Elon Musk's entrepreneurial career has always been a blend of unfulfilled promises and astonishing achievements. People are literally willing to take his fantasies and dreams at face value. Toyota sells six times as many cars as Tesla, yet Tesla is worth three times as much on the stock market as its Japanese rival.

With the IPO of SpaceX, however, the world's first trillionaire has finally lost touch with reality. By 2055, a million people are to settle on Mars; vast data centres are to be built in space. That is pure science fiction. A market capitalisation of nearly $2 trillion is a bet on the future without any basis in reality. To justify such a price on conventional metrics, SpaceX would have to lift its AI revenue from $3.2 billion to $322 billion by 2030, multiply its total revenue 180-fold by 2040, and turn a $5 billion loss into $2.7 trillion in profits by 2040, so as to reach a market-standard ratio of market capitalisation, revenue and profit. The fact that numerous major banks and financial analysts are reported to consider such a scenario plausible says rather more about their business interests than about their analytical abilities.