Labcorp Holdings Inc.

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 1,007 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

• Registrant confirmed: LABCORP HOLDINGS INC., CIK 0000920148, Delaware, headquartered in Burlington, NC, is the single SEC registrant covering the whole enterprise. Per EDGAR's formerNames field this same CIK previously filed as 'LABORATORY CORP OF AMERICA HOLDINGS' from 1995 to 16 May 2024, when the company completed an internal holding-company reorganization and Labcorp Holdings Inc. became the new public parent (Laboratory Corporation of America Holdings continues to exist as a wholly-owned operating subsidiary, listed without any ownership percentage in Exhibit 21.1 to the FY2025 10-K). There is only one registrant and one CIK to worry about here, unlike the Edison International dual-entity trap the brief warned about: the Q2 2026 10-Q cover page, the FY2025 10-K, and the 2026 DEF 14A all report on Labcorp Holdings Inc. alone, and the share counts and register above all belong to this one entity.
• Holdings side: exactly ONE material equity stake was found, a 15% minority interest in SYNLAB (a European medical-diagnostics group), bought directly from Cinven for approximately $151.6 million, closing 24 March 2025 and held as an equity-method investment. This is the dominant driver of the 'Joint venture partnerships and equity method investments' balance sheet line, which jumped from $16.3m (31 Dec 2024) to $153.9m (31 Dec 2025) and both 10-K and 10-Q attribute the swing in equity-method losses each period 'primarily' to SYNLAB.
• Unlike Quest Diagnostics (the reference file for this project), Labcorp's Exhibit 21.1 to the FY2025 10-K is a PLAIN LIST of subsidiary names with NO ownership percentage disclosed for any entity, and does not name any hospital-system laboratory joint venture at all (no Sonora-Quest-style entities). This was checked deliberately per the brief's instruction to look at Exhibit 21 for percentages the body text lacks, and the answer here is negative: Exhibit 21 gave NO percentages for anything, so it was not used to size or discover any holding. One subsidiary name in the list, 'LabCorp Health System Diagnostics, LLC,' sounds like it could be a hospital-system joint venture, but it is never mentioned anywhere in the 10-K body text and carries no disclosed ownership split from 100%, so no holdings row was created for it; a name alone is not evidence of a minority partner, and inventing an ownership percentage would violate the brief's core rule. It is listed in unknowns instead.
• No named hospital-system laboratory joint ventures (the Quest-style holdings story) were found anywhere in Labcorp's FY2025 10-K or Q2 2026 10-Q body text: searches for 'joint venture', 'hospital', 'health system', 'affiliate', 'Alverno', 'Health Network Laboratories', 'Ascension', 'Vermont' and 'Mount Sinai' returned only generic market-description language (Labcorp's laboratory service contracts and 'partner of choice for health systems' commentary describe ordinary commercial testing/reference-testing relationships, not equity stakes) or no hits at all. Labcorp's 2025 to 2026 deal activity with hospital systems (Empire City Laboratories, Parkview Health System's outreach business, and BioReference Health/Community Health Systems Inc assets in the FY2025 10-K's acquisition note) are asset ACQUISITIONS, not equity-stake investments, and are excluded from holdings per the brief.
• Combined-balance trap, second instance: Labcorp also carries a separate, larger combined balance, 'Investments' in other companies/technology funds developing technology relating to the Company's operations, $201.9m at 31 Dec 2025 ($199.7m at 31 Dec 2024), inside Other assets, net. No individual investee is named anywhere in the 10-K or 10-Q, so per the brief's rule no holdings row was created for it; it is listed in unknowns as an unsized, unnamed bucket.
• Reverse direction, explicitly NOT a Labcorp holding: a small 'Noncontrolling interest put' of $16.4m (30 Jun 2026) / $16.9m (31 Dec 2025) sits on Labcorp's balance sheet, meaning some third party holds a real minority stake in one of Labcorp's own consolidated subsidiaries. Neither the counterparty's name nor the underlying entity nor an ownership percentage is disclosed anywhere found in the 10-K or 10-Q, so this is recorded here as a note only, with no holdings or register row, consistent with the brief's UMass-Memorial-style warning about confusing this direction with a Labcorp-side holding.
• 2023 Fortrea spin-off: on 30 June 2023 Labcorp completed a 100% distribution of Fortrea Holdings Inc. common stock to Labcorp shareholders (treated as a non-taxable dividend in the FY2025 10-K's performance graph). Searches of the FY2025 10-K found no disclosure of any retained equity stake in Fortrea; the Transition Services Agreement between the two companies expired 30 June 2025 and 'all services provided under the TSA terminated on or before the expiration date.' No stake was retained.
• Share basis: company.shares_outstanding (81,100,000) is taken from the Q2 2026 10-Q cover page ('As of August 4, 2026, there were 81.1 million shares...outstanding'), cross-checked against the SEC XBRL dei:EntityCommonStockSharesOutstanding fact (val 81,100,000, same filing) and against stockanalysis.com's 'Shares Out 81.10M'. No stock split was found in the XBRL history checked back through 2024; the steady decline from 83.7 million shares (28 Apr 2025) to 81.1 million (4 Aug 2026) is consistent with ordinary share buybacks, not a split. The DEF 14A's beneficial-ownership table uses a slightly different, earlier count (82,187,046 shares at the 26 Mar 2026 record date), which is used only as the pct_denominator for the two insider rows above (both filed the same day as that count) rather than mixed into the company-level figure.
• Self-gate, computed the way the chart computes it: 9 register rows. Container 'ALL DIRECTORS AND EXECUTIVE OFFICERS AS A GROUP' is reduced to its residual (688,827 minus Schechter's rolled-up 397,154 = 291,673); Schechter counts at full value; the Vanguard family roll-up and every other row (BlackRock, Victory Capital, State Street, Geode, Morgan Stanley, JPMorgan) count at full raw value, since none of them has anything rolling into it. Total: 9,893,237 (Vanguard) + 6,574,261 (BlackRock) + 4,837,573 (Victory Capital) + 3,907,656 (State Street) + 2,188,890 (Geode) + 1,609,447 (Morgan Stanley) + 1,268,384 (JPMorgan) + 397,154 (Schechter) + 291,673 (officer group residual) = 30,968,275 shares against 81,100,000 shares outstanding, or 38.19%, within the expected 25 to 45 percent range.
• Capital Group family (Capital World Investors CIK 0001422849, Capital International Investors CIK 0001562230, Capital Research Global Investors CIK 0001422848) was checked in full against their own Q2 2026 13F-HR information tables and holds ZERO Labcorp shares across all three registrants (no CUSIP 504922105 row in any of the three); no register row is included for this reason. T. Rowe Price was also checked on both registrants per the brief's warning: T. Rowe Price Investment Management, Inc. (CIK 0001897612) holds zero, while T. Rowe Price Associates, Inc. (CIK 0000080255) holds a small position, 119,838 shares (2 information-table lines, values stated in THOUSANDS confirmed by cross-checking implied price per share against Labcorp's own trading range), about 0.15% of the company, well below every other row in this register; it is not included as a row given its size relative to the top 8 to 12 target, but is recorded here so the check is visible.