Elon Musk and Jeff Bezos are now worth almost half a trillion dollars

The combined net worth of Elon Musk and Jeff Bezos approached $500 billion on Wednesday, fueled by the unrelenting rally in Tesla Inc. shares and a broad surge in tech stocks that sent the Nasdaq 100 to an intraday record.

The value of the two fortunes—a sum bigger than the market value of Johnson & Johnson and about equal to that of America’s biggest bank, JPMorgan Chase & Co.—is yet another watershed moment in what’s shaping up to be a historic week for billionaires.