Dimensional Fund Advisors Increases Stake in Quest Diagnostics

Institutional investor boosts ownership in medical research company to over 1.7% of outstanding shares

Mar. 6, 2026 at 9:25am

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Dimensional Fund Advisors LP, a major institutional investor, increased its stake in Quest Diagnostics Incorporated by 0.3% in the third quarter of 2025. The firm now owns approximately 1.9 million shares, or 1.71% of the medical research company's outstanding stock, valued at over $363 million.

Why it matters

Quest Diagnostics is a leading provider of diagnostic information services that support clinical decision-making. As a major shareholder, Dimensional Fund Advisors' increased investment signals confidence in the company's long-term growth prospects within the healthcare industry.

The details

According to a recent 13F filing with the SEC, Dimensional Fund Advisors purchased an additional 6,155 shares of Quest Diagnostics in the third quarter, bringing its total ownership to 1,907,510 shares. This represents a 0.3% increase in the firm's stake in the medical research company.

  • Dimensional Fund Advisors increased its Quest Diagnostics holdings in the 3rd quarter of 2025.

The players

Dimensional Fund Advisors LP

A leading global investment management firm that provides a range of equity, fixed income, and alternative investment strategies to institutional and individual investors worldwide.

Quest Diagnostics Incorporated

A leading provider of diagnostic information services that supports clinical decision-making for patients, physicians, and healthcare organizations.

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The takeaway

Dimensional Fund Advisors' increased stake in Quest Diagnostics reflects the investment firm's confidence in the medical research company's long-term growth potential within the evolving healthcare industry. This development underscores Quest Diagnostics' position as a key player in the diagnostic services market.