Homeowners may be selling themselves short when it comes to the amount of equity in their homes and faulty valuation tools may be the culprit, says a new Fannie Mae analysis released last week.As many as 15 million homeowners are underestimating how much equity they’re actually sitting on, especially as house prices continued to rise over the past several years. CoreLogic estimates of the percent of homeowners having significant home equity was much higher than the percent who actually perceived themselves as having equity in Fannie consumer surveys. Many homeowners also mistakenly think a large downpayment is required to buy a home, according to data from Fannie’s National Housing Survey. This means the number of consumers...