The document discusses various types of debt securities including: 1) Short and long-term government securities such as treasury bills, notes, bonds, and savings bonds. 2) Short and long-term corporate securities like commercial paper, mortgage bonds, debenture bonds, and convertible debentures. 3) Long-term state and local bonds including general obligation bonds and limited obligation bonds. 4) Factors that determine bond quality ratings including earnings stability and legal protections.