There are micro-bubbles all the time that depend on ease of equity and cheapness of debt. Ever heard of Amazon Aggregators?

I forget the exact study, but investments with lottery like payoffs tend to be systemically overvalued whether it's micro-cap stocks, short-term options, or innovative startups. People feel better about a chance of extremely high returns than they do about giving that chance up. Until this year, any new business could be given a lottery like payoff (or even be turned into a ponzi scheme).