Traces how the Court of Justice defined “every entity engaged in an economic activity, regardless of its legal status and the way in which it is financed” and its limits — solidarity-based social security, exercise of public powers, severable state activities, professional associations, and the single-economic-unit / liability branch (parental presumption from ICI/AEG via Stora/Akzo/Elf/Alliance One/Goldman Sachs, agency in Viho/CEES/CEPSA, succession in ETI/Parker/Skanska, downward liability in Sumal and its limits in MOL, facilitators in AC-Treuhand/ICAP). Earliest case on top, latest on bottom — ordered by exact judgment date. Arrows run from a later case to the earlier case it cites on the undertaking point. Click any case to bold all directly connected cases; use “Full chain” to bold the whole ancestry/descendancy.
Sources: Court of Justice — InfoCuria (curia.europa.eu) and EUR-Lex (eur-lex.europa.eu). Every node links to both its EUR-Lex judgment and its InfoCuria file. Edge labels are the citing paragraphs on the undertaking notion.