Quest Diagnostics Incorporated
Ownership
Ownership Structure
Who owns Quest Diagnostics Incorporated (DGX)? This page shows the largest institutions and funds, the ownership structure and the latest insider transactions. 99.2% of the shares are freely tradable; institutional investors hold 97.9%.
Largest Shareholders
Institutions
| Name | Stake (%) | Shares | Change (%) | Date |
|---|---|---|---|---|
| BlackRock Inc | 8.40 | 9,275,411 | +1.1 | 06/30/2026 |
| Vanguard Capital Management, LLC | 6.55 | 7,233,394 | +1.2 | 06/30/2026 |
| Vanguard Portfolio Management, LLC | 5.55 | 6,131,045 | +0.8 | 06/30/2026 |
| State Street Corp | 5.00 | 5,516,643 | +2.5 | 06/30/2026 |
| T. Rowe Price Associates, Inc. | 4.93 | 5,444,986 | -13.5 | 06/30/2026 |
| Boston Partners Global Investors, Inc | 4.30 | 4,744,473 | +18.3 | 06/30/2026 |
| JPMorgan Chase & Co | 3.19 | 3,520,438 | -8.5 | 06/30/2026 |
| Geode Capital Management, LLC | 2.84 | 3,137,873 | +1.7 | 06/30/2026 |
Funds
| Name | Stake (%) | Shares | Change (%) | Date |
|---|---|---|---|---|
| Vanguard MStar Total Stk Mkt Idx Invest | 3.17 | 3,503,384 | -0.4 | 09/30/2026 |
| Vanguard 500 Index Investor | 2.63 | 2,899,231 | -1.4 | 09/30/2026 |
Largest reported positions according to regulatory filings; stake as a percentage of shares outstanding, change versus the previous filing. Source: fundamentals data.
Insider holdings
| Person | Role | Shares | Value | As of | Type |
|---|---|---|---|---|---|
| Davis J. E. | CEO and President | 122,423 | 30,826,111 $ | Sep 1, 2026 | direct |
| Prevoznik Michael E | SVP & General Counsel | 36,557 | 9,205,053 $ | Aug 28, 2026 | direct |
| Samad Sam | Executive Vice President & CFO | 33,568 | 8,452,422 $ | Oct 21, 2026 | direct |
| Pfeiffer Gary M | Director | 29,802 | 7,504,144 $ | Oct 26, 2026 | direct |
| Main Timothy L | Director | 22,478 | 5,659,960 $ | Oct 21, 2026 | direct |
| Gregg Vicky B | Director | 18,449 | 4,645,458 $ | Oct 21, 2026 | direct |
| Plewman Patrick | SVP for Diagnostic Services | 15,334 | 3,861,101 $ | Oct 21, 2026 | direct |
| Kuppusamy Karthik | SVP, Clinical Solutions | 13,619 | 3,429,264 $ | Oct 21, 2026 | direct |
| Delaney Mark E | SVP & Chief Commercial Officer | 10,360 | 2,608,648 $ | Oct 21, 2026 | direct |
| Lassiter Wright III | Director | 10,329 | 2,600,842 $ | Oct 21, 2026 | direct |
| Carter Robert B | Director | 3,874 | 975,473 $ | Oct 21, 2026 | direct |
Holdings as of each person's most recent SEC Form 4 filing — excluding options and RSUs, which are not shares yet. Holdings may have changed between two filings.
Insiders
Insider Transactions
| Date | Person | Role | Type | Shares | Price | Value |
|---|---|---|---|---|---|---|
| Oct 26, 2026 | Pfeiffer Gary M | Director | Sell | 1,203 | 243.00 | 292,329 |
| Oct 21, 2026 | Carter Robert B | Director | Other | 10 | 235.93 | 2,359 |
| Oct 21, 2026 | Samad Sam | Executive Vice President & CFO | Other | 90 | 235.94 | 21,235 |
| Oct 21, 2026 | Gregg Vicky B | Director | Other | 63 | 235.94 | 14,864 |
| Oct 21, 2026 | Kuppusamy Karthik | SVP, Clinical Solutions | Other | 33 | 235.94 | 7,786 |
| Oct 21, 2026 | Lassiter Wright III | Director | Other | 6 | 235.96 | 1,416 |
| Oct 21, 2026 | Plewman Patrick | SVP for Diagnostic Services | Other | 41 | 235.94 | 9,674 |
| Oct 21, 2026 | Main Timothy L | Director | Other | 18 | 235.94 | 4,247 |
| Oct 21, 2026 | Delaney Mark E | SVP & Chief Commercial Officer | Other | 25 | 235.94 | 5,899 |
| Sep 1, 2026 | Davis J. E. | CEO and President | Sell | 10,000 | 242.72 | 2,427,200 |
| Aug 28, 2026 | Prevoznik Michael E | SVP & General Counsel | Other | 1,000 | 0.00 | – |
| Aug 28, 2026 | Prevoznik Michael E | SVP & General Counsel | Sell | 430 | 244.51 | 105,141 |
| Aug 28, 2026 | Prevoznik Michael E | SVP & General Counsel | Sell | 6,237 | 243.63 | 1,519,505 |
| Aug 28, 2026 | Prevoznik Michael E | SVP & General Counsel | Sell | 16,010 | 242.88 | 3,888,437 |
| Aug 28, 2026 | Prevoznik Michael E | SVP & General Counsel | Other | 22,677 | 112.17 | 2,543,679 |
| Jul 28, 2026 | Delaney Mark E | SVP & Chief Commercial Officer | Sell | 1,600 | 235.18 | 376,288 |
| Jul 22, 2026 | Kuppusamy Karthik | SVP, Clinical Solutions | Other | 37 | 206.81 | 7,652 |
| Jul 22, 2026 | Carter Robert B | Director | Other | 11 | 206.80 | 2,275 |
| Jul 22, 2026 | Gregg Vicky B | Director | Other | 72 | 206.81 | 14,890 |
| Jul 22, 2026 | Plewman Patrick | SVP for Diagnostic Services | Other | 46 | 206.81 | 9,513 |
| Jul 22, 2026 | Main Timothy L | Director | Other | 21 | 206.81 | 4,343 |
| Jul 22, 2026 | Samad Sam | Executive Vice President & CFO | Other | 102 | 206.81 | 21,094 |
| Jul 22, 2026 | Lassiter Wright III | Director | Other | 6 | 206.81 | 1,241 |
| Jul 22, 2026 | Delaney Mark E | SVP & Chief Commercial Officer | Other | 34 | 206.81 | 7,031 |
Reportable transactions by officers and major shareholders from SEC Form 4 filings. "Other" includes things like stock grants and option exercises without a buy/sell character. View all insider transactions →
Data as of: October 30, 2026 · Source: fundamental data & SEC filings (annual and quarterly reports, 10-K/10-Q)
Note: pure fact-based analysis, not investment advice and not a solicitation to buy or sell. All figures without guarantee.