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
0.114%
12M weight contribution
-0.050 pp
3M weight contribution
-0.003 pp
12M price return
-12.0%
Share of matched S&P 500 members
Monthly observations through Aug 2026
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 |
|---|---|---|---|---|---|
| Aug 2026 | $68.2bn | 0.114% | -0.050 pp | -12.0% | Yes |
| Jul 2026 | $76.5bn | 0.134% | -0.028 pp | +1.8% | Yes |
| Jun 2026 | $70.8bn | 0.123% | -0.043 pp | -6.6% | Yes |
| May 2026 | $67.5bn | 0.117% | -0.065 pp | -14.7% | Yes |
| Apr 2026 | $66.8bn | 0.091% | -0.093 pp | -11.8% | No |
| Mar 2026 | $69.2bn | 0.101% | -0.104 pp | -18.8% | No |
| Feb 2026 | $71.9bn | 0.099% | -0.099 pp | -17.7% | No |
| Jan 2026 | $75.2bn | 0.144% | -0.035 pp | -5.1% | No |
| Dec 2025 | $75.8bn | 0.149% | -0.028 pp | -1.2% | No |
| Nov 2025 | $76.1bn | 0.149% | -0.037 pp | -9.1% | No |
| 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 |
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.