Does vertical integration reduce the cost of equity?

Faced with the increasing risk of supply chain disruption, more firms are using mergers and acquisitions or investments to expand their core business's upstream and downstream supply chain and improve their vertical integration. In this vertical integration trend, the cost of capital for core firms is crucial to coordinating the entire supply chain. We manually collected input-output matrix data of segmented departments and supply chain value-added data to explore how vertical integration impacts the cost of equity. Using A-share listed firms from 2008 to 2021 as our sample, the results of our regression analyses show that vertical integration plays a significant role in reducing the cost of equity. These results remain consistent throughout a series of robustness tests. The channel tests indicate that vertical integration can reduce the cost of equity by reducing operating risk and mitigating information asymmetry. Additional analyses show that vertical integration's impact on the cost of equity is more pronounced for firms with more intense industry competition, lower product market positions, lower supply chain concentration, weaker corporate governance, and more aggressive strategies, as well as firms in regions with lower marketization processes and weaker trust environment. Our findings contribute to the literature on the economic consequences of vertical integration from the perspective of corporate financing behavior and extend the literature on cost of equity determinants to the field of supply chains.