Biotech Stocks Surge 5x in a Year, Plunge 7% in a Day

Arrowhead Pharmaceuticals (NASDAQ: ARWR) closed at $73.50 on May 29, down 7.02% from the previous day, on trading volume of approximately 1.16 million shares. Its market capitalization fell to about $10.3 billion, erasing roughly $679 million (₩9.2 trillion) in one day.

On May 27, at the European Association for the Study of the Liver (EASL) 2026 conference, Arrowhead presented interim Phase 1/2a data for ARO-INHBE, its obesity and metabolic dysfunction-associated steatohepatitis (MASH) candidate, reporting positive outcomes such as reductions in liver fat. In the first quarter, the company posted revenues of $264 million and earnings per share of $0.22, extending its profitable streak.

Arrowhead Pharmaceuticals is a U.S. biotech company developing RNA interference–based therapies for rare and metabolic diseases. Its treatment for familial chylomicronemia syndrome, REDEMPLO, has been approved in the U.S. and select other markets, marking its entry into commercial operations. Recent clinical progress with candidates like plozasiran and growing optimism around its obesity program have driven the stock more than 400% higher over the past year, raising questions about its current valuation.