"Business combination" means enterprise integration through the stockholding, merger, etc. of two or more companies.

As you can see in the above illustration, if Companies A and B, which had shared the market, were merged, the new Company AB would monopolize the market, eliminating competition.
The product of Company AB would be only available in the market, so consumers would have no choice but to buy the product. This situation reduces consumers' benefits. For this reason, such anti-competitive mergers are prohibited. Business combinations, including stock acquisitions, company splits, joint stock transfers and the acquisition of business are regulated in the same manner as mergers.
A business combination that does not interfere with competition between companies in the markets is not considered a problem. Companies intending certain business combination, both domestic and overseas, are required to notify the Fair Trade Commission for preliminary investigations on whether or not the intended business combination is anti-competitive.