As the oil and gas industry pushes into ever more sensitive areas, the risks are increasingly being handled by complex chains of contractors. Effective management of contracting chains — from early assessments to communication and oversight — is critical to ensure good social and environmental performance. This responsibility should be shared throughout the contracting chain, across company departments, and between government and industry, with space for independent third-party oversight. From the deep waters of the Russian Arctic to the tar sands in the Congo Basin, new technological challenges and natural hazards are fast becoming the norm in the oil and gas industry. High prices and concerns about energy security have driven expansion of the industry into regions that carry heightened technological, political and social risks. Less well known are the challenges the industry faces as a result of its complex contracting chains. While most people are familiar with a handful of brands such as BP, Shell and ExxonMobil, at least 70 per cent of a typical oil or gas project is contracted out to lower-profile service providers and their subcontractors. The fallout from the April 2010 Gulf of Mexico disaster has shone a spotlight on alleged systemic failures and ongoing difficulties in these contracting relationships — and on their importance for good environmental and social performance. Shared value, shared responsibility draws on three years of research and interviews within the sector to highlight an array of critical challenges facing oil and gas companies involved in complex supply chains, and to identify urgent and longer-term actions for progress