Aon plc

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 1,230 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

• Share instrument. Aon plc is incorporated in Ireland and its listed equity is called 'Class A Ordinary Shares', $0.01 nominal value, trading on NYSE as AON, per the 2026 10-Q cover page and the 10-K's 'Risks Related to Being an Irish-incorporated Company' section. There is no common stock in the traditional US sense. The 10-K and 10-Q were searched for 'redomicil' and 'scheme of arrangement' and returned no hits; the only major domicile history on record in these filings is Aon's move to Irish incorporation in 2020 in connection with the since-terminated Willis Towers Watson combination (the WTW deal itself was terminated in 2021, but the Irish plc structure it created was retained). No further reclassification or share-basis discontinuity was found across the filings reviewed, so shares_outstanding and every register row sit on one consistent Class A Ordinary Shares basis.
• Outstanding, not issued. shares_outstanding (212,125,434) is taken directly from the Q2 2026 10-Q cover page, which states 'Number of class A ordinary shares of Aon plc, $0.01 nominal value, outstanding as of July 28, 2026: 212,125,434'. This is explicitly the outstanding count, not the issued count, so it already excludes any shares Aon holds in treasury (Aon has repurchased 178.3 million shares cumulatively for approximately $27.3 billion per the same 10-Q, but the cover-page figure is post-repurchase outstanding). All register percentages use this same outstanding figure as denominator.
• Fiduciary and client funds excluded. As an insurance broker, Aon's balance sheet carries Fiduciary assets of $20,698 million (30 Jun 2026) matched by an equal Fiduciary liabilities balance, representing premiums and claims held on behalf of insurers and clients pending remittance. Per the brief's treatment of PNC, Ameriprise and T. Rowe Price, these are client-held funds, not Aon's own equity holdings, and are excluded from holdings entirely. Aon does not itself file a Form 13F (its business is brokerage and consulting, not asset management on a discretionary basis), so unlike Ameriprise there is no separate 13F filing of Aon's own to exclude.
• Holdings side is empty by design, a sourced finding rather than a gap. The FY2025 10-K and Q2 2026 10-Q were both searched for 'equity method', 'unconsolidated', 'joint venture', 'strategic investment', 'non-marketable equity', 'Aon owns' and 'noncontrolling interest'. 'Equity method', 'unconsolidated', 'strategic investment' and 'joint venture' (in a financial-holding sense) return zero hits in either filing; the sole 'joint venture' hit in the 10-K is a risk-factor reference to operational risk in managing overseas joint venture operations generally, not a named investment. 'Noncontrolling interest' appears extensively (33 hits in the 10-K) but exclusively describes third parties' minority stakes IN Aon's own majority-owned, consolidated subsidiaries (arising mainly from the April 2024 NFP acquisition, which brought in 'certain less-than-wholly owned entities'), the reverse direction from a holding Aon owns in someone else. No individual noncontrolling-interest entity is named or separately sized in either filing; the 10-K only discloses aggregate fair values of $108 million (redeemable) and $85 million (nonredeemable) NCI recognized at the NFP acquisition date. Per the rule against assigning a combined, unnamed balance to a specific investee, none of this became a holdings row; the fact and the combined figures are recorded here and in unknowns instead. All named Aon entities encountered (Columbia-style equivalents do not apply here; NFP, CoverWright, and the various regional Aon subsidiaries) are wholly owned or majority-consolidated operating subsidiaries, correctly excluded per the brief.
• Aon has a single listed class, Class A Ordinary Shares, one vote per share; no dual-class or founder-control structure. CEO Gregory C. Case has led Aon since 2005 but the 2026 proxy states his and the full 20-person officer/director group's beneficial ownership are both under 1 to 1.1% of outstanding shares; there is no insider-control story here comparable to a founder-led company.
• Register cross-check against the proxy's own 5%-owner table. The 2026 proxy's 'Principal Holders of Voting Securities' table (sourced from stale Schedule 13G/13G-A filings) shows only two 5%+ holders: BlackRock, Inc. at 13,428,205 shares (6.29%, as of 31 Dec 2024 per 13G/A filed 5 Feb 2025) and Capital World Investors at 12,142,251 shares (5.69%, per its own 13G). The register instead uses each manager's Q2 2026 Form 13F-HR (30 Jun 2026 position date), which is more current: BlackRock 15,716,429 shares (7.41%) and the full Capital Group family 12,505,639 shares (5.89%). Both institutional totals are higher under the fresher 13F data, consistent with continued accumulation over 2025 to 2026 rather than a data error; the 13F figures are used as the primary sourced numbers throughout.
• T. Rowe Price implied-price cross-check. Aon's actual closing price on 30 Jun 2026 was $331.69 (stockanalysis.com daily history), and the rescaled T. Rowe Price Associates figure implies $331.66/share, an almost exact match confirming the thousands-convention rescale is correct. Other Q2 2026 13F filers on the same CUSIP imply prices from $327.60 (JPMorgan) to $338.20 (MFS) on the same date, a normal spread for a quarter with intraquarter trading and differing valuation timestamps.
• Self-gate check, computed exactly as specified: 16 register rows. Raw shares summed per the formula (institutional and non-container insider rows at full value, the 'All directors and executive officers as a group' row reduced to its residual of 522,275 = 2,144,049 minus Gregory C. Case's 1,621,774) totals 103,280,717 shares against 212,125,434 shares outstanding, or 48.69%. This sits above the tight 25 to 45% expectation but within the explicit 15 to 55% tolerance band; it is plausible rather than a defect because Aon has repurchased 178.3 million shares cumulatively (about $27.3 billion), which concentrates institutional ownership as a share of a shrinking float. No instrument-basis, split, or double-counting issue was found on review of every row.
• Market capitalisation of $73.73 billion and the $343.20 share price are stockanalysis.com's intraday figures as of 18 Aug 2026, 11:51 AM EDT (market open), sourced separately from the 30 Jun 2026 closing price of $331.69 used for the T. Rowe Price cross-check and from the 28 Jul 2026 shares-outstanding figure used for all register percentages; 212,125,434 shares x $343.20 implies approximately $72.8 billion, reasonably close to the reported $73.73 billion given the market-cap figure may use a marginally different, more current share count.