Observatory · observe first
Follow the allocation change
Matched S&P 500 members → sector → industry → sub-industry → company. Each step uses the same percentage points.
Historical time machine
Historical observation
20182026
1 · Sector
Weight and 12M allocation change
2 · Industry
Inside Real Estate
Health Care REITs0.34%+0.06 ppTelecom Tower REITs0.27%-0.06 ppData Center REITs0.26%-0.05 ppMulti-Family Residential REITs0.15%-0.05 ppSelf-Storage REITs0.15%-0.04 ppOffice REITs0.04%-0.03 ppReal Estate Services0.15%-0.02 ppRetail REITs0.28%-0.02 ppOther Specialized REITs0.05%-0.01 ppHotel & Resort REITs0.08%-0.01 ppTimber REITs0.04%-0.01 ppIndustrial REITs0.23%-0.01 ppSingle-Family Residential REITs0.03%-0.01 pp
3 · Sub-industry
Inside Telecom Tower REITs
Telecom Tower REITs · weight
0.27%
Industry change · 12M
-0.06 pp
Telecom Tower REITs · contribution
-0.055 pp
Company participation
0%
of industry constituents above their 6M weight average
4 · Companies driving this sub-industry
Jan 2026 · sorted by absolute contribution to 12-month change
| Company | Country | Market cap | Universe weight | 3M contribution | 12M contribution | 12M price return | Above 6M weight average |
|---|---|---|---|---|---|---|---|
| American Tower → AMT | United States | $83.9bn | 0.161% | -0.004 pp | -0.032 pp | +0.3% | No |
| Crown Castle → CCI | United States | $37.8bn | 0.072% | -0.005 pp | -0.014 pp | +2.2% | No |
| SBA Communications → SBAC | United States | $19.6bn | 0.038% | -0.003 pp | -0.010 pp | -4.9% | No |
Company contributions use weights among matched S&P 500 members and add through each level without rescaling. Companies without matched shares and prices are omitted. These observations do not establish official index weights or actual fund flows.