We provide novel causal evidence on the impact of horizontal relationships between financial intermediaries. We study how the exogenous loss of established ties between venture capital firms (VCs) and investment bank underwriters, due to underwriter mergers and closures, affects VCs' ability to take portfolio companies public. Using a difference-in-differences approach, we find such disruptions decrease VC IPO exits by 9.5% and reduce fund multiples by 7.8%. Our findings highlight the economic significance of relationship-specific capital, particularly human capital, in facilitating access to capital markets, providing new insights into how intermediary networks shape VC performance and firms' paths to public markets.