth, as Tesla's stock surge widens the billionaire gap.

CEO, Elon Musk, reached another personal wealth milestone, with the valuation of his privately held space transportation company, SpaceX, soaring to record new highs, ahead of a planned public offering in 2026.

Elon Musk on Monday became the first person ever worth $600 billion, Forbes said, on the heels of reports that his SpaceX startup was likely to go public at a valuation of $800 billion.

The SpaceX CEO just woke up $168 billion richer and set the bar for the first person estimated to be worth more than $600 billion.

Elon Musk has become the first person to reach an estimated net worth of more than $US600 billion ($A902 billion), according to Forbes magazine.

Elon Musk has grown $216 billion richer this year, thanks to Tesla stock hitting an all-time high and SpaceX doubling in value since the summer.