What is a tri-merge credit report and why is it used in mortgage lending?

A tri-merge report, also called a residential mortgage credit report, pulls your full credit file from all three bureaus into one consolidated document for the lender to review. Mortgage underwriters use the middle of your three FICO scores — not the average — as the qualifying score. If multiple borrowers are on the loan, lenders typically use the lower middle score between applicants. This process ensures lenders catch any negative items that might appear on only one bureau's file.