An underwriter’s job is to decide whether the loan will be repaid, using nothing but the file in front of them. The “tricks” are simply the five things the underwriter checks, and what you can do about each before you apply.
1. Credit: the score, and what is behind it
Payment history and amounts owed are the two biggest components of a FICO score, at 35% and 30% of the total. So the two most useful moves before applying are simple: pay everything on time for as long as possible beforehand, and get revolving balances below 30% of their limits — lower is better.
What score you need depends on the loan. Fannie Mae’s automated underwriting system no longer enforces a fixed minimum score. Loans underwritten manually still need a 620 for a fixed-rate loan (640 for an ARM), and most lenders keep floors of their own. FHA allows a 580 score with 3.5% down, or 500 to 579 with 10% down, subject to lender overlays. Lenders pull a tri-merge report from all three bureaus and, since April 22, 2026, may use VantageScore 4.0 or FICO Score 10T alongside the classic FICO versions; both newer models can count rent, utility and phone payments when reported.
Pull your own reports first. They are free weekly from all three bureaus at AnnualCreditReport.com, and fix any errors before the lender pulls. While the loan is in process, do not open new accounts and do not close old ones: the underwriter must confirm you have taken on no new debt since the report was pulled, and any new payment gets added to your ratios. Rate-shopping between mortgage lenders is fine — FICO groups mortgage inquiries inside a 14-to-45-day window depending on the version — but finish inside two weeks to be safe. See how to raise your credit score for the mechanics.
2. Income: two years, and a reason to believe it continues
Underwriters evaluate your most recent two years of employment and want a two-year history for each income source. Income received for a shorter period, but at least twelve months, can be considered when the lender can justify it. Gaps within the most recent twelve months must be analyzed, and if you hold more than one job, the file should show no gap longer than a month unless the work is seasonal. Income with a known end date — a contract, a benefit, alimony — must be expected to continue for at least three years from closing to count.
Bonus, overtime, commission, self-employment, rental and investment income all count, but each has its own documentation and averaging rules; if any of your qualifying income is variable, ask your loan officer what they need before you apply. Expect a verbal verification of employment in the ten business days before closing and, if you are self-employed, verification that your business exists within the 120 days before closing.
3. Debt-to-income: the ratios that actually apply
Your front-end ratio is the full housing payment — principal, interest, taxes, insurance, plus association dues — divided by gross monthly income. Your back-end ratio adds every other monthly debt on the credit report. The old 28/36 rule of thumb is a budgeting guideline, not a lender limit. In 2026, Fannie Mae’s automated system caps conventional back-end DTI at 50%; FHA’s standard guideline is 31% front-end and 43% back-end, with automated approvals possible up to roughly 46.9% and 56.9% for borrowers with compensating factors. Lenders routinely approve above 28/36; whether you should borrow that much is the question How Much House Can You Handle in 2026? takes up. If your ratios are over the line, the levers are a bigger down payment, paying off a small installment loan, or a different program.
4. Assets: the money, and where it came from
The underwriter needs to see that you have the down payment, closing costs and any required reserves, and that the money is yours. On a purchase, that means bank statements covering the most recent full two-month period, all pages. Any single deposit larger than 50% of your monthly qualifying income is a “large deposit,” and its source must be documented or the amount is subtracted from your verified funds. That is the seasoning rule: money that has sat in the account since before the statement window is a balance; money that arrived last week is a deposit with a question attached.
Gift funds are common — 22% of first-time buyers in 2025 used gifts or loans from family or friends for the down payment — and they are fine when documented. The donor must be a relative or someone with a family-like relationship, not the seller, builder or agent. The gift letter must state the amount, that no repayment is expected, and the donor’s name, address, phone number and relationship to you, and the lender must verify that the funds moved. Gifts are not allowed on an investment property, and on a two-to-four-unit home or a second home with less than 20% down you need at least 5% of your own money in the deal. A one-unit primary residence has no conventional reserve minimum; a two-to-four-unit primary residence requires six months of the full housing payment. And 20% down still eliminates private mortgage insurance on a conventional loan.
5. The paper trail: consistency and history
The last thing underwriters check is whether the pieces agree with each other. Names and addresses should match across pay stubs, statements, ID and the credit report; dates on a gift transfer should match the deposit. Where the file has a wrinkle — a late payment, a job gap, an unusual deposit — the underwriter will ask for a letter of explanation. Past derogatory events run on a calendar: conventional guidelines require four years after a Chapter 7 bankruptcy (two with documented extenuating circumstances), two years after a Chapter 13 discharge, seven years after a foreclosure (three with extenuating circumstances), and four years after a short sale or deed-in-lieu (two with extenuating circumstances).
Most of this is now checked electronically: with your authorization, lenders pull payroll and bank data directly, and Fannie Mae’s system can validate income, employment and assets from those reports. That removes paperwork, not standards. Gather what you need with our 2026 mortgage document checklist, and give the underwriter a file that answers its own questions.