A ponzi is where you use the money from new investors to pay off earlier investors.
Early investors in startups cash out during later funding rounds or acquisitions.
QED.
Early investors in startups cash out during later funding rounds or acquisitions.
QED.
In a Ponzi scheme, there is a central party that refunds investors on demand, and does so with money from new investors.
A Ponzi scheme is always a fraud, frothy valuations in a bubble might indicate market manipulation, but not _necessarily_ fraud.