equity investment

I'm not sure if I have understood the question? I value a company based on what it might earn in the future and how likely it is to make those earnings, from this I get a maximum price I would pay and I then see if the market price is above or below my estimate of fair value. If the business is cheaper than what I think it is worth and if there is nothing else which is even cheaper then I buy it. This is the same for both domestic and international markets but you have to remember differen't countrys have different accounting standards, different tax systems, different demographics in terms of the likely customer base...

Equity is very useful to measure the economy strength within a country or a regions. It's the representation of the corporates or government linked company financial strength. Therefore, we can have an idea the economy stage a country or a region is in. From there, we can make our decision base on this piece of information.