trade

if the companies of two countries 

compete for the market in a third country 

then that could entice one of the the two countries 

to subsidize it's own companies 

so that it's own companies get an unfair advantage 

against the other country's companies 

when exporting to the third country 

or when those two countries export to each other 

but if one of those two countries 

instead tries to increase the size of the market 

instead of subsidizing it's own companies 

then that would benefit that country 

but it would also decrease competition 

between the companies of the two countries 

which would benefit both countries 

example: 

if china subsidizes it's own companies 

against american companies 

when china is exporting to usa and eu 

then usa could answer 

by implementing tariffs against chinese companies 

and usa could influence eu 

to implement tariffs against chinese companies 

but if china instead tries to increase the size of the market 

by exporting more to africa, latin america, asia and russia 

then that would decrease competition 

between chinese and american companies 

and could increase the demand for products and services 

from both chinese and american companies 

if a country subsidizes it's own companies 

then that could give those companies an advantage 

against the companies of other countries 

and the buyer could benefit from that 

but the country that subsidizes it's own companies 

looses money by essentially giving that money to the buyer 

example: 

if china subsidizes chinese companies 

and those companies exports to eu 

then eu gets a cheaper price 

while china pays for that 

so china would be essentially giving eu money 

to buy from chinese companies