What is PMI?

Basics of private mortgage insurance (PMI) If your down payment on a home is less than 20 percent of the appraised value or sale price, you must obtain private mortgage insurance, known as PMI, with your lender. This will enable you to obtain a mortgage with a lower down payment because your lender is now protected against any default on the loan.

PMI charges vary depending on the size of the down payment and the loan, but they typically amount to about one-half of 1 percent of the loan, according to the Mortgage Bankers Association of America. Mortgage insurance premiums are not tax deductible.

Example Let's say you put down 10 percent or $10,000 on a $100,000 house. The lender multiplies the 90 percent loan, or $90,000, by .005. The result is an annual PMI of $450, which is divided into monthly payments of $37.50.

Most home buyers need PMI because 20 percent of the sale price on a home is a lot of money; for instance, that's $20,000 on a $100,000 home. Home buyers must maintain the PMI premiums until they cross that one-fifth-of-principal threshold, a process that can take years in longer-term mortgages.

Tip Keep track of your payments on the principal of the mortgage. When you reach the point where the loan-to-value ratio hits 80 percent, notify the lender that it is time to discontinue the PMI premiums. The Homeowners Protection Act of 1998, which took effect in 1999, requires lenders to tell the buyer at closing how many years and months it will take for them to reach that 80 percent level and cancel PMI. Lenders must automatically cancel PMI when the balance hits 78 percent.