Observatory · observe first
American Tower
AMT · United States · Telecom Tower REITs · matched S&P 500 member. Follow its market-weight contribution.
Historical time machine
Historical observation
20182026
Universe weight
0.123%
12M weight contribution
-0.092 pp
3M weight contribution
-0.044 pp
12M price return
-3.4%
Share of matched S&P 500 members
Monthly observations through Feb 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 |
|---|---|---|---|---|---|
| Feb 2026 | $89.4bn | 0.123% | -0.092 pp | -3.4% | No |
| Jan 2026 | $83.9bn | 0.161% | -0.032 pp | +0.3% | No |
| Dec 2025 | $82.2bn | 0.161% | -0.033 pp | -0.9% | No |
| Nov 2025 | $84.9bn | 0.167% | -0.049 pp | -10.3% | No |
| Oct 2025 | $83.8bn | 0.164% | -0.070 pp | -13.3% | No |
| Sep 2025 | $90.1bn | 0.180% | -0.073 pp | -13.9% | No |
| Aug 2025 | $95.5bn | 0.198% | -0.055 pp | -6.0% | No |
| Jul 2025 | $97.6bn | 0.206% | +0.021 pp | -2.4% | No |
| Jun 2025 | $103.5bn | 0.223% | +0.053 pp | +17.4% | No |
| May 2025 | $100.5bn | 0.228% | +0.053 pp | +13.3% | Yes |
| Apr 2025 | $105.5bn | 0.253% | +0.021 pp | +35.7% | Yes |
| Mar 2025 | $101.7bn | 0.241% | -0.014 pp | +13.9% | Yes |
| Feb 2025 | $96.1bn | 0.215% | -0.051 pp | +6.9% | No |
| Jan 2025 | $86.4bn | 0.192% | -0.079 pp | -2.3% | No |
| Dec 2024 | $85.7bn | 0.194% | -0.106 pp | -12.2% | No |
| Nov 2024 | $97.7bn | 0.216% | -0.088 pp | +3.4% | No |
| Oct 2024 | $99.8bn | 0.235% | -0.048 pp | +23.8% | Yes |
| Sep 2024 | $108.6bn | 0.253% | -0.003 pp | +46.5% | Yes |
| Aug 2024 | $104.7bn | 0.253% | -0.016 pp | +28.0% | Yes |
| Jul 2024 | $102.9bn | 0.185% | -0.009 pp | +20.0% | No |
| Jun 2024 | $90.8bn | 0.170% | -0.039 pp | +3.8% | No |
| May 2024 | $91.4bn | 0.175% | -0.038 pp | +9.9% | No |
| Apr 2024 | $80.1bn | 0.232% | -0.090 pp | -13.1% | No |
| Mar 2024 | $92.1bn | 0.256% | -0.069 pp | -0.0% | No |
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.