AON
Aon PLC
Aon PLC historical holders
total: 18
Cantillon Capital Management Aon PLC transactions over time
- Total transactions:
- 38
- New positions:
- 1
- Added:
- 10
- Reduced:
- 27
- Held since:
- 2016 Q4
- Held for:
- 38 quarters
- Latest activity:
- 2026 Q1
William Von Mueffling has been an institutional investor in Aon PLC (AON) since 2016 Q4. According to 2026 Q1 report, William Von Mueffling holds 1,095,574 shares with a market value of roughly $353.63M representing 2.35% of their equity portfolio. The fund/company first acquired AON in 2016 Q4, initially purchasing 516,406 shares. Since the initial investment, Cantillon Capital Management has made 37 more transactions in this position.
Does William Von Mueffling still hold AON?
Yes, William Von Mueffling continues to hold Aon PLC (AON). According to their 2026 Q1 report, they maintain a position of 1,095,574 shares valued at approximately $353.63M, representing 2.35% of their equity portfolio.
When did William Von Mueffling first invest in AON?
William Von Mueffling first invested in Aon PLC (AON) in 2016 Q4 at the reported quarter-end price of $111.53 per share, acquiring 516,406 shares in their initial purchase.
What is William Von Mueffling's average cost basis for AON?
Based on historical transaction data, William Von Mueffling's estimated cost basis for Aon PLC (AON) is approximately $159.64 per share. This represents their average reported price* across all buy transactions.
Estimated cost basis*
- Weighted AVG buy price:
- $159.64
- Weighted AVG sell price:
- $255.01
AON transactions history by Cantillon Capital Management
38 results
| Period |
% of portfolio |
Shares held after* |
Reported price* |
Value* |
% (shares) of activity |
% change to portfolio |
|---|---|---|---|---|---|---|
|
2026 Q1
|
2.35%
|
1,095,574
|
$322.78
|
$353,629,376
|
-11.86% (-147,444)
|
-0.26%
|
|
2025 Q4
|
2.37%
|
1,243,018
|
$352.88
|
$438,636,192
|
+0.75% (+9,277)
|
+0.02%
|
|
2025 Q3
|
2.42%
|
1,233,741
|
$356.58
|
$439,927,366
|
-1.09% (-13,613)
|
-0.03%
|
|
2025 Q2
|
2.57%
|
1,247,354
|
$356.76
|
$445,006,013
|
-2.82% (-36,194)
|
-0.08%
|
|
2025 Q1
|
3.32%
|
1,283,548
|
$399.09
|
$512,251,171
|
-3.00% (-39,680)
|
-0.1%
|
|
2024 Q4
|
2.87%
|
1,323,228
|
$359.16
|
$475,250,568
|
+0.53% (+7,010)
|
+0.02%
|
|
2024 Q3
|
2.78%
|
1,316,218
|
$345.99
|
$455,398,266
|
+15.63% (+177,956)
|
+0.38%
|
|
2024 Q2
|
2.23%
|
1,138,262
|
$293.58
|
$334,170,958
|
-4.84% (-57,928)
|
-0.11%
|
|
2024 Q1
|
2.51%
|
1,196,190
|
$333.72
|
$399,192,527
|
-1.97% (-23,984)
|
-0.05%
|
|
2023 Q4
|
2.37%
|
1,220,174
|
$291.02
|
$355,095,037
|
-2.38% (-29,793)
|
-0.06%
|
|
2023 Q3
|
3.01%
|
$324.22
|
-0.39% (-4,881)
|
|||
|
2023 Q2
|
3.03%
|
$345.20
|
+6.35% (+74,932)
|
|||
|
2023 Q1
|
3.03%
|
$315.29
|
-1.72% (-20,670)
|
|||
|
2022 Q4
|
3.05%
|
$300.14
|
-1.75% (-21,328)
|
|||
|
2022 Q3
|
2.96%
|
$267.87
|
-0.93% (-11,477)
|
|||
|
2022 Q2
|
2.78%
|
$269.68
|
-0.53% (-6,609)
|
|||
|
2022 Q1
|
2.88%
|
$325.63
|
+2.98% (+35,910)
|
|||
|
2021 Q4
|
2.39%
|
$300.56
|
-6.89% (-89,052)
|
|||
|
2021 Q3
|
2.52%
|
$285.77
|
-1.77% (-23,289)
|
|||
|
2021 Q2
|
2.12%
|
$238.76
|
-1.54% (-20,543)
|
|||
|
2021 Q1
|
2.24%
|
$230.11
|
-3.58% (-49,605)
|
|||
|
2020 Q4
|
2.20%
|
$211.27
|
-0.65% (-9,090)
|
|||
|
2020 Q3
|
2.41%
|
$206.30
|
-1.13% (-15,963)
|
|||
|
2020 Q2
|
2.36%
|
$192.60
|
+0.96% (+13,457)
|
|||
|
2020 Q1
|
2.55%
|
$165.04
|
-0.09% (-1,197)
|
|||
|
2019 Q4
|
2.71%
|
$208.29
|
-2.08% (-29,679)
|
|||
|
2019 Q3
|
2.69%
|
$193.57
|
-0.61% (-8,783)
|
|||
|
2019 Q2
|
2.80%
|
$192.98
|
-2.14% (-31,497)
|
|||
|
2019 Q1
|
2.67%
|
$170.70
|
+11.28% (+148,883)
|
|||
|
2018 Q4
|
2.32%
|
$145.36
|
+0.78% (+10,166)
|
|||
|
2018 Q3
|
2.27%
|
$153.78
|
-6.25% (-87,408)
|
|||
|
2018 Q2
|
2.06%
|
$137.17
|
+53.23% (+485,561)
|
|||
|
2018 Q1
|
1.45%
|
$140.33
|
-1.86% (-17,277)
|
|||
|
2017 Q4
|
1.48%
|
$134.00
|
-6.43% (-63,868)
|
|||
|
2017 Q3
|
1.69%
|
$146.10
|
-2.74% (-27,986)
|
|||
|
2017 Q2
|
1.70%
|
$132.95
|
-4.00% (-42,580)
|
|||
|
2017 Q1
|
1.61%
|
$118.69
|
+106.01% (+547,434)
|
|||
|
2016 Q4
|
0.81%
|
$111.53
|
new
|
|||
* Shares, change to shares, sold shares, shares held after: split-adjusted.
* Reported price: this doesn't represent the actual buy or sell price. It is the split-adjusted price of the security as of the last day of the reported period.
If the security is completely sold out, we show the reported split-adjusted price prior to the actual period.
If the security is completely sold out, we show the reported split-adjusted price prior to the actual period.
* Estimated cost basis: based on "Reported price*" (not earlier than 2013 Q2). Calculation starts from the latest "new buy" activity to the latest "close out" activity (if any).
* Value or Price: If the security is completely sold out, we show the reported value (or price) prior to the actual period.
* New buy or own: this means there is no earlier reporting (for us or in general). So we can't know if the actual purchase of the security happened at the reported period or earlier.