The Mosaic Company

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 682 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

• All three unverified leads in the task brief were checked directly against Mosaic's own SEC filings and CONFIRMED, not assumed: (a) the 25% MWSPC interest in Saudi Arabia was real but is now FULLY EXITED, exchanged on 24 Dec 2024 for shares of Ma'aden; (b) the 75% interest in the Miski Mayo phosphate mine in Peru is confirmed and current, consolidated (not equity method); (c) the Ma'aden share exchange has CLOSED (24 Dec 2024, not merely agreed), so it is sized here as a listed-equity holding with a real share count (111,012,433 shares) and a real percentage of Ma'aden (2.86%, using a third-party share count since Ma'aden does not file with the SEC), not left as an unsized JV.
• MWSPC itself no longer exists as a Mosaic holding and is intentionally NOT given a row in this file (a fully exited position is a note, not a row, per project rule); its historical 25% interest and the mechanics of the exchange are preserved in the Ma'aden holding's method_note for context.
• Register self-gate, computed on this final file exactly as the chart computes it (sum raw shares, no member rows exist so no container reduction applies): 11 rows, 155,242,785 shares, 155,242,785 / 317,895,646 = 48.83% of shares outstanding. This sits above the roughly-25%-to-45% band the project brief describes as typical but below the 55% hard-investigate threshold; the concentration is driven by unusually large fresh Q2 2026 positions at BlackRock, AQR Capital and State Street relative to the 31 Mar 2026 register snapshot, all independently verified against each holder's own Q2 2026 13F-HR rather than assumed from the snapshot.
• Every institutional row's implied price (value_usd / shares) clusters tightly around $21.19/share across all 10 fresh Q2 2026 13F rows, which cross-checks internal consistency of the register (T. Rowe's raw filed value was in thousands and was corrected to match this cluster; see that row's method_note).
• Exhibit 21 (FY2025 10-K subsidiary list) was checked for an ownership-percentage column per project technique; it is a bare name list with no percentage column anywhere (a genuine negative), so all ownership percentages in this file (Miski Mayo 75%, Tiplam ~1%, the three equity-method JVs) are sourced to the 10-K body text and Note 9, not to Exhibit 21.
• The three named equity-method investees (River Bend Ag 50.0%, IFC S.A. 45.0%, Canpotex 36.2%) share one COMBINED 'Mosaic's share of equity in net assets' figure of $9.8 million as of 31 Dec 2025 in the FY2025 10-K; per the project's rule this combined figure is NOT assigned to any one of the three, all three carry value_usd: null, and the combined figure is repeated here and in unknowns.
• Both T. Rowe Price registrants (Associates CIK 0000080255 and Investment Management CIK 0001897612) and all known/discoverable Capital Group registrants (six CIKs checked) were verified individually rather than assuming a single CIK represents the family; only one T. Rowe CIK and two of six Capital Group CIKs actually hold Mosaic shares.
• Newest filing check: the Q2 2026 10-Q (filed 5 Aug 2026, period 30 Jun 2026) postdates the FY2025 10-K (filed 27 Feb 2026, period 31 Dec 2025), so the 10-Q was used for shares outstanding and the Ma'aden equity-securities fair value; the 10-K was used for the equity-method ownership percentages and the MWSPC/Ma'aden transaction history, which the 10-Q does not repeat in the same detail.