When you sell the stock of a company, your profits are partially paid for by people who buy stock in the company. It's true of anything that appreciates in value that people who held the thing that appreciated in value benefit from selling that asset to people who buy it at the appreciated price, often themselves hoping to similarly profit. What makes a Ponzi scheme a Ponzi scheme is that, among other things, this is the only source of value and the appreciated price in no way reflects any actual value other than a claim on future investments.