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 Materials
Paper & Plastic Packaging Products & Materials0.15%-0.17 ppIndustrial Gases0.51%-0.13 ppSpecialty Chemicals0.41%-0.13 ppConstruction Materials0.25%+0.10 ppGold0.20%+0.07 ppSteel0.16%+0.07 ppCopper0.16%+0.04 ppFertilizers & Agricultural Chemicals0.13%-0.03 ppMetal, Glass & Plastic Containers0.03%-0.01 ppCommodity Chemicals0.04%-0.00 pp
3 · Sub-industry
Inside Construction Materials
Construction Materials · weight
0.25%
Industry change · 12M
+0.10 pp
Construction Materials · contribution
+0.096 pp
Company participation
33%
of industry constituents above their 6M weight average
4 · Companies driving this sub-industry
May 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 |
|---|---|---|---|---|---|---|---|
| CRH plc → CRH | United States | $72.7bn | 0.126% | +0.016 pp | +0.126 pp | +20.2% | No |
| Vulcan Materials Company → VMC | United States | $36.7bn | 0.064% | +0.008 pp | -0.016 pp | +7.5% | Yes |
| Martin Marietta Materials → MLM | United States | $34.9bn | 0.061% | +0.005 pp | -0.014 pp | +6.8% | 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.