Global energy networks: Insights from headquarter subsidiary data of transnational petroleum corporations

• A HQ subsidiary network is constructed to analyze global energy network.
• The quality characteristics of the HQ subsidiary network are examined.
• HQ subsidiary networks are different from trade networks.
• IOCs networks show disparate characteristics compared with NOCs networks.

Oil companies are powerful international actors, and have formed complex networks by building relationships from their headquarters (HQs) to subsidiaries. However, we do not know much about these networks as energy trade networks. In this paper, we select HQ subsidiary data of the most powerful oil companies in Fortune Global 500, and employ network analysis, Gini coefficient and Herfindahl index to investigate the network centrality, inequality and regional characteristics. We find that HQs are concentrated in the Unites States, Western Europe and East Asia while subsidiaries are more dispersed in both producing and consuming countries. Compared to the trade networks, HQ subsidiary network is more complex and displays greater inequality, especially in the out-degree network. IOCs (international oil companies) and NOCs (national oil companies) show different preferences for choosing subsidiaries locations and form different networks based on their industry value chains. A more complicated network including IOCs and NOCs will be more flexible in respond to market competition and geopolitical situation. HQ-subsidiary energy networks should be seriously considered along with the international diplomatic relations when making transnational energy policies and trading.