Quest Diagnostics Incorporated

The full register, from 13F filings

The Register tab above is hand research: a dozen holders, each traced to the filing it came from. This asks the same question of the whole market for the quarter ended 31-mar-2026, where 1,051 managers reported a position. Broad where the research is deep, and shallow in the ways a 13F always is.

Built from 13F filings, which report US listed, long, US custodied positions only. A register from this source is a floor rather than a level: a holder's true position can be far larger, as BlackRock's ASML stake shows at 1.28m shares in a 13F against 26.3m in its 13G/A. Holdings held through derivatives, outside US custody, or below a manager's reporting obligation do not appear. Where a holder is marked as a family, its total sums several separate filing entities and describes something no single filing describes; the constituent entities and their share counts are listed so the total can be checked. That roll-up can legitimately exceed the family's own Schedule 13G, because a 13G is filed by one legal entity: Vanguard reports Alphabet through ten advisory entities, and The Vanguard Group Inc itself reported zero after its January 2026 disaggregation.

What a reader needs to know to read these numbers

• Holdings are seven private joint ventures with hospital systems and regional partners, all found either in the FY2025 10-K's narrative/Note 20 subsequent events (Corewell Health) or in Exhibit 21.1 to that same 10-K ('Subsidiaries, Joint Ventures and Affiliates'), which was the key source: it lists Quest's exact ownership percentage in each named entity, something the 10-K body text does not do for most of these JVs. This is the JV-heavy company the research brief warned about, so every pct_of_target above was read back against its own method_note prose before writing this file, and none is a fraction (written as 51, 49, 51.0, 53.5, 52.97, never 0.51/0.49/0.535/0.5297).
• Direction matters and was checked row by row per the brief's Nucor/Moody's ICRA precedent. Six of the seven holdings (Corewell Health venture, Diagnostic Laboratory of Oklahoma, Diagnostic Lab of Michigan, Quest Diagnostics Venture LLC, Associated Clinical Laboratories of Pennsylvania LLC, Associated Clinical Laboratories LP) are cases where Quest holds a MAJORITY and, per the 10-K's own statement that Quest 'typically' has majority ownership or day-to-day management of its JVs, likely CONSOLIDATES them; these are still forward Quest holdings at Quest's own stated percentage, per the brief's rule, not reclassified as noncontrolling interests. Only Sonora Quest Laboratories LLC (49%) is a genuine minority, equity-method holding.
• REVERSE DIRECTION, explicitly NOT a Quest holding: UMass Memorial Medical Center holds an 18.9% redeemable noncontrolling interest in Quest Diagnostics Massachusetts LLC (Quest holds the other 81.1%, confirmed in Exhibit 21.1), sold to UMass in July 2015; UMass has the right to require Quest to buy back its interest at fair value, and the balance ($80 million at both 31 Dec 2025 and 30 Jun 2026) sits in 'Redeemable noncontrolling interest' on Quest's balance sheet, outside stockholders' equity. This is a hospital partner's minority stake IN a Quest subsidiary, the reverse direction from the six consolidated JV holdings above, and is recorded here as a note only, with no register or holdings row, per the brief's explicit warning about this exact confusion.
• Combined-balance trap: Sonora Quest Laboratories LLC (the probable identity of the unnamed 'diagnostic information services joint venture' in the equity method investees note) and an unnamed 'investment in a fund that purchases strategic holdings in private companies in the healthcare industry' share a single 'Investments in equity method investees' balance sheet line: $136 million at 31 Dec 2025, $137 million at 30 Jun 2026. Neither the 10-K nor the Q2 2026 10-Q splits this by investee, so per the brief's rule both get value_usd: null; the fund itself is not named anywhere found, so it does not appear as its own holdings row (a name was not invented for it), and is listed in unknowns instead.
• The Corewell Health venture is the one holding with a modelled value_usd ($263,326,531), derived from the Q2 2026 10-Q's disclosure that the 49% noncontrolling interest transferred to Corewell Health was valued at $253 million at formation (Jan 2026); this is flagged basis: filed_10q / confidence: estimated because the $263M figure for Quest's 51% is arithmetic (253M / 0.49 x 0.51), not a number the filing states directly.
• Quest's own risk-factor language ('joint venture arrangements with leading hospitals and health systems... provide diagnostic information services') and the 10-K's 'Physician lab services' and 'Hospital lab services' revenue-mix disclosures describe ordinary laboratory service contracts and reference-testing agreements with hospitals and health systems generally; these are commercial contracts, not equity stakes, and are excluded from holdings per the brief.
• Register: no dual-class structure (single class of common stock) and no founder/control story; Chairman/CEO/President James E. Davis's beneficial ownership (489,497 shares, 0.44%) is small and there is no other outsized insider or sovereign-adjacent position beyond Norges Bank's ordinary 13F stake.
• Capital Group family (Capital World Investors CIK 0001422849, Capital International Investors CIK 0001562230, Capital Research Global Investors CIK 0001422848) was checked in full for Q2 2026 and holds ZERO Quest Diagnostics shares across all three registrants (no CUSIP 74834L100 row in any of the three 13F-HR info tables); no register row is included for this reason, consistent with the brief's example of a family that must be checked in full even when the answer turns out to be zero.
• Self-gate, computed the way the chart computes it (per scripts described in the research-chunk-prompt): 10 register rows; the officer/director aggregate is reduced to its residual (975,609 minus James E. Davis's 489,497 rolled-up shares = 486,112) and Davis is counted at full value; all other rows (Vanguard family roll-up, BlackRock, State Street, T. Rowe Price, JPMorgan, Geode, Morgan Stanley, Norges Bank) count at full raw value. Total: 14,553,517 (Vanguard) + 9,275,411 (BlackRock) + 5,516,643 (State Street) + 5,444,986 (T. Rowe Price) + 3,520,438 (JPMorgan) + 3,137,873 (Geode) + 2,460,497 (Morgan Stanley) + 1,406,620 (Norges Bank) + 489,497 (Davis) + 486,112 (officer group residual) = 46,291,594 shares against 110,373,360 shares outstanding, or 41.94%, within the expected 25 to 45 percent range.