This features in company law. It is similar in form to an extraordinary resolution but, in addition, twenty-one days’ notice of the meeting at which it is to be proposed is necessary. Special resolutions are normally reserved for important changes in the constitution of a company, e.g. alteration (where permissible) of the memorandum of association, changes in the company’s articles of association, reduction of capital, etc.
As with an extraordinary resolution the majority needed is three-quarters of those voting, whether present or not. This means that a resolution, where no poll is asked for, could effectively be passed by a small number of members present at the meeting, despite the fact that the motion would have been rejected had all those entitled to vote done so either personally or by proxy.
Reference: The Penguin Business Dictionary , 3rd edt.