A number of Korean businesses went bankrupt, either because of dishonest practices or because the possible Korean share of world markets for some products, like automobiles, had been overestimated.
Overestimation and bad practices led to the demise of many businesses. 
mnli hypothesis: Overestimation and bad practices led to the demise of many businesses.  premise: A number of Korean businesses went bankrupt, either because of dishonest practices or because the possible Korean share of world markets for some products, like automobiles, had been overestimated.