The article analyzes different sectorial portfolios of stocks to understand the relationship between risk and return. By using the Modern Portfolio Theory, the researchers found that as the risk increases, the expected return also increases, but at a decreasing rate. Different sectors show varying behaviors in terms of risk-return relationships, with some sectors consistently outperforming others. The study suggests that there may be information asymmetry or investor bias towards certain sectors, leading to differences in expected returns for the same level of risk.