How to Source a Large Deposit for a Mortgage

To source a large deposit for a mortgage, give the underwriter a paper trail that proves where the money came from: a bill of sale, a signed gift letter, a settlement statement, or a transfer record from a documented account. Fannie Mae guidelines require lenders to question any single deposit larger than 50 percent of your total monthly qualifying income, so anything above that line needs an explanation and supporting documents.

The cleanest way to see which deposits will get flagged is to convert your statements to a spreadsheet and sort the credits by amount. Anything sitting above the 50 percent threshold is a deposit you should be ready to source before the underwriter asks.

What counts as a large deposit on a mortgage application?

A large deposit is any single credit that exceeds 50 percent of your total monthly qualifying income under Fannie Mae rules. If you earn $8,000 a month, a single $4,001 deposit triggers a sourcing request. Regular payroll direct deposits are excluded; underwriters focus on one-off, non-payroll credits they cannot explain from your income.

How do you source a large deposit?

Sourcing means documenting the origin of the funds so the lender can confirm the money is yours and not undisclosed debt. Match the deposit to a specific event and provide the paperwork for it: the sale of a car, a tax refund, a bonus, gift funds, or a transfer from another account you already disclosed. The document has to show the same amount and date as the deposit.

A filed tax return is one of the easiest sources to evidence, and if you handle your own return you can pull the refund figure straight from the software that read your W-2s and 1099s.

What is deposit seasoning and how long does it take?

Seasoning means letting funds sit in your account long enough that they no longer count as a new large deposit. Most lenders treat money as seasoned after 60 days, because a large deposit only shows up on the two most recent statements they review. If you know a deposit is coming, get it into the account at least two full statement cycles before you apply.

How do you write a letter of explanation for a large deposit?

Keep it short and factual: state the date, the amount, the source, and attach the supporting document. One or two sentences is enough. For example, "The $6,200 deposit on May 3 is proceeds from the sale of my 2019 Honda Civic; the signed bill of sale is attached." Underwriters want the fact and the proof, not a story.

Will a large deposit stop your mortgage?

Rarely on its own. A large deposit almost never sinks an application when you can show a clean, legitimate source. The problem is an unsourced deposit, because the underwriter has to assume it could be borrowed money that adds a hidden payment to your debt-to-income ratio. Document it and the file moves on.

A worked example of a flagged deposit

Suppose your qualifying income is $9,000 a month, so the large-deposit threshold is $4,500. Your two most recent statements show a $12,000 deposit in April and a $3,200 deposit in May. The $12,000 is well over the line and will be questioned; the $3,200 is under it and normally passes without comment. For the $12,000, you pull the settlement statement from selling a rental furnishing lot and a copy of the buyer's wire, both showing $12,000 on the same date it hit your account. That single pairing turns a red flag into a documented, acceptable deposit. The lesson: only deposits above the threshold need sourcing, so you can focus your paperwork on the one or two that matter instead of every credit on the page.

What if you cannot document a large deposit?

If you cannot prove where a deposit came from, the safest move is to leave it out of the funds you rely on for the loan. Underwriters can approve a file while excluding an unsourced deposit from your usable assets, as long as the money you do count is enough for the down payment and reserves. What you should not do is move it around between accounts to hide it, because transfers create a longer trail that underwriters follow, and shuffling money reads as a bigger red flag than the original deposit. Cash is the hardest case of all, so if you keep cash on hand, get it deposited and let it season for at least two statement cycles before you apply.

Gift funds have their own rules

Gift money is allowed on most conventional and government loans, but it needs a specific paper trail: a signed gift letter stating the amount, the donor, the relationship, and that no repayment is expected, plus evidence the donor had the funds and that the money moved to you. For a wire, the letter plus the transfer record usually covers it. Gifts are common for down payments, so lenders have a standard process, but skipping the letter or the donor's bank proof stalls the file just like any other unsourced deposit.

Getting your statements ready for underwriting

Underwriters review your two most recent months of statements for a conventional loan, so the deposits you need to source are the ones on those pages. Convert both months to a spreadsheet, flag every non-payroll credit over the 50 percent line, and gather the document for each one before submission. Self-employed borrowers usually face more of these because business income lands in irregular chunks; the guide to preparing bank statements for a loan and a bank statement analyzer both help you see the file the way the lender will.