Credit ratings are evaluations of a borrower's ability to repay debt. They are issued by credit rating agencies and help lenders assess risk. The document discusses the history and purpose of credit ratings, how agencies like Moody's, S&P, and Fitch assign ratings, and the role ratings play in capital markets by providing benchmarks for investors and reducing uncertainty. It also outlines the rating process, methodology, and categories from investment grade to speculative/junk status.