I examine the corporate financing implications of the emergence of non-bank institutional investors, primarily collateralized loan obligations, in the market for corporate loans. The evidence suggests that institutional loans are primarily a substitute for corporate bonds. When the supply of institutional loans increased in the years before 2008, relatively risky firms decreased their use of bonds, a pattern that was reversed in the years after 2008. There is no evidence that institutional loans are a substitute for other types of financing, including revolving credit, and only modest evidence that institutional loans are a substitute for bank funded term loans. The results suggest that non-bank lenders are willing to provide senior-secured financing and that firms view term loans and bonds as close substitutes. These results have implications for our understanding of firm capital structures choices and the structure of financial intermediaries.