Aon plc
DE ˙ DB ˙ IE00BLP1HW54
276,10 € ↑5,50 (2,03%)
2026-06-05
DEL PRIS
SecurityDE:4VK / Aon plc
InstitutionMattern Capital Management, Llc
Latest Disclosed Ownership4,116 shares
Latest Disclosed Value $ 1,328,562
Mattern Capital Management, Llc reports 3.57% increase in ownership of 4VK / Aon plc

On May 4, 2026 - Mattern Capital Management, Llc filed a 13F-HR form disclosing ownership of 4,116 shares of Aon plc (DE:4VK) valued at $1,152,892 USD as of March 31, 2026. The entity filed a previous 13F-HR on January 29, 2026 disclosing 3,974 shares of Aon plc. This represents a change in shares of 3.57% during the quarter. The current value of the position is $1,136,428 USD.

Institutional Ownership: 13F and NPORT Filings

The Security and Class in the table below are shown exactly as filed by the investor. We do our best to track continuity of investments through acquisitions, and this will be reflected in the table as changes in names. In addition to descriptive data, performance of the investment is shown over time. To calculate quarterly performance, we first calculate cost basis of the shares purchased during the quarter, then use that to calculate gross profit. Quarterly return is Gross Profit / Starting Portfolio value.

Note that cost basis is calculated and stored in thousands, so small quarterly changes in shares frequently result in a cost basis of zero.

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Disclosed Equity Positions (from 13F/NPORT Filings)
File
Date		 Effective
Date		Form Security Class ID Avg Price
Paid (Est)		 Reported
Shares		 ΔShares ΔShares
(%)		 Reported
Value
(x1000)		 ΔValue
(%)		 Alloc
(%)		 ΔAlloc ΔAlloc (%) Cost Basis
(x1000)		 Unrealized
Gain/Loss
(x1000)
2026-05-04 2026-03-31 13F AON SHS CL A G0403H108 4,116 142 3.57 1,329 -5.28 0.1591
2026-01-29 2025-12-31 13F AON SHS CL A G0403H108 3,974 33 0.84 1,402 -0.21 0.1656
2025-10-21 2025-09-30 13F AON SHS CL A G0403H108 3,941 704 21.75 1,405 21.75 0.1652
2025-07-21 2025-06-30 13F AON SHS CL A G0403H108 3,237 358 12.43 1,155 0.52 0.1387
2025-04-23 2025-03-31 13F AON SHS CL A G0403H108 2,879 155 5.69 1,149 17.38 0.1463
2025-02-03 2024-12-31 13F AON SHS CL A G0403H108 2,724 77 2.91 978 6.89 0.1275
2024-10-24 2024-09-30 13F AON SHS CL A G0403H108 2,647 169 6.82 916 25.86 0.1153
2024-08-02 2024-06-30 13F AON SHS CL A G0403H108 2,478 337 15.74 727 1.82 0.1005
2024-05-14 2024-03-31 13F AON SHS CL A G0403H108 2,141 971 82.99 714 110.00 0.0970
2024-02-14 2023-12-31 13F AON SHS CL A G0403H108 1,170 0 0.00 340 -10.29 0.0495
2023-11-08 2023-09-30 13F AON SHS CL A G0403H108 1,170 0 0.00 379 -5.96 0.0614
2023-08-08 2023-06-30 13F AON SHS CL A G0403H108 1,170 0 0.00 404 9.51 0.0656
2023-05-12 2023-03-31 13F AON SHS CL A G0403H108 1,170 0 0.00 369 4.84 0.0651
2023-02-06 2022-12-31 13F AON SHS CL A G0403H108 1,170 0 0.00 351 12.14 0.0649
2022-11-08 2022-09-30 13F AON SHS CL A G0403H108 1,170 0 0.00 313 -0.95 0.0652
2022-08-08 2022-06-30 13F AON SHS CL A G0403H108 1,170 0 0.00 316 -17.06 0.0625
2022-05-03 2022-03-31 13F AON SHS CL A G0403H108 1,170 0 0.00 381 8.24 0.0681
2022-02-03 2021-12-31 13F AON SHS CL A G0403H108 1,170 0 0.00 352 5.39 0.0616
2021-11-01 2021-09-30 13F AON SHS CL A G0403H108 1,170 -193 -14.16 334 2.77 0.0659
2021-08-03 2021-06-30 13F AON SHS CL A G0403H108 1,363 0 0.00 325 3.50 0.0643
2021-05-17 2021-03-31 13F AON SHS CL A G0403H108 1,363 0 0.00 314 9.03 0.0679
2021-02-03 2020-12-31 13F AON SHS CL A G0403H108 1,363 0 0.00 288 2.49 0.0690
2020-11-16 2020-09-30 13F AON SHS CL A G0403H108 1,363 0 0.00 281 6.84 0.0734
2020-08-07 2020-06-30 13F AON SHS CL A G0403H108 1,363 0 0.00 263 16.89 0.0763
2020-05-11 2020-03-31 13F AON SHS CL A G0408V102 1,363 0 0.00 225 -20.77 0.0766
2020-02-13 2019-12-31 13F AON SHS CL A G0408V102 1,363 1,363 284 0.0786
Legend
Shares
The total number of shares held by the institution at the end of the reporting period (the effective date). This is provided in the filing.
Value
The total value of the shares as of the effective date. This is provided in the filing.
Avg. Share Price
The weighted average share price of the shares held by the institution. We use FIFO accounting to determine this price
Class
This is the security class as indicated by the filer. There are a variety of values for this field. Common values include "EC" = equity common, "EP" - equity preferred
Allocation (%)
The percent of the institution's portfolio that this position represents. This is provided in NPORT filings. For 13F filings, we calculate it.
Change in Allocation
The change in allocation from the prior reporting period. This is calculated as current allocation - prior allocation.
Change in Allocation (%)
The percent change in allocation from the prior reporting period. This is calculated as (current allocation - prior allocation) / prior allocation.
Cost Basis
The total cost of the shares held. This is calculated as reported shares * avg. share price
Unrealized Gain/Loss
This is the market value of the position as of the effective date minus the cost basis.