Does divesting shares for ethical or religious reasons produce real change?

Making moral and religious investment decisions is right, but does not change the world. Shariah compliant screening of stock market investments enables investors to invest in accordance with their religious beliefs, but that is all it does. To combat the harm from alcohol, for example, requires other policies. Divestment campaigns do achieve one thing. That is to increase publicity about the issue concerned, whether that is climate change in the case of oil companies, or deaths from smoking in the case of tobacco companies. The ethical and religious reasons for divestment should not be ignored, since they matter to the individual shareholder. However ethical investors should not deceive themselves to believing that divestment will result in change in circumstances when it will not.