Should the world markets be combined to be a single market?

In most of our time currently, the markets across the world have very similar response to the same information. For example, after the surprising outcome of the Brexit referendum, the markets around the world fell sharply. Such phenomenon is understandable, as in the globalized world, the markets around the world intersect with each other. If the markets are so interacting with each other around the world, maybe we could ask if the increasing interdependence is enough to combine these markets together to form a single global market.

I think such change could improve efficiency, but damage the nations' interests and reduce the employment rates in some countries. Having a single market means it is not necessary to set up another office in a different country to do a similar job about making activities in the market. The people who work in a certain field will be put together and doing their work together, which could improve the efficiency, compared with if they work separately across the world. When the efficiency and productivity is improved, there is no need to maintain the same amount of employees, so there will be a job cut in the industry. Moreover, we have to admit some countries are more capable to provide professional workers than other countries, so the countries which have more professional workers will take the jobs from the countries which have fewer professional workers. Although it always happens, when there is a single market, it could be more significant. In addition, if the industries in one country are not very active in the financial markets, when there is a single global market, the resources put into this country by the financial industries could drop sharply.

Therefore, if we are going to have a single global market, it makes sense to the globalized financial industry and could improve the efficiency and productivity in the industry; however, it could significantly increase the level of competition in the industry and the competition between the nations and could probably widen the wealth gaps within individuals as well as nations.