We survey institutional investors on capital structure decisions of the firms they invest in. We document their capital structure preferences, as well as determinants affecting the strength of their impact on firms. Over 82% of investors believe that they strongly influence security issuance choices, especially for smaller, younger and more constrained firms. Unlike CFOs, investors consider agency costs of free cash flow important in their decisions. We also find support for the pecking order and market timing theories. Most investors consider financial constraints when investing, with components of the Kaplan-Zingales and Whited-Wu indices dominating age and size as proxies. Joint with Stephen Brown, Marie Dutordoir, and Yulia Veld-Merkoulova.