In the higher level course, it is important to understand that barriers to entry are an important source of monopoly power and that they can occur for a number of reasons. Some ways they can occur are through anti-competitve behaviour (mis-using your market dominance), cartels and collusion, and through patents. In the news they are constantly reporting on issues relating to these, and they are often associated with technology firms. Apple, Google, Intel and Microsoft are a few of the household names that are often accused of anti-competitive behaviour. Below are a number of links to articles on this issue from the past year.