A crack-up boom is something that can only happen in an economy that relies on fiat money (in either paper or electronic form) and (usually) fiduciary media, as opposed to the gold standard or other physical commodity money, because the available stock commodity places a physical limit on the quantity of money that can be issued and the market discipline imposed by a convertible gold standard helps prevent the overissuance of credit. 2 In the event that they ever become money, electronic cryptocurrencies whose underlying algorithms place inflexible limits on the quantity and rate that new units can be created (or mined) may provide a similar benefit of preventing hyperinflation and a crack-up boom.