$XBI, the SPDR S&P Biotech ETF, experienced notable fluctuations on April 8 and 9, 2025. Following a market rally and biosecurity news, the ETF initially showed potential for a rise to the $76-$77 range but instead fell nearly 3%. On April 9, it demonstrated an intraday reversal of approximately 8%, with some stocks within the sector, such as $BBC, experiencing declines nearing 10%. Analysts have pointed to a liquidity crisis as a possible explanation for the drastic changes in value. The ETF's performance has raised concerns, with one commentator noting a decade of stagnant returns for $XBI, while others highlighted the unpredictability of its movements, including a swing from -4% to +5% within a single day.