Already the world’s richest man, worth roughly $696bn before the float according to the Bloomberg Billionaires Index, Musk holds a 42% stake in the rocket-cum-AI company.

With SpaceX beginning trading at a $1.77tn valuation, selling 555.6 million shares at $135 apiece, estimates put his holding at between $743bn and $866.5bn, enough to cement trillionaire status before markets close.

The scale defies comprehension. Oxfam calculates that spending $1m a day, it would take 2,740 years to exhaust $1tn. Musk will be more than three times richer than the world’s second-wealthiest man, Google co-founder Larry Page, at $304bn.

Historical comparisons are starker still. As a trillionaire, Musk would command roughly 3% of US GDP – double John D. Rockefeller’s 1.5% in 1937 and dwarfing Andrew Carnegie’s 0.5%.

Guido Alfani, professor of economic history at Bocconi University, says that measured by the labour his fortune could purchase – some 557,800 workers in 2025, against Rockefeller’s 116,000 – Musk “might be the wealthiest person who has ever lived”, excluding rulers whose wealth was indistinguishable from the state’s.