Those are only public companies. They aren't accounting for a lot. This study hardly reaches a definite conclusion and certainly not one as ridiculous as the thought of these companies being at the top of the pyramid.
Only as ridiculous as the notion that if some evil individuals could successfully collaborate and conspire to control the world, they absolutely would do it.
Come on, is this really so hard to believe? Individuals attempting to conquer and rule the world is the most common theme throughout history. Its much easier to do today, and not a single shot has to be fired.