According to Anglo-American property law, a mortgage occurs when an owner (usually of a fee simple interest in realty) pledges his or her interest (right to the property) as security or collateral for a loan. Therefore, a mortgage is an encumbrance (limitation) on the right to the property just as an easement would be, but because most mortgages occur as a condition for new loan money, the word mortgage has become the generic term for a loan secured by such real property. As with other types of loans, mortgages have an interest rate and are scheduled to amortize over a set period of time, typically 30 years. All types of real property can be, and usually are, secured with a mortgage and bear an interest rate that is supposed to reflect the lender’s risk.
Many other specific characteristics are common to many markets, but the above are the essential features. Governments usually regulate many aspects of mortgage lending, either directly (through legal requirements, for example) or indirectly (through regulation of the participants or the financial markets, such as the banking industry), and often through state intervention (direct lending by the government, direct lending by state-owned banks, or sponsorship of various entities). Other aspects that define a specific mortgage market may be regional, historical, or driven by specific characteristics of the legal or financial system.
Mortgage loans are generally structured as long-term loans, the periodic payments for which are similar to an annuity and calculated according to the time value of money formulae. The most basic arrangement would require a fixed monthly payment over a period of ten to thirty years, depending on local conditions. Over this period the principal component of the loan (the original loan) would be slowly paid down through amortization. In practice, many variants are possible and common worldwide and within each country.
Lenders provide funds against property to earn interest income, and generally borrow these funds themselves (for example, by taking deposits or issuing bonds). The price at which the lenders borrow money therefore affects the cost of borrowing. Lenders may also, in many countries, sell the mortgage loan to other parties who are interested in receiving the stream of cash payments from the borrower, often in the form of a security (by means of a securitization).