According to Odaily, David Einhorn, the billionaire founder of Greenlight Capital, has disclosed in a recent letter to investors that the firm has established short positions on two leveraged ETFs associated with MicroStrategy, the largest corporate holder of Bitcoin. These funds, T-Rex 2x Long MSTR Daily Target ETF and Defiance Daily Target 2X Long MSTR ETF, have gained popularity for attempting to double MicroStrategy's returns. Einhorn expressed skepticism, stating that it is more likely that prudent governments should refrain from borrowing trillions from the bond market to engage in Bitcoin speculation, as such actions lack strategic significance.