Seller Equity Importance?

[Tyler Scott]

Why exactly is it important for the seller to have a lot of equity? If someone has a $100K house that they still owe $90K on, why would it be less appealing to a wholesaler or flipper than someone who has 100% equity? I understand the mortgage is a lien on the property which must be paid before it can sell, but it' a little foggy why it is of importance. - T