The purpose of this study is to investigates how the contestability or the probability of forming a controlling coalition among multiple blockholders affect firm performance. We also examine the interactions role of the second blockholders who are a foreign/institutional investor and stock liquidity in effects of blockholders contestability or the probability of forming a controlling coalition among multiple blockholders on firm performance. The analysis period is from 2005 to 2017, and it is analyzed through panel regression analysis based on the panel data for Korean listed companies. The results provide three evidence. First, this study shows that blockholders contestability have a positive effect on firm performance, while the probability of forming a controlling coalition among multiple blockholders have a partially negative impact on firm performance. Second, there is no evidence that second blockholder presence interacts with between the contestability or the probability of forming a controlling coalition of multiple blockholders influence and company performance. Third, we find that the effects of blockholders contestability or the probability of forming a controlling coalition on firm performance decrease with higher stock liquidity. The results of this study have contributed to the understanding of the relation between the contestability or the probability of forming a controlling coalition among multiple blockholders and firm performance in view of shareholder activism or exit mechanism, which is a recent issue in the Korean stock market.