Hello,

While all are extremely important, I have found that the most important thing for a product manager to know would be to stay informed about the industry and market data. The reason why I say this is because it should also include knowing about competitor products as well as the aspects that affect product sales. In a way, it makes it hard to pinpoint one aspect from the ones that you have listed. Also, I think that something else that is important for product managers to know would be innovation and new discoveries (either from smaller start-up companies or academic research) that would be applicable for the product that they are responsible for managing.