Financial holding companies, in order to boost their international competitive advantages, are planning to diversify their operations to serve different product lines and different customer markets by integrating the banking sector, insurance sector, and securities sector so that customers can enjoy the convenience brought about by a one-stop financial instruments shopping experience. The insurance sector is known for its numerous clients and funds and fulfillment of the pre-requisite of internal and external growth (through mergers and acquisitions), and hence has become a target proactively pursued by financial holding companies whose current domain does not include insurance. Therefore, through this study, I will analyze the impact from merging insurance companies to financial holding company: whether it can maximize the performance; and observe the complementary effect from financial holding company banking and insurance dual engine operation: whether it can get multiplier capability. The study data is the quarterly data over the 10 years from 2009 to 2018 and an empirical model is created with quantitative methods such as the panel data regression model regarding the variables being explored. Empirical results show that the fierce competition among financial holding companies or in the financial sector has resulted in varied impacts of the presence or non-presence of insurance under a financial holding company on its respective management performance indicators or competitive advantages despite the different entities involved and the superiority or inferiority in performance. Therefore although merging insurance companies is not an important factor of financial holding company performance, however within enormous funding and customer base, financial holding company contains insurance sectors have indeed contributed to a relatively powerful finanacial outlook, scale of operation (assets), and share price.The gradual widening of the gap from the competition shows that there should be comparable impacts.