Exact Sciences Shares Rise After Investment Firm Increases Stake

William Blair Investment Management boosts position in medical research company by over 25%

Published on Mar. 2, 2026

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William Blair Investment Management LLC has increased its stake in Exact Sciences Corporation (NASDAQ:EXAS) by 26.5% in the third quarter, according to a recent SEC filing. The firm now owns 2,555,051 shares of the medical research company's stock, representing about 1.35% of Exact Sciences' total shares outstanding.

Why it matters

Exact Sciences is a leading molecular diagnostics company focused on the early detection and prevention of cancer. The increase in ownership by a major institutional investor like William Blair suggests confidence in the company's long-term growth prospects as it continues to develop innovative cancer screening tests like its flagship product, Cologuard.

The details

According to the filing, William Blair Investment Management acquired an additional 534,881 shares of Exact Sciences during the third quarter, bringing its total position to 2,555,051 shares. This represents a 26.5% increase in the firm's stake in the company. Exact Sciences is known for its Cologuard test, a non-invasive, stool-based DNA screening test for colorectal cancer that was developed in collaboration with the Mayo Clinic.

  • William Blair Investment Management filed its 13F report for the third quarter of 2026 on March 1, 2026.

The players

Exact Sciences Corporation

A molecular diagnostics company headquartered in Madison, Wisconsin, dedicated to the early detection and prevention of cancer. The company's flagship product is the Cologuard colorectal cancer screening test.

William Blair Investment Management LLC

A Chicago-based investment management firm that manages over $100 billion in assets for institutional and individual clients worldwide.

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The takeaway

The increased investment by William Blair in Exact Sciences underscores the market's confidence in the company's innovative cancer screening technologies and their potential to drive long-term growth. As Exact Sciences continues to expand its product pipeline and market presence, this latest development suggests the stock could be poised for further gains.