That's factually not the definition of a Ponzi Scheme. To be a Ponzi Scheme, you have to continually pay existing investors with the money of new investors, thus requiring an every increasing number of new investors. The person running the scheme is making payments out of a fraudulent investment fund of some sort. But in this case, buyers got exactly what they paid for- shares of dogecoin- and they did not buy it from Musk, nor was Musk managing the asset in any way. It was by no definition anywhere close to a Ponzi Scheme. Musk held shares of asset that he in no way controlled and he hyped up the value using his public platform and then sold his shares when the value was artificially high due to his influence. What Musk did was absolutely not a ponzi scheme, but it was a classic pump and dump. Illegal if you're doing it with stocks. With crypto, buyer beware.