IDEXX Laboratories, 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 1,294 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 empty, a sourced finding rather than a gap. The Q2 2026 10-Q (filed 4 Aug 2026, period ended 30 Jun 2026) and the FY2025 10-K (filed 20 Feb 2026) were both searched for 'equity method', 'unconsolidated', 'joint venture', 'non-marketable equity', 'strategic investment' and 'investment in'. In the 10-Q: 'equity method', 'unconsolidated', 'non-marketable' and 'strategic investment' return zero hits; 'investment in' surfaces one substantive item, described below, plus unrelated hits about net-investment currency hedges and short-term investments. In the 10-K: 'unconsolidated', 'non-marketable equity' and 'strategic investment' return zero hits; 'equity method' appears once, in a boilerplate accounting-policy sentence defining when the equity method would apply (20% to 50% ownership, or 3% to 5% for a limited partnership) with no investee ever named; 'joint venture' appears once, in a Risk Factors sentence about competitors potentially commercializing products 'on their own or through joint ventures', which is about competitors, not an IDEXX joint venture. No individual equity-method investee, joint venture or strategic stake in another company is named or sized in either filing.
• The one substantive item found: the Q2 2026 10-Q's fair value note states IDEXX 'hold[s] an investment in a private equity fund that invests in growth equity and early-stage businesses engaged in pet products and services,' measured using the NAV practical expedient, fair value $3.8 million at 30 Jun 2026 versus $1.8 million at 31 Dec 2025. This is a limited-partnership interest in a diversified fund holding many underlying portfolio companies, not a stake in one named company, so per the brief it is excluded (it is index/fund-style exposure, and even if it were included, no individual underlying investee is sized). The same fund does not appear by this description anywhere in the FY2025 10-K (searched 'NAV practical expedient', 'growth equity', 'pet products and services', 'net asset value', all zero hits there), so its FY2025 year-end disclosure, if any, is worded differently or below the 10-K's disclosure threshold.
• The Q2 2026 10-Q also discloses a $5 million expense for 'the full impairment of an equity investment in the first quarter of the current year' inside the MD&A discussion of G&A expense growth. No investee is named and no ongoing balance is implied (it says 'full impairment'), so nothing is sized or listed as a holding; flagged in unknowns.
• No stock split. Searched the Q2 2026 10-Q for 'stock split', 'forward split' and 'reverse split': all zero hits. Common stock is a single class, $0.10 par value, one vote per share; 108,717 thousand shares issued (statement of stockholders' equity, 30 Jun 2026) net of treasury stock nets to the 78,781,116 shares outstanding on the cover page. Register share counts and shares_outstanding are on a single, non-split-adjusted basis.
• company.shares_outstanding (78,781,116) is taken from the 10-Q cover page, 'was 78,781,116 on July 31, 2026.' stockanalysis.com independently reports 78.78 million shares outstanding and a $43.02 billion market cap at the 17 Aug 2026 close ($546.09/share), consistent with the filed count (78,781,116 x $546.09 implies about $43.02 billion).
• T. Rowe Price thousands-trap check and Vanguard 13F-NT/successor check were both run per the brief; see method_note on each row. Both entities in the T. Rowe family hold IDXX this quarter (unlike some other companies in this project where only one T. Rowe entity holds), so both were rescaled and summed rather than one being reported at zero.
• The 2026 proxy's own 5%-or-greater beneficial owner table (based on stale Schedule 13D/13G filings, cited against 79,518,939 shares outstanding on 8 Mar 2026) shows The Vanguard Group at 9,703,237 shares (12.20%) and BlackRock, Inc. at 7,599,078 shares (9.56%). The register instead uses each manager's Q2 2026 Form 13F-HR/13F-NT filings (30 Jun 2026 position date), more current than the proxy's 13G snapshot: Vanguard's successors sum to 9,048,734 shares (11.49%) and BlackRock to 8,170,178 shares (10.37%), both modestly below the proxy's stale figures, consistent with continued buyback-driven share-count reduction rather than a data error.
• Insiders: no founder, no dual-class structure, no director or officer holds a stake large enough to be individually material. Jonathan J. Mazelsky (President and CEO since 2019, transitioning to Executive Chair after the 12 May 2026 annual meeting, retiring May 2027) is the largest individual holder at 322,720 shares (0.41%), well below any threshold that would make it the 'story' the brief describes for founder/dual-class companies; every other Director and NEO holds well under 60,000 shares. Membership in the 'All Directors and executive officers as of March 8, 2026 as a group (20 persons)' aggregate was decided per the proxy's own table structure (Mazelsky and the group are shown together in the same table with the group total including him), not inferred from holder_type.
• Self-gate, computed the way the chart computes it: 15 register rows (13 institutional 13F rows plus 2 insider rows). Member row (Mazelsky, 322,720 shares) counted at full value; the aggregate group counted at its residual (634,398 minus 322,720 = 311,678). Sum of the 13 institutional rows is 30,114,144 shares; plus Mazelsky's 322,720; plus the aggregate's residual 311,678; total 30,748,542 shares against 78,781,116 shares outstanding, or 39.03%, within the expected 25 to 45 percent range.