Sound some kind of Ponzi scheme! Using the money from new investors pays to the old investors. Early investors may be lucky enough to grab some amount of profit before it closing up!
It's risky investment, but not a Ponzi scheme. Research PAMM accounts and how they work with Forex. This is like Forex but with crypto currencies instead of fiat currencies. Profits are proportional, if master account makes 1% daily profit today, then all slaves make 1% today no matter how much they invested.