U.S. Cancer Diagnostics Stock Loses $1.3 Billion in Market Value in One Day

Guardant Health (NASDAQ: GH) plunged more than 10% on the 10th, closing at $77.88 and erasing roughly $980 million in market capitalization—about ₩1.3 trillion. With trading volume topping 4.9 million shares, unusually heavy selling pressure has heightened concerns over short-term volatility.

The company’s growth story remains intact: its companion-diagnostic role in Japan’s approval process for the cancer drug Enhertu has been spotlighted, and analysts have outlined a potential $2.1 billion revenue scenario by 2029. At the same time, filings showing that some institutional investors reduced their stakes have prompted interpretations that overvaluation concerns and profit-taking selling coincided. ()

Headquartered in Palo Alto, California, Guardant Health is a precision-oncology and liquid-biopsy specialist known for its blood-based genomic test Guardant360 and its Shield blood test for early colorectal cancer detection. Co-founded in 2012 by Helmy Eltoukhy and AmirAli Talasaz, the company is regarded as a key player in noninvasive early cancer detection and the expanding companion-diagnostics market. ()