Corporate Bonds
Debt issued by corporations: secured bonds (mortgage bonds, equipment trust certificates) are backed by specific collateral; debentures are backed only by the issuer's credit; subordinated debentures rank below other debt.
Corporate interest is fully taxable at every level, so corporates must out-yield munis and Treasuries of similar maturity. Income bonds (adjustment bonds) pay interest only if earned and trade flat — without accrued interest — a detail the exam likes.