Regulatory Scrutiny and Short-Seller Bets Spark 19.6% Plunge in Profusa Shares Amid Biotech Sector Sell-Off

On Nov. 21, 2025, Profusa shares plunged nearly 19.6% in pre-market trading, marking one of the steepest intraday declines in its recent history. The sharp selloff sent shockwaves through biotech investors, with the stock breaking below key support levels and triggering circuit breakers on major trading platforms.

Analysts point to mounting regulatory scrutiny and delayed clinical trial timelines as potential catalysts. A recent FDA guidance update for biotech firms with extended R&D cycles has created uncertainty among investors, particularly for companies lacking near-term revenue drivers. Short-sellers have also increased their presence in the options market, with bearish bets tripling in the past month according to exchange filings.