Short answer
Because the lender has to confirm your debts and money are what your application says. On Fannie Mae loans, lenders review recent credit inquiries to see whether they led to new debt, ask where large deposits came from, and need papers for any debt on your credit report left off the application. A short, factual letter with supporting documents usually settles it.
Why do they ask about credit inquiries?
An inquiry can mean you opened a new card or loan. Fannie Mae says lenders should look at inquiries to see if they point to debt you didn't list. If you did take on new debt, the application has to be updated and run again. If an inquiry was just shopping for a mortgage or a car you didn't buy, say so.
Why do they ask about deposits?
Fannie Mae calls a single deposit more than half of your monthly qualifying income a large deposit. The lender needs to know where it came from, such as a tax refund, a bonus, the sale of a car or a gift. If it can't be documented, it's left out of the money you can use. FHA uses a similar test: HUD's Handbook 4000.1 requires documentation for any single deposit of more than 50 percent of your total monthly income, and the lender checks that deposits fit your income and savings history and weren't borrowed. FHA also asks for proof of where your earnest money came from if it's more than 1 percent of the price. See where your down payment can come from.
What if a debt on my report isn't really mine to pay?
Any debt with a balance that's left off your application needs papers, for example proof someone else makes the payments or that it was paid off. See co-signed loans and disputed accounts.
How do I write one?
- Keep it short: what happened, when, and the amount.
- Attach proof, such as a receipt, a statement or a gift letter.
- Sign and date it.
Questions like these are routine. Tom can tell you what the underwriter is looking for before you write it.
How can I avoid surprises?
Don't open new credit, move money between accounts without a record, or make big purchases until after closing. See what to do after you apply.
Sources
- HUD Single Family Housing Policy Handbook 4000.1, Update 18 (August 2026), Checking and Savings Accounts; Earnest Money Deposit (TOTAL)
- Fannie Mae Selling Guide B3-5.3-09, DU Credit Report Analysis (inquiries, omitted accounts)
- Fannie Mae Selling Guide B3-4.2-02, Depository Accounts (large deposits)
Checked November 2, 2026. Rules and dates change, so confirm current details before you rely on them.
General information only, not tax or legal advice. Program availability, eligibility and terms vary by lender and are subject to change and to underwriting approval. Not a commitment to lend.