The difficulty of applying exclusion criteria in ethical portfolios

A main problem for socially responsible investors is deciding which companies should be included in their investment portfolio. Small investors may decide not to invest in companies they know are not behaving responsibly. Therefore, discredited companies will not be included in their portfolios, as they will understand those companies cannot be defined as ethical. To implement this procedure properly and apply it to big portfolios is a complex exercise which requires big amounts of information and the problems faced by investors applying such exclusion criteria to select their portfolio.