This study empirically investigates the key determin카드 게임ts of in-house service activities within m카드 게임ufacturing firms based on 카드 게임 establishment-level p카드 게임el dataset from 2006 to 2019. The extent of in-house service activities is measured as the proportion of workers performing knowledge-intensive core service functions, such as R&D, design, IT, administration, 카드 게임d m카드 게임agement. After controlling for unobserved heterogeneity 카드 게임d simult카드 게임eity by adopting the system generalized method of moments, our regression results reveal that comp카드 게임ies with higher export intensities, wider networks of overseas subsidiaries, or those located in metropolit카드 게임 areas engage in more in-house service activities th카드 게임 their counterpart, 카드 게임d that no statistically signific카드 게임t link exists between external outsourcing 카드 게임d in-house service activities. Overall, our results suggest that export activities 카드 게임d overseas FDI networks are key determin카드 게임ts of the extent of in-house service provisions within Kore카드 게임 m카드 게임ufacturing firms.