Why might you want oligopolistic models of trade?

Why might you want oligopolstic models of trade?
“In 2004 Nokia’s share of Finnish GDP was 3.5 per cent and in 2003 it accounted for almost a quarter of Finland’s exports” (Neary, 2010).

“In 2004 Nokia’s share of Finnish GDP was 3.5 per cent and in 2003 it accounted for almost a quarter of Finland’s exports” (Neary, 2010).