Quest Diagnostics's three largest insider shareholders as of September 12, 2026 are Stephen H Rusckowski (Chairman, Ceo And President, 389.60K shares), J. E. Davis (Ceo And President, 122.42K shares), Mark Guinan (Executive Vice President Cfo, 98.98K shares).
| # | Insider | Position | Direct | Indirect | Total | Share of Insiders | Last Filed |
|---|---|---|---|---|---|---|---|
| 1 | Stephen H Rusckowski | Chairman, Ceo And President | 389,597 | 0 | 389,597 | 37.5% | 08 Mar, 2023 |
| 2 | J. E. Davis | Ceo And President | 122,423 | 0 | 122,423 | 11.8% | 03 Sep, 2026 |
| 3 | Mark Guinan | Executive Vice President Cfo | 98,981 | 0 | 98,981 | 9.5% | 09 Mar, 2022 |
| 4 | Catherine T. Doherty | Evp, Regional Businesses | 67,122 | 0 | 67,122 | 6.5% | 06 Mar, 2026 |
| 5 | Manner Carrie Eglinton | Svp, Advanced Diagnostics | 48,391 | 0 | 48,391 | 4.7% | 09 Mar, 2022 |
| 6 | Michael E Prevoznik | Svp General Counsel | 36,557 | 0 | 36,557 | 3.5% | 31 Aug, 2026 |
| 7 | Michael J Deppe | Svp, Corp. Controller Cao | 35,196 | 0 | 35,196 | 3.4% | 06 Mar, 2026 |
| 8 | Sam Samad | Executive Vice President Cfo | 33,478 | 0 | 33,478 | 3.2% | 27 Jul, 2026 |
| 9 | Timothy M Ring | Director | 31,140 | 0 | 31,140 | 3.0% | 21 May, 2026 |
| 10 | Gary M Pfeiffer | Director | 31,005 | 0 | 31,005 | 3.0% | 21 May, 2026 |
| 11 | Timothy L Main | Director | 22,460 | 0 | 22,460 | 2.2% | 27 Jul, 2026 |
| 12 | Gail R Wilensky | Director | 20,506 | 0 | 20,506 | 2.0% | 19 May, 2023 |
| 13 | Vicky B Gregg | Director | 18,386 | 0 | 18,386 | 1.8% | 27 Jul, 2026 |
| 14 | Patrick Plewman | Svp For Diagnostic Services | 15,293 | 0 | 15,293 | 1.5% | 27 Jul, 2026 |
| 15 | Karthik Kuppusamy | Svp, Clinical Solutions | 13,557 | 0 | 13,557 | 1.3% | 27 Jul, 2026 |
| 16 | Denise M Morrison | Director | 11,929 | 0 | 11,929 | 1.1% | 21 May, 2026 |
| 17 | Mark E Delaney | Svp Chief Commercial Officer | 10,335 | 0 | 10,335 | 1.0% | 29 Jul, 2026 |
| 18 | Wright Iii Lassiter | Director | 10,323 | 0 | 10,323 | 1.0% | 27 Jul, 2026 |
| 19 | Tracey Doi | Director | 7,748 | 0 | 7,748 | 0.7% | 21 May, 2026 |
| 20 | Luis Diaz | Director | 5,196 | 0 | 5,196 | 0.5% | 21 May, 2026 |
| 21 | Mark A Gardner | Svp Of Molecular Gen Oncol | 4,673 | 0 | 4,673 | 0.4% | 26 Sep, 2024 |
| 22 | Robert B Carter | Director | 3,864 | 0 | 3,864 | 0.4% | 27 Jul, 2026 |
| 23 | Timothy C Wentworth | Director | 1,358 | 0 | 1,358 | 0.1% | 21 May, 2026 |
Each row is that insider’s most recently reported position, from Form 4 filings over the last 60 months — which is why this total does not tie to the quarterly series above, where a quarter counts only the insiders who filed in it. Shares held through a fund or institutional portfolio are counted on the institutional ownership page instead.
| Date | Insider | Position | Transaction | Shares | Price | Value | Shares Held After | Ownership |
|---|---|---|---|---|---|---|---|---|
| 01 Sep, 2026 | J. E. Davis | Ceo And President | Disposed S | 10,000 | $242.72 | $2.43Mn | 122,423 | Direct |
| 28 Aug, 2026 | Michael E Prevoznik | Svp General Counsel | Acquired M | 22,677 | $112.17 | $2.54Mn | 60,234 | Direct |
| 28 Aug, 2026 | Michael E Prevoznik | Svp General Counsel | Disposed S | 16,010 | $242.88 | $3.89Mn | 44,224 | Direct |
| 28 Aug, 2026 | Michael E Prevoznik | Svp General Counsel | Disposed S | 6,237 | $243.63 | $1.52Mn | 37,987 | Direct |
| 28 Aug, 2026 | Michael E Prevoznik | Svp General Counsel | Disposed S | 430 | $244.51 | $105.14K | 37,557 | Direct |
| 28 Aug, 2026 | Michael E Prevoznik | Svp General Counsel | Disposed G | 1,000 | $0.00 | $0 | 36,557 | Direct |
| 28 Aug, 2026 | Michael E Prevoznik | Svp General Counsel | Disposed M | 22,677 | $112.17 | $2.54Mn | 0 | Direct |
| 28 Jul, 2026 | Mark E Delaney | Svp Chief Commercial Officer | Disposed S | 1,600 | $235.18 | $376.29K | 10,335 | Direct |
| 22 Jul, 2026 | Vicky B Gregg | Director | Acquired A | 72 | $206.81 | $14.89K | 18,386 | Direct |
| 22 Jul, 2026 | Wright Iii Lassiter | Director | Acquired L | 6 | $206.81 | $1.24K | 10,323 | Direct |
| 22 Jul, 2026 | Timothy L Main | Director | Acquired L | 21 | $206.81 | $4.34K | 22,460 | Direct |
| 22 Jul, 2026 | Patrick Plewman | Svp For Diagnostic Services | Acquired L | 46 | $206.81 | $9.51K | 15,293 | Direct |
| 22 Jul, 2026 | Sam Samad | Executive Vice President Cfo | Acquired A | 102 | $206.81 | $21.09K | 33,478 | Direct |
| 22 Jul, 2026 | Karthik Kuppusamy | Svp, Clinical Solutions | Acquired L | 37 | $206.81 | $7.65K | 13,557 | Direct |
| 22 Jul, 2026 | Mark E Delaney | Svp Chief Commercial Officer | Acquired L | 34 | $206.81 | $7.03K | 11,935 | Direct |
| 22 Jul, 2026 | Robert B Carter | Director | Acquired L | 11 | $206.80 | $2.27K | 3,864 | Direct |
| 01 Jul, 2026 | Timothy C Wentworth | Director | Acquired A | 144 | $0.00 | $0 | 342 | Direct |
| 04 Jun, 2026 | Karthik Kuppusamy | Svp, Clinical Solutions | Acquired M | 3,320 | $127.73 | $424.05K | 16,830 | Direct |
| 04 Jun, 2026 | Karthik Kuppusamy | Svp, Clinical Solutions | Acquired M | 4,827 | $121.81 | $587.95K | 21,657 | Direct |
| 04 Jun, 2026 | Karthik Kuppusamy | Svp, Clinical Solutions | Disposed S | 8,147 | $200.00 | $1.63Mn | 13,510 | Direct |