Builders FirstSource, 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 712 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 side (what Builders FirstSource owns in others) is empty, and this is a sourced finding, not a gap. The newest 10-Q (period 30 Jun 2026, filed 30 Jul 2026, https://www.sec.gov/Archives/edgar/data/1316835/000119312526325451/bldr-20260630.htm) and the 2025 10-K (period 31 Dec 2025, filed 17 Feb 2026, https://www.sec.gov/Archives/edgar/data/1316835/000119312526054643/bldr-20251231.htm) were both searched for 'equity method', 'joint venture', 'unconsolidated', 'non-marketable', 'minority interest', 'Investment in affiliate' and 'noncontrolling'. Only 'equity method' returns a hit, and the same one sentence appears verbatim in both filings: 'The Company's equity investments are accounted for using equity method accounting and are included/recorded in other assets, net in the accompanying Condensed Consolidated Balance Sheets/consolidated balance sheets and are not considered significant to the Company.' No investee is named, no dollar balance is broken out, and no percentage ownership is disclosed anywhere near this sentence in either filing; the amount is folded into 'other assets, net' without a separate line. Per the brief's rule that a combined or unbroken-out balance cannot be assigned to a specific investee, no holding is recorded from this language. Exhibit 21.1 to the 2025 10-K (https://www.sec.gov/Archives/edgar/data/1316835/000119312526054643/bldr-ex21_1.htm) lists 27 subsidiaries by name and state/country of incorporation only, no ownership-percentage column and no name that reads as a joint venture or minority-owned entity; all appear to be wholly owned operating subsidiaries (LLCs and corporations named after acquired building-products distributors such as Alpine Lumber, Kleet Lumber, Spenard Builders Supply). This is the same bare-name-list negative pattern documented for Darden and Labcorp: treated as a genuine negative rather than evidence of looking in the wrong place. The company's 2021 merger with BMC Stock Holdings, Inc. (referenced in this proxy's own director bios, e.g. Dirkson R. Charles served on the BMC Stock Holdings board 2017 to 2021) is a completed stock-for-stock merger resulting in full consolidation, not a joint venture or minority stake, and BMC does not appear as a separate filer or investee anywhere in these filings.
• The former private-equity sponsors, JLL Partners and Warburg Pincus, that historically controlled Builders FirstSource have both fully exited as of the current filings and are recorded here as a note with NO row, per the brief's rule that a completed exit is a note, not a null-shares row. The 2026 DEF 14A (filed 2 Apr 2026, https://www.sec.gov/Archives/edgar/data/1316835/000119312526140509/bldr-20260402.htm) contains zero hits for 'Warburg Pincus' anywhere in the document. 'JLL Partners' appears only inside the board biographies of two directors who are current or former JLL Partners personnel (Paul S. Levy, Founder and Managing Director of JLL Partners since 1988, and Brett N. Milgrim, a former JLL Partners Managing Director 1997 to 2011), describing their employment history, not a JLL Partners fund's current shareholding. The ownership table's own text states explicitly: 'No one person's interest in the Common Stock is more than five percent of the total outstanding Common Stock' beyond Vanguard and BlackRock, both cited there via 13G as passive institutional holders with no PE-sponsor relationship. Mr. Levy's own 1,727,191-share position (1.61% of the company, see his register row) is disclosed with his personal Palm Beach, Florida address, not a JLL Partners office, confirming it is a personal holding rather than a fund position. No JLL Partners or Warburg Pincus entity appears in any Q2 2026 13F, in the current 13G/13G-A filings on EDGAR for this CIK, or in this proxy's ownership table.
• Implied per-share price check: dividing each institution's Q2 2026 13F dollar value by its share count returns approximately $89.3 to $89.5 per share for every filer, all dated 30 Jun 2026: Vanguard's 7 entities, BlackRock, Capital Group's 4 entities, State Street, Wellington, Dimensional, Invesco, Geode and Sands Capital all cluster tightly in that range. This is independently plausible against BLDR's own trading history: the company's stock has fallen substantially since Q2 2026, closing at $72.56 on 19 Aug 2026 (Nasdaq quote API) versus the ~$89.4 implied 30 Jun 2026 price, a roughly 19% decline over about seven weeks, consistent with a cyclical building-products stock in a soft housing market.
• Builders FirstSource has bought back an enormous proportion of its stock, so the share count moves fast and the newest cover page was used throughout: 110,605,069 shares as of 11 Feb 2026 (2025 10-K cover page) fell to 107,596,457 shares as of 23 Jul 2026 (Q2 2026 10-Q cover page, the newest cover-page count found and the one used for shares_outstanding here), a reduction of about 3.0 million shares (2.7%) in roughly five and a half months. The 2026 DEF 14A's own ownership table used an intermediate count, 107,515,372 shares outstanding as of 20 Mar 2026, for its percentage calculations; that older, slightly lower count is preserved unchanged in the two rows sourced to the proxy (the officers/directors aggregate and Paul S. Levy) rather than silently recomputed onto the newer 10-Q denominator, and the resulting small percentage differences from the proxy's own printed figures are called out in each row's method_note.
• T. Rowe Price was swept on both registrants per the brief's instruction and found immaterial: T. Rowe Price Associates, Inc. (CIK 0000080255, Q2 2026 13F-HR filed 14 Aug 2026, values reported in THOUSANDS) holds 167,494 shares (2 lines, $14,988 thousand = $14,988,000, implied price ~$89.5/sh, confirming the thousands scaling), only about 0.16% of the company and well outside the top 8 to 12, so no row is recorded for it. T. Rowe Price Investment Management, Inc. (CIK 0001897612, a separate registrant, 738-row Q2 2026 13F-HR) holds NOTHING in BLDR this quarter: no CUSIP 12008R107 line in its information table. Both checks are genuine, dated findings, not omissions.
• Market cap is computed as the 19 Aug 2026 closing price ($72.56, Nasdaq quote API, market closed at 4:00pm ET that day) times the 23 Jul 2026 10-Q cover-page share count (107,596,457); the two dates are about four weeks apart because no single source carries both a live price and a current share count on the same date. Disclosed rather than treated as precise.
• Self-gate computed from this final file, using the chart's own arithmetic (members at full value, the aggregate reduced only by the members that actually roll into it): 11 register rows. Members map: {'Directors, Director Nominees, and Executive Officers as a group (21 persons)': 1,727,191} (only Paul S. Levy rolls up). Officers/directors aggregate counts at its reduced value, 2,853,638 - 1,727,191 = 1,126,447; every other row, including Levy himself, counts at full value. Sum: Vanguard 11,989,900 + BlackRock 7,833,417 + Capital Group 5,525,993 + State Street 4,839,758 + Wellington 3,465,251 + Dimensional 3,439,279 + Invesco 3,346,367 + Geode 2,834,402 + Sands Capital 2,283,236 + officers/directors aggregate (reduced) 1,126,447 + Paul S. Levy 1,727,191 = 48,411,241 total shares, against shares_outstanding 107,596,457 = 44.99% of the company. This sits at the top of, but inside, the brief's 25% to 45% expected band. No mixed-instrument, mixed-basis or double-counting cause was found: every institutional row is CUSIP 12008R107 common stock at a consistent ~$89.4/sh implied price; the T. Rowe Price thousands convention was caught and rescaled before being excluded as immaterial rather than left in error; and Paul S. Levy's holding is deliberately marked as rolling into the officers/directors aggregate (he is one of its 21 members per the proxy's own table) so it is not double counted.