Fixed interest portfolios consist of investments that pay a set amount of interest over time. These investments are essentially loans, with one party lending money to another. In this type of transaction, the lender does not have a claim on the borrower's assets beyond the loan amount and interest. As long as the borrower fulfills their repayment obligations, they retain ownership of their assets and bear the associated risks and benefits. Key concepts in this area include interest rates, credit risk, yield curves, future contracts, and credit spreads.