This study investigates whether kinship-driven social ties, proxied by shared surnames among top executives, influence short-term performance in merger and acquisition (M&A) transactions in China. Using a comprehensive sample of Chinese listed-firm M&A events from 2000 to 2023, we employ an event-study methodology with cumulative abnormal re- turns (CAR) over multiple windows ([-1, +1], [-2, +2], and [-3, +3]) to gauge market reactions. Our OLS panel regression models with fixed effects reveal that the presence of executives with the same surname in the acquiring and target firms is associated with sig- nificantly higher announcement-period CARs. This effect is especially pronounced for rarer surnames, suggesting that a smaller clan-group identity fosters stronger in-group trust and cooperation, consistent with social identity and in-group favoritism theories. We further find that surname overlaps between acquirer and target increase the likelihood of deal suc- cess, indicating that kinship-like ties can facilitate negotiation and agreement. Notably, the positive impact of shared executive surnames on CARs is more pronounced in state-owned enterprises (SOEs) than in non-SOEs, implying that in more formal or resource-constrained institutional environments, informal relationship capital plays a crucial role. By introducing surname similarity as a novel measure of inter-firm social connection, this research offers new theoretical insight into how deeply embedded cultural bonds (family names and clan heritage) can shape corporate outcomes. The findings contribute to the growing culture and finance literature by opening a fresh perspective on guanxi-like trust in M&A, and they carry practical implications for M&A strategy and corporate governance in China.