A mortgage lender is a best described as a "financial institution", ie a bank, or company, who will loan you a certain amount of money so as you may purchase the home that you, previous to metting the mortgage lender, could not afford. The deal is that you are loaned a sum of money to buy a mortgage that at the end of it you will have garnered enough money to pay back the mortgage lender. Mortgage lenders have access to large amounts of money which they usually attain through buying and selling stocks and bonds. By knowing when to buy and sell on the stock market, mortgage lenders can attain large amounts of funding for their business needs. They also gain money by raising interest on the money they lend out. Of course you should really make sure that before you enter into agreement with mortgage lenders that you really need the money you are borrowing.