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 securityor 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.
Mortgage lending is the primary mechanism used in many countries to finance private ownership of residential and commercial property (see commercial mortgages). Although the terminology and precise forms will differ from country to country, the basic components tend to be similar:
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).
Mortgage lending will also take into account the (perceived) riskiness of the mortgage loan, that is, the likelihood that the funds will be repaid (usually considered a function of the creditworthiness of the borrower); that if they are not repaid, the lender will be able to foreclose and recoup some or all of its original capital; and the financial, interest rate risk and time delays that may be involved in certain circumstances.