Comfort Systems USA, 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 1,180 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 by design, a sourced finding rather than a gap. The latest 10-K (fiscal year ended 31 Dec 2025, filed 19 Feb 2026, https://www.sec.gov/Archives/edgar/data/1035983/000110465926017530/fix-20251231x10k.htm) and the latest 10-Q (quarter ended 30 Jun 2026, filed 23 Jul 2026, https://www.sec.gov/Archives/edgar/data/1035983/000110465926086258/fix-20260630x10q.htm) were both searched via scripts/filing.py search for 'equity method', 'joint venture', 'unconsolidated', 'non-marketable', 'nonmarketable', 'noncontrolling interest', 'investment in', 'affiliate', 'minority interest', 'equity investment', 'variable interest entity', 'VIE' and 'consolidated joint'. Every substantive term returned zero hits in both filings (the 'VIE' hits were all false-positive substring matches inside words like 'review'). The only 'investment in' hits were a small US Treasury bill position ($51.6 million at 30 Jun 2026, $34.4 million at 31 Dec 2025, both held at amortized cost, not an equity stake) and generic risk-factor or cash-flow prose. Comfort Systems is a mechanical and electrical contractor (73.3% mechanical, 26.7% electrical revenue per the 10-K) that grows through outright acquisitions of contracting businesses, which the brief excludes as wholly owned operating subsidiaries. It reports no equity-method investees, no joint ventures (project-specific construction JVs included), no unconsolidated affiliates, no non-marketable equity securities and no VIEs in either filing. This matches the brief's expectation for a roll-up acquirer.
• Construction backlog is not an equity stake. The filings discuss contract backlog extensively as an operating metric, and this was deliberately not treated as a holding: a backlog or contract right is not equity ownership in a counterparty and does not belong in the holdings array.
• No stock split found. Checked the 10-Q and 10-K text for 'split' and 'stock split' (zero hits in the 10-Q; not separately re-checked as a standalone term in the 10-K beyond the same search family) and cross-checked the SEC dei:EntityCommonStockSharesOutstanding cover-page figures across recent quarters: 41,123,365 shares issued less treasury shares of 5,929,036 nets to 35,194,329 at 30 Jun 2026 (10-Q balance sheet basis), consistent in scale with the 35,174,967 shares used by the 1 Mar 2026 proxy and the 35,194,329 shares of the 17 Jul 2026 cover page, a smooth, continuous decline consistent with ongoing buybacks rather than a discontinuous split-driven jump.
• Implied-price check on the high share price, done explicitly because Comfort Systems combines a high share price with a small share count exactly as the brief warns. company.shares_outstanding (35,194,329) times the sourced current share price ($1,751.18 as of 18 Aug 2026, 12:25pm EDT, stockanalysis.com) implies a market cap of about $61.63 billion, which matches stockanalysis.com's own independently reported market cap of $61.53 billion (their small share-count difference, 35.14 million vs 35.194 million, accounts for the small gap) and a separate live-search quote of $1,883.00/share and $66.26 billion market cap from 17 Aug 2026 (a different intraday moment, consistent with a volatile high-beta industrial). Separately, the Q2 2026 13F filings (30 Jun 2026 position date) for BlackRock, FMR, State Street, Geode, Norges Bank, Vanguard's successors and Capital Group all independently imply a per-share price clustered tightly at about $1,980 to $1,985, which is consistent with the 10-K's own disclosure of an all-time-high closing price of $2,065.44 on 22 Jun 2026 followed by a pullback. A four-figure implied price is therefore genuinely correct here, not a values-in-thousands artifact, the same conclusion the AutoZone file reached for its own four-figure share price.
• Vanguard case: PARENT FILED 13F-NT (the same pattern documented in the ross-stores.json reference file for this same quarter). Vanguard Group Inc's parent CIK 0000102909 filed Form 13F-NT for the quarter ended 30 Jun 2026 (filed 13 Aug 2026, accession 0000102909-26-002714), confirmed directly against its own EDGAR submissions feed. Because the parent reports nothing, the register sums the two successor entities that hold FIX for Q2 2026: Vanguard Capital Management LLC (CIK 0002100119, 2,297,509 shares) and Vanguard Portfolio Management LLC (CIK 0002100121, 1,866,170 shares), total 4,163,679 shares, $8,252,203,594. Other, smaller Vanguard-affiliated 13F filers (e.g. Vanguard Advisers Inc, Vanguard Fiduciary Trust Co, Vanguard Global Advisers) were not individually checked; see unknowns.
• Capital Group family: all three mandated entities hold FIX and were summed as a family roll-up (not a proxy aggregate): Capital World Investors (CIK 0001422849) 720,244 shares, Capital International Investors (CIK 0001562230) 141,392 shares, Capital Research Global Investors (CIK 0001422848) 95,976 shares, totaling 957,612 shares, 2.72% of the company, the third-largest active manager after BlackRock and FMR.
• T. Rowe Price: both mandated entities checked. T. Rowe Price Associates, Inc. (CIK 0000080255) holds 324,671 FIX shares as of 30 Jun 2026 (values-in-thousands trap corrected, see the register row's method_note). T. Rowe Price Investment Management, Inc. (CIK 0001897612), the separate registrant named in the brief, filed its own Q2 2026 13F-HR and holds zero FIX shares (CUSIP 199908104 absent from its info table).
• Wellington and other concentrated active managers, checked specifically per the brief's warning that Dodge & Cox, Berkshire and Wellington were previously missed on an industrial by researchers who worked only the usual index-manager checklist. Berkshire Hathaway Inc (CIK 0001067983) Q2 2026 13F-HR: zero FIX shares (CUSIP absent). Dodge & Cox (CIK 0000200217) Q2 2026 13F-HR: zero FIX shares (CUSIP absent). Wellington Management Co LLP (CIK 0001633863) filed 13F-NT for Q2 2026, naming Wellington Management Group LLP (CIK 0000902219) as reporting manager; that entity's 13F-HR shows 104,995 FIX shares (0.30%), included above as a small but sourced position. None of the three surfaced a concentrated Dodge & Cox or Berkshire style holder in FIX; the only sizeable non-index active positions found were FMR (4.72%), Capital Group (2.72%) and T. Rowe Price (0.92%).
• Proxy 5% holders are stale relative to the Q2 2026 13F data used in the register. The 2026 DEF 14A (record date 1 Mar 2026, based on Schedule 13G/13G-A filings as of around that date) lists only three 5%+ holders: The Vanguard Group, Inc. at 12.21% (Schedule 13G/A shared voting 309,812 shares, shared dispositive 4,309,811 shares, filed 30 Jan 2026), BlackRock, Inc. at 8.3% (Schedule 13G/A sole voting 2,749,346 shares, sole dispositive 2,917,000 shares, filed 21 Jan 2026), and FMR LLC at 5.4% (Schedule 13G sole voting 1,878,665.40 shares, sole dispositive 1,892,021.47 shares, filed 11 Nov 2025). The register instead uses each manager's Q2 2026 Form 13F-HR (30 Jun 2026 position date) as the more current, filing-basis source: Vanguard successors sum to 4,163,679 shares (11.83%), BlackRock reports 3,397,683 shares (9.65%), and FMR reports 1,659,799 shares (4.72%), all higher than the proxy's stale Schedule 13G snapshot. Both figures are recorded here; the 13F figures are used as the primary sourced register values.
• Comfort Systems has a single class of common stock and no founder or dual-class control structure: the officers and directors group holds only 1.24% in aggregate, and the largest individual insider is CEO Brian E. Lane at 0.49%, well below any of the top institutional holders. This is not a founder-controlled company in the sense the brief flags for insider emphasis.
• Self-gate, computed the way the chart computes it: 12 register rows. Members rolling into 'All executive officers and directors as a group (17 persons)' are Brian E. Lane (171,523) and Franklin Myers (86,490), summing to 258,013; the aggregate row's own reported 437,025 is reduced to a residual of 179,012. Every other row (Vanguard, BlackRock, FMR, State Street, Geode, Capital Group, Norges Bank, T. Rowe Price, Wellington, and the two member rows at full value) counts at full value. Total = 4,163,679 + 3,397,683 + 1,659,799 + 1,537,139 + 1,151,350 + 957,612 + 471,564 + 324,671 + 104,995 + 171,523 + 86,490 + 179,012 = 14,205,517 shares, or 40.3631% of 35,194,329 shares outstanding, within the expected 25 to 45 percent band.
• Market cap ($61.63bn) is computed as company.shares_outstanding (35,194,329, from the 10-Q cover page, 17 Jul 2026) times the sourced share price ($1,751.18, stockanalysis.com, 18 Aug 2026 intraday). This is close to but not identical to stockanalysis.com's own displayed market cap ($61.53bn), which uses a slightly different, more current share count (about 35.14 million); the discrepancy is fully explained by that difference and is not a data error.