In a true preapproval, the lender will present you with a letter, certificate or wallet-size card bearing your name and the maximum loan amount. It proves that an underwriter has completed all the checks and guaranteed your loan. Many lenders preapprove applicants, mostly because it lessens the chance that the buyers will look to other lenders once they find a house. Preapproval, however, does not preclude shoppers from changing prospective lenders at any time. The length of the preapproval process varies, depending on the lender and applicant.
Some banks can complete it in one day.
Lenders that promise 20-minute preapproval usually take that amount of time to gather and discuss the applicant's information, but the approval is still pending a review of the filer's resources, income and debt. Some lenders perform these checks over the phone.