Mortgage Lenders Pull Three Files And Use The Middle

Most credit decisions rely on a single bureau. Mortgage lending conventionally uses all three, and the way it combines them changes which errors matter.

The tri-merge report

A tri-merge combines reports from the three national bureaus into one document, showing each account as reported by each bureau side by side.

Differences appear immediately. An account may show a different balance, a different status, or exist on two files and not the third.

Those differences are ordinary. Bureaus receive data from different furnishers on different cycles, and none of them holds a complete record.

Why the middle score is used

Each bureau produces its own score from its own data. Using the lowest would be excessively conservative and using the highest excessively generous.

Taking the middle discards one outlier in each direction, which reduces the influence of a single bureau holding incomplete or erroneous data.

The consequence is that improving the highest score changes nothing. Only movement that shifts which score sits in the middle affects the decision.

How joint applications are handled

Each applicant is scored separately, producing a middle score for each. The lender then applies a rule to combine them.

A common convention uses the lower of the two applicants' middle scores, on the reasoning that the weaker file represents the risk.

That rule can make adding a co-borrower with strong income but a weaker file counterproductive on pricing, even where it helps on qualifying income.

The score versions differ from consumer scores

Mortgage underwriting has long used particular score versions, which are not the newest models and are not the ones consumer-facing services usually display.

A number seen on a monitoring app can therefore differ noticeably from the one the lender pulls, without either being wrong.

The scoring models accepted for mortgage lending are set by the entities that buy the loans, and requirements in this area have been under revision.

What this means for correcting a file

An error on the bureau holding the middle score is the one that matters. The same error on the bureau holding the highest score has no effect on pricing.

Which bureau sits in the middle is not fixed, so an error worth correcting on one application may be irrelevant on another.

Some lenders offer a rapid rescoring process where corrected information is supplied with documentation, but it requires the underlying correction to exist first rather than substituting for a dispute.