You need to have 30% equity in your old home before you can buy a new home and also keep the old home.
Fannie Mae recently decided to change that requirement. Now as long as we can show market rent, even if you are upside down in equity on the current home, you can move to a new home with minimum down as long as you qualify for either both payments or the payments on the old home after rental credit.
YEAH!! Since so many people were upside down on their home, before September 2015 Fannie Mae was trying to avoid the bailing on properties while giving a new loan so they required that equity. Because the values overall have gone up and there are fewer foreclosures bringing down values, they decided it was safe to lift this requirement that was keeping so many potential move-up buyers trapped in their old home.