Carlos Alves

Abstract
An exchange-traded fund (ETF) is a marketable security that tracks a stock index, a commodity, bonds, or a basket of assets. Therefore, returns of ETFs that track a benchmark index portfolio should mimic the returns of their benchmark indexes. If a benchmark index’s performance exhibits a seasonal pattern, then the performance of its associated ETF should replicate that pattern. This type of ETF performance seasonality is induced by trends in the market of securities in the benchmark index portfolio. Any other seasonality can be considered to be idiosyncratic. Based on a sample of 148 ETFs listed in NYSE Arca, this article provides evidence of a half-year effect (higher performance in the first half-year), a quarter effect (outperformance of the second quarter and underperformance of the fourth quarter), and month within the quarter effect (higher and lower performance in the first and third months of each quarter, respectively). Additionally, superior and inferior performance were observed in April and December, respectively. These seasonal patterns are not visible on benchmark indexes, with the exception of the unusually positive performance in April, which can be considered induced seasonality. The other effects, which cannot be attributed to underlying markets, are evidence of idiosyncratic seasonality. © 2019, © 2019 Informa UK Limited, trading as Taylor & Francis Group.

Abstract
There are two recognized tendencies in electricity markets: the development of spot markets and the increase of renewable electricity generation. These tendencies create dynamics in both price and volatility. In Portugal, there are powerful support schemes for renewable electricity. Therefore, the main sources for generating electricity in Portugal are renewable. This paper analyzes ex-post the impact of energy produced in special regime on the wholesale hourly spot market prices of Portuguese electricity during the period 2009-2016. It finds that special regime generation has a negative impact on the wholesale price. Effectively, an increase of special regime generation by 1.0 GWh, all else being equal, reduces the wholesale spot price by 3.9 (sic)/MWh. This represents 8.6% of the average wholesale price. Moreover, the substitution of 1.0 GWh of coal generation for special regime sources has an impact on electricity spot prices of, on average, -15.96 (sic)/MWh. This paper also concludes that using special regime generation to supply the future growth of demand will decrease wholesale electricity spot prices more intensively than using other technologies.

Abstract
Resumo Este estudo visa a identificar como mecanismos de controle externo e interno da governança corporativa, tipicamente considerados no setor empresarial privado, são aplicados ou transformados para o setor público nas empresas estatais. A partir de uma revisão do problema de agência e dos mecanismos propostos para sua mitigação no contexto empresarial, este estudo analisa a situação da governança das empresas estatais no Brasil e em Portugal, com vistas a comparar as soluções adotadas nos dois países e as necessidades de desenvolvimento. Além de compartilhar histórias e fundamentos culturais comuns, esses países são caracterizados como ambientes de pouca segurança aos investidores e fragilidade de instrumentos de solução de litígios, por estruturas de propriedade concentradas e por mercados de capitais ainda insuficientes para pressionar o comportamento das empresas, condições que fragilizam os mecanismos de mercado de controle externo e amplificam a influência das peculiaridades das questões internas de governança das estatais. As análises apontam significativas evoluções recentes nas práticas de governança das estatais, mas identificam desafios que ainda precisam ser direcionados.