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The optimization of investment portfolios is a topic of major importance in financial decision making, with many relevant models available in the relevant literature. The purpose of this paper is to perform a thorough comparative assessment of different bi-objective models as well as multi-objective one, in terms of the performance and robustness of the whole set of Pareto optimal portfolios.

In this study, three bi-objective models are considered (mean-variance (MV), mean absolute deviation, conditional value-at-risk (CVaR)), as well as a multi-objective model. An extensive comparison is performed using data from the Standard and Poor’s 500 index, over the period 2005–2016, through a rolling-window testing scheme. The results are analyzed using novel performance indicators representing the deviations between historical (estimated) efficient frontiers, actual out-of-sample efficient frontiers and realized out-of-sample portfolio results.

The obtained results indicate that the well-known MV model provides quite robust results compared to other bi-objective optimization models. On the other hand, the CVaR model appears to be the least robust model. The multi-objective approach offers results which are well balanced and quite competitive against simpler bi-objective models, in terms of out-of-sample performance.

This is the first comparative study of portfolio optimization models that examines the performance of the whole set of efficient portfolios, proposing analytical ways to assess their stability and robustness over time. Moreover, an extensive out-of-sample testing of a multi-objective portfolio optimization model is performed, through a rolling-window scheme, in contrast static results in prior works. The insights derived from the obtained results could be used to design improved and more robust portfolio optimization models, focusing on a multi-objective setting.

Considering environmental, social and governance (ESG) factors is vital in climate change mitigation. Energy companies must incorporate ESG into their business plans, although it unquestionably affects their corporate financial performance (CFP). This paper aims to investigate the effect of ESG on energy companies’ profitability through return on assets by analysing the combined score and individual dimensions of ESG.

The study examined a panel data sample of 911 firm-year observations for 85 European energy-sector companies during 1995–2020. Two distinct modelling specifications were applied to explore the impact of ESG components on the CFP of EU energy companies. The financial data and ESG scores were obtained from the Thomson Reuters Eikon database in July 2021.

The empirical findings revealed that energy companies’ profitability is marginally and negatively affected by their ESG performance. Whereas independent evaluation of the ESG subcomponents indicated that environmental responsibility has a significant negative effect. In contrast, corporate social and governance responsibilities are positively but not significantly associated with the company’s CFP.

This study fills a research gap in the ESG–CFP literature in the European energy sector, a pioneer in sustainable development. To the best of the authors’ knowledge, this study’s originality lies in its analysis of ESG factors’ role in profitability by considering different EU countries and energy sectors.

This paper aims to examine whether credit ratings of banks are related to their location, i.e. inside or outside the Euro Area.

The authors estimate a multilevel ordered probit model for banks’ credit ratings in 2011 and control for bank-specific factors. They use the overall ratings and the external support ratings provided by Fitch as the dependent variable.

Banks located in Euro Area member countries, on average, receive a higher credit rating from Fitch than banks located outside the Euro Area. Evidence for a “too-big-to-fail” and a “too-big-to-rescue” effect was also found.

The monetary union effect on banks’ credit ratings may be affected by the period under investigation. The ratings refer to August 2011, when the European sovereign debt crisis was at its height. This implies that, if anything, the Economic and Monetary Union (EMU) effect is underestimated.

Large banks in the Euro Area receive higher credit ratings, so they have a competitive advantage over small banks located outside the Euro Area.

The present evidence suggests that small European countries with an extensive banking sector will be better off if they are member of the European EMU.

The relationship between location of banks and their credit ratings has hardly been researched before. The present evidence is directly related to a debate in the literature on this issue.