Top level execs are not known for their grasp of leading-edge management theory or interest in the debate of academic nuances. They are known for bold extrapolation/wild BS'ing on the basis of a few half-remembered factoids.In this respect, a distance-learning post-grad diploma in management studies will provide all the theory you need, without the high course and opportunity costs of a full-time Masters. You can top it up by reading accessible business press, such as the Harvard Business Review, and anything by Martin Lukes.