Large Deposit Letter of Explanation for a Mortgage

Quick Answer: A large deposit letter of explanation is a short, signed note telling your mortgage lender where a big deposit on your bank statement came from. For loans sold to Fannie Mae, a deposit is "large" when a single deposit exceeds 50% of your total monthly qualifying income. Name the date, amount, account and source, and attach proof such as a gift letter, a bill of sale or the statement from the account the money came from.

When an underwriter reads your bank statements, every deposit has to make sense. Paychecks and tax refunds explain themselves; a $9,000 transfer from somewhere unlabelled does not. The lender then asks for a letter of explanation: your written account of where the money came from, backed by documents. Writing a clear one, with the right paper attached, is usually the end of it.

What counts as a large deposit?

Lenders set their own overlays, but most conventional loans follow the investor's rules. Fannie Mae's Selling Guide section B3-4.2-02 on depository accounts defines a large deposit as "a single deposit that exceeds 50% of the total monthly qualifying income for the loan". It also says lenders must evaluate large deposits when they use bank statements, which typically cover the most recent two months.

Some quick examples of the threshold:

The test is per deposit. Two transfers of $2,000 each don't add up into one large deposit, though an underwriter can still ask about a pattern that looks odd. FHA, VA and USDA loans have their own rules, and individual lenders may be stricter, so treat your loan officer's request as the definition that applies to you.

When does a lender need an explanation?

For a purchase, Fannie Mae's guide says that when a large deposit is needed for the down payment, closing costs or reserves, the lender must document that the money came from an acceptable source. Three situations change that:

• The source is printed on the statement. If the statement itself shows the deposit came from an employer's payroll, the Social Security Administration, an IRS or state tax refund, or a transfer between accounts the lender has already verified, no further explanation or documentation is needed.
• The funds aren't needed. If the lender can't document a deposit, the guide says verified funds are reduced by that amount, and the lender confirms whether what is left is enough. You may still be asked about it; it simply stops counting toward your assets.
• It is a refinance. For refinances, documentation or explanation of large deposits is not required, but the lender is still responsible for spotting borrowed money and any debt that comes with it.

What should a large deposit letter of explanation include?

Underwriters read dozens of these. The good ones are short, factual and easy to match to the statement. Include:

1. Your full name, the loan or application number, and the date.
2. The bank, the account type and the last four digits of the account.
3. The date and exact amount of each deposit being explained, as they appear on the statement.
4. Where the money came from, in one or two plain sentences.
5. A list of the documents you are attaching.
6. Your signature, and your co-borrower's if the account is joint.

Leave out anything you can't back up, and don't round the amount.

A sample letter

Re: Loan application 0045-1187

>

On 12 August 2026 I deposited $8,400.00 into my Example Bank checking account ending 3307. The money came from the sale of my 2017 Honda Civic to a private buyer, who paid by cashier's check. I have attached the signed bill of sale, a copy of the title transfer, a copy of the cashier's check, and my August statement with the deposit highlighted.

>

Signed, Jordan Example, 20 August 2026

Write a separate paragraph for each deposit if you have more than one.

Which documents prove the source?

The letter states the source; the documents prove it. Fannie Mae's examples of acceptable documentation include the borrower's written explanation, proof of ownership of an asset that was sold, and even a copy of a wedding invitation to support wedding gift money. Match the evidence to the type of deposit:

If the money moved through more than one account on the way, document each step. A deposit from your own savings account is only as good as the savings statement showing where that money came from.

What mistakes get a letter sent back?

Underwriters return letters that leave them with a new question. The usual problems:

• The amount doesn't match. You wrote $8,400 but the statement shows $8,400.17 because a small transfer posted the same day. Copy the figure from the statement.
• The source is vague. "Savings" or "family help" invites a follow-up. Say which savings account, or which relative, and how the money moved.
• The documents don't connect. A gift letter without proof the donor actually sent the money, or a bill of sale with a different amount from the deposit, will trigger another request.
• Only one borrower signed. If the account is joint, or both of you are on the loan, both should sign.
• A new unexplained deposit appears. When the lender asks for an updated statement before closing, any fresh large deposit starts the process again.

Answer only what was asked. Extra explanations about deposits nobody queried can create questions that weren't there before.

How do you avoid large-deposit questions in the first place?

• Move down-payment money into the account you'll use well before you apply, ideally before the statement periods the lender will review, and keep the trail.
• Deposit gift money by transfer or check rather than in cash, and get the gift letter signed at the same time.
• Don't make unusual transfers between your accounts during the application.
• Keep your own list of every deposit over the threshold, with its source, as you go.

That last list is easy to build from statement PDFs. Convert the two or more statements the lender asked for into a spreadsheet, sort by amount and flag anything above half your monthly income; QuickBankConvert does the conversion without a bank login and shows the opening and closing balance with the rows, and a free account downloads Excel or CSV. Send the lender the original statements, not the spreadsheet.

Related guides

• How many bank statements you need for a mortgage
• How lenders analyze bank statements
• Bank statements for a loan application

This page explains documentation; it is not lending advice. Your lender's requirements apply to your loan.