Watch out for indigestionIllustration: Fortunate JoaquinThey promise to be the biggest stockmarket debuts ever. On June 11th SpaceX reportedly hopes to raise $75bn from investors, by issuing shares that will begin trading on the Nasdaq exchange the next day. Elon Musk’s rocketry firm will probably soon be followed by two other mammoth listings. Anthropic, an artificial-intelligence lab, filed draft paperwork for its initial public offering on June 1st; OpenAI, a competitor, is expected to do so ...