The concept of Corporate Social Responsibility (CSR) refers to the adoption of a model of business management in which the companies, being aware of their social commitment of co-responsibility in social and human development, hear, preserve and respect the interests of different parties and stakeholders, incorporating different needs of business planning and operating them through their decisions and activities. CSR is an important way for companies to develop their sense of commitment to society and environmental concerns. It is expected that companies should have self-regulating mechanisms through which their businesses can be monitored and ensure that the law is guaranteed as far as ethical standards and international norms. There are different research proposals for approaching CSR issues. A new relevant research direction distinguishes CSR from mere philanthropy and argues that CSR is one element of a firm’s strategic positioning. Our paper takes this direction and discusses the problem with a simple derivation of the Dorfman–Steiner publicity model. The Portuguese case is used to check the results of the model. Particular attention is given to banking firm motivations and strategies that put environmental sustainability in the first line of preoccupations.