Concerns about the loss of industrial competitiveness and leakage of CO2 emissions remain one of the major barriers to placing more robust CO2 mitigation obligations on industrial sectors in the EU. Existing literature has defined concepts, established the analytics, and offered some quantitative insights on the impacts of profitability, production and market-share. This study aims to take the analysis of competitiveness issues further by (a) more robust and comprehensive analysis of data, also with brief international comparisons, (b) a more systematic analytic framework, and © modelling and more extensive discussion on the two sectors of potentially greatest concern. We aim to shed some light on the determinants of the balance between short-run profit potential versus leakage over time, by examining in particular the relative magnitude of carbon-related costs for different sectors at the 4-digit SIC level, and discussing issues, evidence, and impacts on (and for two sectors, modelling) trade effects.