Guides / Deposits
How to Source a Large Deposit: A Practical Guide for Purchase Files
Oct 16, 2026 · Varaxon Technologies LLC d/b/a StatementReady
This is educational, not underwriting guidance. Rules below are quoted from specific lender documents as published when checked. Always use the current guidelines for your program.
Article 02 covers how Fannie Mae defines a large deposit. This one is about the next step: the borrower has one, and you need to source it without three rounds of conditions.
Educational summary of Fannie Mae guidance. Non-QM programs have their own rules (see article 11), and lenders may add overlays. Always work from the current Selling Guide and your lender's requirements.
First, confirm you actually need to source it
Under Fannie Mae's Selling Guide B3-4.2-02, all three of these must be true before sourcing is required [1]:
- It's a single deposit over 50% of the total monthly qualifying income for the loan.
- It's a purchase. On a refinance, documentation or explanation isn't required, though the lender must still make sure any borrowed funds, and any related liability, are considered.
- The funds are needed to close, meaning they're used for the down payment, closing costs or financial reserves.
Two more points can take a deposit off the list [1]:
- Only the unsourced portion counts. If part of a deposit is documented, compare only the undocumented remainder with the 50% threshold.
- Some sources are already on the statement. A direct deposit from an employer, the Social Security Administration, an IRS or state tax refund, or a transfer between verified accounts needs no more documentation when the source is printed on the statement, unless there's still a question about whether the funds were borrowed.
What to request, by deposit type
| Deposit looks like | What to ask for | Source |
|---|---|---|
| Gift from a relative | A gift letter signed by the donor that states the actual or maximum dollar amount, says no repayment is expected, and gives the donor's name, address, phone number and relationship to the borrower. Plus evidence of the transfer, such as the donor's check and the borrower's deposit slip, or evidence of the electronic transfer. | [2] |
| Sale of an asset (car, equipment, etc.) | Proof the borrower owned the asset that was sold: Fannie Mae lists "proof of ownership of an asset that was sold" as an example of acceptable documentation. Many underwriters will also want the bill of sale and proof of payment, so ask your underwriter. | [1] |
| Transfer from another account | Statements for the other account, so the transfer is between verified accounts. Then the printed-source exception can apply. | [1] |
| Tax refund, payroll, Social Security | Usually nothing more, if the source is printed on the statement. | [1] |
| Cash or an unclear description | A written explanation from the borrower, plus whatever supports it. If it may be borrowed, expect more scrutiny. | [1] |
Gifts have more rules than the letter alone (acceptable donors, minimum borrower contribution in some cases, and no gifts on investment properties). Check B3-4.3-04 for the full requirements. [2]
When the borrower can't fully document it
Fannie Mae acknowledges that borrowers sometimes don't have every document. In that case the lender uses reasonable judgment based on the available documentation and the borrower's DTI, income and credit profile, and must put its written rationale in the file. Examples of acceptable documentation include the borrower's written explanation and a wedding invitation supporting receipt of gift funds. [1]
If it still can't be sourced, verified funds are reduced by the unsourced amount, and the lender confirms what's left still covers the down payment, closing costs and reserves. That reduced figure is used for underwriting, manual or DU. [1]
Quick test before you chase: subtract the unsourced deposit from the balance. If the borrower still has enough to close and meet reserves, you may not need to source it at all on a Fannie Mae purchase, because the funds aren't needed. Confirm with your underwriter.
On a non-agency loan, why it still matters
Even outside agency guidelines, the federal ability-to-repay rule requires creditors to verify income with reliable third-party records. Its official commentary says a creditor doesn't meet that requirement if it sees "an inflow of funds into the consumer's account without confirming that the funds are income," giving the example of an unidentified $5,000 deposit that might be loan proceeds. [3] That's the reason non-QM underwriters question unusual deposits on income statements, too.
A sourcing workflow that avoids repeat conditions
- List every single deposit above the threshold across all accounts and months you're submitting.
- Strike the printed-source deposits and check whether the remaining funds are needed to close.
- Request documents for what's left in one message, grouped by type, using the table above.
- Re-check partial sourcing: if a document covers only part of a deposit, compare the remainder with the threshold.
Sources (checked 2026-10-15)
Lender rules as published on the sources_verified date; check the current guide before relying on them.
- 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
- Fannie Mae Selling Guide, B3-4.3-04, Personal Gifts: https://selling-guide.fanniemae.com/sel/b3-4.3-04/personal-gifts
- Consumer Financial Protection Bureau, Regulation Z § 1026.43 and official interpretation, comment 43(c)(4)-4 ("Unidentified funds"): https://www.consumerfinance.gov/rules-policy/regulations/1026/43/
This covers Fannie Mae and the federal ability-to-repay rule only. FHA, VA, USDA, Freddie Mac and non-QM programs have their own requirements.
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