PMI plays an important role in the mortgage industry by protecting a lender against loss if a borrower defaults on a loan and by enabling borrowers with less cash to have greater access to homeownership. PMI makes it possible for the borrowers to buy a residential home with as little as 5 percent to 10 percent down payment. You can buy a home now without waiting years to save for a larger down payment. PMI also applies to homeowners who are interested in refinancing their existing loan with a loan amount over 80% of the current property value. The premium is an additional amount to be paid every month with the regular mortgage payment of principal, interest, taxes and insurance. Click here for more in-depth information.