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 & Materials27.67%+27.31 ppIndustrial Gases0.43%-0.25 ppSpecialty Chemicals0.36%-0.20 ppConstruction Materials0.21%+0.06 ppGold0.17%+0.04 ppFertilizers & Agricultural Chemicals0.12%-0.03 ppSteel0.09%-0.02 ppCommodity Chemicals0.04%-0.01 ppMetal, Glass & Plastic Containers0.02%-0.01 ppCopper0.12%-0.01 pp
3 · Sub-industry
Inside Construction Materials
Construction Materials · weight
0.21%
Industry change · 12M
+0.06 pp
Construction Materials · contribution
+0.063 pp
Company participation
33%
of industry constituents above their 6M weight average
4 · Companies driving this sub-industry
Mar 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 | $70.2bn | 0.102% | -0.062 pp | +0.102 pp | +20.4% | Yes |
| Vulcan Materials Company → VMC | United States | $35.6bn | 0.052% | -0.022 pp | -0.021 pp | +17.5% | No |
| Martin Marietta Materials → MLM | United States | $35.5bn | 0.052% | -0.022 pp | -0.018 pp | +23.8% | 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.