Short description of Mortgage Prelude 2.6.1.011: This easy-to-use program will save you countless time and hassle by determining how much of a loan you are qualified for BEFORE you ever have to fill out a loan application. It uses the guidelines set forth by the Federal National Mortgage Association (a.k.a. Fannie Mae) to determine the loan amount you are qualified for. In fact, the Fannie Mae Guidelines are likely the same ones your lending company is using.