MicroStrategy (MSTR) became the most heavily shorted stock in the United States on February 25, 2026. Short interest in the company reached 14% of its total market capitalization. Market reports indicate the surge stems from sophisticated arbitrage strategies rather than bearish fundamental sentiment.
Traders are executing a basis trade by shorting MSTR shares while maintaining long positions in spot Bitcoin ETFs. This strategy targets the premium at which MicroStrategy shares trade relative to the net asset value of its Bitcoin holdings. The paired trading approach reflects complex market dynamics instead of a negative outlook on the company's future.