# The Mortgage Underwriter: companion files

Julian R. Sterling

## What is here

- **Mortgage_Underwriter_Model.xlsx**: the workbook that rebuilds the Calloway file and reproduces the figures of the book with live formulas. Sheets: Read Me, Inputs, Income, Payment and DTI, Assets, Collateral, Contrast Files, QC and Repurchase, Checks.
- **Mortgage_Underwriter_Toolkit.docx**: the checklists of Appendix B (first read, income documentation, self-employed income worksheet, assets, credit report, appraisal review, condition writing, pre-closing, fraud red flags, file notes), in editable form.

## Which sheet answers which chapter

- Chapters 4 and 5: Income (base salary, bonus average, self-employed income by year, lower year against two-year average)
- Chapters 6 and 10: Payment and DTI (principal and interest, mortgage insurance, housing ratio and DTI at application, after the price change and after the new debt)
- Chapter 7: Assets (funds to close, reserves, the large deposit test)
- Chapter 9: Collateral (the appraisal shortfall and the new loan amount)
- Chapters 11 and 12: Contrast Files (FHA, VA, jumbo, bank statement, DSCR)
- Chapter 14: QC and Repurchase

## Two inputs to change first

1. On Inputs, set the 2025 Schedule C net profit back to the 2024 level: see how much the self-employed income and the DTI move.
2. On Inputs, set the appraised value equal to the original contract price and the amended price to the same figure: see the loan amount and the payment the borrowers would have had. Reset the inputs afterwards: the Checks sheet compares the workbook with the figures printed in the book.

Blue type on a light blue background is an input, black type a formula. No macro, no circular reference, no external link. The Checks sheet should read ALL CHECKS OK on the default inputs. The workbook does not run an automated underwriting system, does not price loans and does not compute VA residual income.

Brightwater Home Lending, the Calloways and every other name in the case are fictional; the model is simplified; all case figures (note rates, mortgage insurance rate, investor terms) are illustrative assumptions, not market terms or forecasts. Provided as is, without warranty. Not lending, legal, tax or accounting advice.