What are private mortgages? Why do we as mortgage brokers provide you an option to pick Private Mortgage Investing? Private Mortgage Investing or Private Money Lending refers to a private individual providing a loan to another with real estate as collateral. Private mortgages are generally short termed and are interest only loans that can range in length, anywhere between 1 year to 3 years. These kinds of ‘interest only loans’ do not usually require homeowners to pay any principal on their mortgage down, but instead require interest payments each month.