A crypto analyst is sounding the alarm over MicroStrategy's (MSTR) business model, calling it a "giant Ponzi scheme." In an email to clients, Jacob King of crypto newsletter Whale Wisdom slammed MSTR's strategy of issuing debt to buy Bitcoin. He argues that this model is unsustainable and will ultimately lead to the company's collapse. "They issue debt to buy BTC, which pumps the price of BTC, which increases MSTR's market cap, which attracts more investors," King wrote. "The higher the valuation, the more debt they can issue, the more BTC they can buy. But this cycle only works if the price of BTC keeps going up. If BTC goes sideways or down, the whole thing collapses." King believes that this model is a Ponzi scheme, similar to that of FTX and Enron. He warns that when MSTR's scheme collapses, it will be "historic." MicroStrategy did not immediately respond to a request for comment.