A number of specific large conglomerates hold competitively dominant positions based on user data and increasingly exploit them to expand their business areas. In this context, voices have been raised to call for active regulation by competition authorities against the attempts to secure monopoly status by exploiting data. With respect to business combination deliberation, since the 2007 Google/DoubleClick business combination incident, competition authorities across the world including the EU have discussed various competition law issues on business combination deliberation involving IT companies and big data. To date Korea, however, has had no deliberation case on business combination of IT company involving big data, requiring relevant deliberation criteria for business combination. The study aims to examine the existing cases in the EU, at European level and in some of its member states including Belgium.