Observatory · observe first
Aon plc
AON · United States · Insurance Brokers · matched S&P 500 member. Follow its market-weight contribution.
Historical time machine
Historical observation
20182026
Universe weight
0.143%
12M weight contribution
-0.043 pp
3M weight contribution
-0.018 pp
12M price return
-6.4%
Share of matched S&P 500 members
Monthly observations through Oct 2025
Company price index
A separate dimension from market allocation
Historical observations
Most recent 24 observations at or before the selected month
| Month | Market cap | Universe weight | 12M weight change | 12M return | Above 6M weight average |
|---|---|---|---|---|---|
| Oct 2025 | $73.2bn | 0.143% | -0.043 pp | -6.4% | No |
| Sep 2025 | $76.9bn | 0.154% | -0.021 pp | +3.9% | No |
| Aug 2025 | $79.1bn | 0.164% | -0.016 pp | +7.6% | No |
| Jul 2025 | $76.7bn | 0.162% | +0.034 pp | +9.1% | No |
| Jun 2025 | $77.0bn | 0.166% | +0.046 pp | +22.5% | No |
| May 2025 | $80.3bn | 0.182% | +0.065 pp | +33.1% | No |
| Apr 2025 | $76.6bn | 0.184% | +0.006 pp | +26.5% | No |
| Mar 2025 | $86.2bn | 0.205% | +0.021 pp | +20.6% | Yes |
| Feb 2025 | $88.4bn | 0.198% | +0.018 pp | +30.5% | Yes |
| Jan 2025 | $80.2bn | 0.178% | +0.001 pp | +25.0% | No |
| Dec 2024 | $77.7bn | 0.176% | +0.002 pp | +24.5% | Yes |
| Nov 2024 | $84.7bn | 0.187% | -0.018 pp | +20.2% | Yes |
| Oct 2024 | $79.3bn | 0.186% | -0.024 pp | +19.4% | Yes |
| Sep 2024 | $75.2bn | 0.175% | -0.045 pp | +7.6% | Yes |
| Aug 2024 | $74.7bn | 0.180% | -0.035 pp | +4.0% | Yes |
| Jul 2024 | $71.4bn | 0.128% | -0.013 pp | +3.8% | No |
| Jun 2024 | $63.8bn | 0.120% | -0.043 pp | -14.2% | No |
| May 2024 | $61.2bn | 0.117% | -0.038 pp | -7.9% | No |
| Apr 2024 | $61.3bn | 0.178% | -0.047 pp | -12.5% | No |
| Mar 2024 | $66.2bn | 0.184% | -0.037 pp | +6.7% | No |
| Feb 2024 | $62.7bn | 0.180% | -0.040 pp | +4.7% | No |
| Jan 2024 | $59.8bn | 0.178% | -0.048 pp | -5.6% | No |
| Dec 2023 | $58.3bn | 0.174% | -0.050 pp | -2.3% | No |
| Nov 2023 | $65.8bn | 0.205% | -0.011 pp | +7.4% | Yes |
Its weight is estimated market cap divided by the total estimated market cap of matched S&P 500 members for the month. This is not an official float-adjusted S&P index weight.