If we were to compare peers in the same industry across the globe, we would see a range of ratios (i.e. P/E etc). This does not necessarily mean that the a firm with a lower ratio in one country is of better value compared to a firm with a higher ratio in another country. 

One reason could be that most investors, especially retail investors, have a greater preference for investing in markets closer to where they are situated. For example, a middle class salaried man working in Singapore will more likely place his money in the Singapore exchange rather than say the NYSE. 

This is not surprising given the availability bias where the stocks have greater coverage with information easily coming across on a regular basis through the news, papers, or online articles.  Thus, with all the information on hand, the salaried ...