When a lender (or any corporation with loans) or a company with income-producing assets puts aside a group of these assets for sale to an investment bank or other financial institution, asset securitization is born. This institution frequently combines these assets with similar ones from other sellers before forming a special-purpose vehicle (SPV)—an organization created especially to buy, package, and issue the assets as a single security. The issuer then sells the securities to investors, most of whom are institutional (hedge funds, mutual funds, pension plans, etc.). The investors are paid at a fixed or adjustable rate from a trustee account that is funded by the cash flows generated by the asset portfolio. The initial asset portfolio is sometimes divided into tranches by the issuer. Each tranche is sold individually and has a distinct level of risk, as evidenced by the credit rating assigned to it.