In this article, we examine whether comovement in the stock prices of pairs of Chinese firms connected to the same political network are systematically shaped by the prevailing coordination versus competition incentives of that network’s politicians. We find strong evidence from 2000 to 2012 (Jiang’s and Hu’s regimes) that stock price comovement is affected by the embeddedness of the firm–politician ties within the network. Among pairs of firms connected to a network through a common politician, we document an increase in stock price comovement. For those pairs of firms connected to a common network via separate politicians (rather than a common politician), we document a relative decrease in stock price comovement. This negative effect suggests that politicians’ relationships within these political networks are generally adversarial rather than cooperative in nature. These results become significantly weaker during Xi’s regime from 2013 to 2017, suggesting that Xi’s anti-corruption campaign and state-owned enterprise reforms may have attenuated these political network effects on the firms. Our additional tests also show that stock price comovement becomes even more positive (negative) in settings which are expected to increase the coordination or decrease the competition (decrease the coordination or increase the competition) of the politicians.