It is not an economic philosophy, although its conclusion tends to support free market capitalism due to the lack of coercion inherent in such a system. Still, there is no dictum against collective ownership so long as it is voluntary. This is what anarcho-communism is all about.
Similarly, libertarianism has little to say about politics except for what follows directly from its central precept. Taxes are immoral because they involve coercion. Democracy is no better than dictatorship if it imposes the will of the many onto the few by force. And so on.