Golub Capital BDC Inc is an externally managed, closed-end, non-diversified management investment company. Its investment objective is to generate current income and capital appreciation by investing in senior secured and one-stop loans in United States middle-market companies. It also invests in the second lien and subordinated loans, warrants, and minority equity securities in United States middle-market companies. The company generally invests in securities that have been rated below investment grade by independent rating agencies or that would be rated below investment grade if they were rated.