SpaceX and the rest: here’s why giga-scale IPOs could be a sign of a market bust to follow

History suggests that when equity supply turns into a gush, the pool of liquidity often begins to dry up. To the extent new mega-listings in America are a sign of euphoria, that could happen again. “Bull markets are born on pessimism, grow on scepticism, mature on optimism, and die on euphoria,” said John Templeton.