This paper investigates the relationship between political connections and firm value, as well as the moderating effect of internal control under exogenous shocks. By manually collecting 20 staggered downfall events during China's anti-corruption campaign since 2012, we observe that the termination of political connections results in an approximately 2% decline in equity value for private firms at the point of event, and effective internal control attenuates the negative price reaction to the loss of linkage. These findings infer the existence of benefits from maintaining political ties in business operations. Despite the value decline for connected firms, we further conclude that internal control system can be a useful channel of value protection in political shocks. Finally, our results survive a battery of sensitivity tests. •The termination of political connections during anti-corruption campaign leads to a decline in equity value for private firms•Internal control is an effective mechanism to mitigate the loss of economic value in negative events•The exogenous shock provides a quasi-natural experiment to examine the causal effect of political connections on firm value