David Einhorn, President of Greenlight Capital, has declared that the market has reached the 'Fartcoin' stage of the market cycle, according to an investor letter obtained by CNBC. Einhorn describes Fartcoin as a cryptocurrency that serves no purpose other than trading and speculation, highlighting it as an example of the speculative behavior that has escalated beyond common sense in the current bull market. He notes the rapid rise of Fartcoin to a market value nearing $2 billion, with a peak at $2.5 billion, surpassing many U.S.-listed companies. Einhorn points out the emergence of other meme coins like $TRUMP and Melania Trump's coin, suggesting that the market might be transitioning from the Fartcoin stage to a new phase dominated by Trump-related meme coins, predicting further volatility. Additionally, Einhorn's firm has taken advantage of the crypto market's volatility by shorting leveraged ETFs linked to MicroStrategy, a strategy that proved profitable in the fourth quarter due to MicroStrategy's volatility and an arbitrage trade.