Guides / Deposits
Fannie Mae Large Deposit Rule: The 50% Calculation, Explained
Oct 16, 2026 · Varaxon Technologies LLC d/b/a StatementReady
This is a summary for education. Always work from the current Selling Guide and your lender's overlays.
Large deposits are one of the most common conditions on purchase files. Fannie Mae's rule is short and specific. Here's what it says and how to apply it, with every point taken from the Selling Guide section on depository accounts (B3-4.2-02). [1]
The definition
"A large deposit is defined as a single deposit that exceeds 50% of the total monthly qualifying income for the loan." [1]
So the calculation is:
Large-deposit threshold = total monthly qualifying income × 50%
Any single deposit above that amount is a large deposit. For a borrower qualifying on $8,000/month, the threshold is $4,000.
It's measured against the total monthly qualifying income for the loan, not one borrower's income. It also applies to single deposits, not a month's total.
When you have to do something about it
Per Fannie Mae, the requirements depend on the transaction type. [1]
| Transaction | What's required |
|---|---|
| Refinance | Documentation or explanation for large deposits is not required. The lender is still responsible for making sure any borrowed funds, including any related liability, are considered. |
| Purchase | If funds from a large deposit are needed to complete the purchase (down payment, closing costs or financial reserves), the lender must document that they come from an acceptable source. |
On a purchase, if a large deposit can't be documented, verified funds have to be reduced by the unsourced amount. The lender then confirms the remaining funds still cover the down payment, closing costs and reserves. [1]
Only the unsourced portion counts
When part of a deposit is documented, only the unsourced part is compared with the 50% threshold. [1]
Fannie Mae's own example uses a borrower earning $4,000/month, so the threshold is $2,000:
- Scenario 1: a $3,000 deposit, of which $2,500 is documented as a federal tax refund. The unsourced $500 is 12.5% of income, so it's not a large deposit. The full $20,000 balance can be used. [1]
- Scenario 2: the same $3,000 deposit with only $500 documented. The unsourced $2,500 is 63% of income, so it is a large deposit. Only $17,500 of the $20,000 balance can be used. [1]
Deposits that don't need more documentation
If the source is readily identifiable and printed on the statement, the lender doesn't need further explanation or documentation. Fannie Mae's examples [1]:
- a direct deposit from an employer (payroll)
- the Social Security Administration
- an IRS or state income tax refund
- a transfer of funds between verified accounts
If there's still a question about whether the funds were borrowed, get more documentation anyway.
DU validation
When assets are validated through DU's validation service, DU issues a message listing which large deposits need documentation. Following those messages satisfies the requirement. [1]
A quick checklist for purchase files
- Confirm total monthly qualifying income for the loan.
- Threshold = income × 50%.
- Scan every statement for single deposits above the threshold.
- Remove deposits whose source is printed on the statement (payroll, SSA, tax refund, transfers between verified accounts).
- For the rest, decide whether the funds are needed to close. If they are, request documentation (for example a letter of explanation or proof of an asset sale).
- If a deposit stays unsourced, reduce verified funds by the unsourced amount and recheck that the borrower has enough to close.
Try it
- Prefer to check by hand? See How to Spot Large Deposits on Bank Statements by Hand.
Every statement is reconciled to its printed opening and closing balances. Anything that doesn't tie out, or can't be checked, is flagged for your review.
StatementReady assists your review. It doesn't make underwriting or credit decisions, and it doesn't replace your judgment or your lender's guidelines.
NFCU checked on real files; other US banks and credit unions are accepted, checked to the cent, and marked Unverified if a statement doesn't reconcile or can't be checked.
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Source (checked 2026-10-15)
- Fannie Mae Selling Guide, B3-4.2-02, Depository Accounts ("Evaluating Large Deposits"): https://selling-guide.fanniemae.com/sel/b3-4.2-02/depository-accounts
This covers Fannie Mae only. FHA, VA, USDA, Freddie Mac and non-QM programs have their own rules.
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