Based on your phrasing of the SEC definition, the real estate market also feels like it fits the bill :-/

Edit: parent comment was edited, originally said:

> It actually matches the SEC definition of a Ponzi scheme haha, which happens to be a little bit less restrictive than a traditional definition.

> It's a negative sum wealth redistribution scheme the takes money from new entrants and gives it to miners and to old entrants. The miner portion is what makes it negative-sum.