dianna al lia olick explains. >> reporter: in phoenix, arizona one of the hardest hit markets of the crash, home prices are up over 40% from the bottom of 2011. that cut in half the number of borrowers that owe more on the mortgages than their homes are worth. nationwide, millions are drowning in negative equity and some are asking could it all happen again? one company is saying yes and offering consumers insurance for that possibility. >> under water mortgage protection is the first of its kind insurance product that we've created for homeowners who might want or need to move at a time when they are in a negative equity position. >> reporter: basically, it's gap insurance from kansas based amtrust financial. it covers the under water amount, should you need to sale your home. consumers were divided. >> it's worth considering if you leverage risk. >> i think it's not a good use of money. >> reporter: to qualify, you must have at least 10% equity in your home now and you cannot refinance during the coverage period. the average monthly premium is between 40 and $50 and not for high-en