Somewhere between application and closing, many borrowers get a note from their loan officer asking for a “letter of explanation” — LOX or LOE in mortgage shorthand. It is not a bad sign. It means the underwriter found something the documents do not explain on their own and wants you to fill the gap in writing. Handle it well and the request costs you an afternoon; handle it badly and it can stall the file for weeks.

Why underwriters still ask, even with automated approvals

Most conventional loans run through an automated underwriting system, and lenders can now verify income, employment and assets electronically, pulling payroll and bank data with your authorization. That cuts paperwork, but it does not remove the human step: the automated finding comes back with conditions an underwriter must clear, and when a condition is “explain this,” the software cannot answer for you. Large deposits, credit inquiries and employment gaps still generate letter requests in 2026.

The five common triggers

1. Overdraft or insufficient-funds charges. On a purchase, the lender reviews your most recent full two months of bank statements, and every fee line is visible. Repeated overdrafts suggest a household running close to the edge. If yours were a one-time event, say so, explain the cause, and note what changed.

2. Late payments or collections. Payment history is the single largest component of a FICO score, so an otherwise clean file with one or two late payments gets a question. The underwriter wants the date, the account, the reason, and evidence that the account is current now. If the event was a bankruptcy or foreclosure, the calendar matters more than the letter: conventional guidelines impose waiting periods — generally four years after a Chapter 7 bankruptcy and seven years after a foreclosure, shorter with documented extenuating circumstances — and your letter is where those circumstances get documented.

3. Address or name discrepancies. Every document in the file should show the same person at the same address. A bank statement mailed to a parent’s house, a pay stub under a former name or a credit report listing an address you never lived at all draw a request. State which address is correct, explain why the other appears, and attach any document (a lease, a marriage certificate) that ties the two together.

4. Employment gaps. Lenders evaluate your most recent two years of employment, and any gap inside the most recent twelve months has to be analyzed. FHA guidelines treat an absence of six months or more as an extended gap and generally want you back at work for at least six months, with a two-year work history before the break. Whatever the reason, give the dates, the reason, and the date you started your current job. Underwriters are judging the likelihood that your income continues, not the gap itself.

5. Large deposits. Fannie Mae defines a large deposit as a single deposit exceeding 50% of your total monthly qualifying income. On a purchase, the lender must document the source of any large deposit you are counting toward the down payment, closing costs or reserves, or else subtract the unexplained amount from your verified funds. An unexplained lump sum might be a loan you will have to repay, or a gift that needs its own paperwork. Deposits whose source is obvious on the statement — payroll, Social Security, a tax refund, a transfer between your own verified accounts — need no letter at all.

Lenders commonly list other triggers too: recent credit inquiries (the underwriter must confirm you have not taken on new debt missing from your application), gift funds, a past bankruptcy or foreclosure, and ownership of several properties. The same letter structure works for all of them.

What the underwriter actually wants

  • Facts, not a story. Dates, amounts, account names and what happened. Skip the apology and the character reference.
  • Brevity. Lenders commonly suggest about 100 to 200 words: one sentence of context, the facts, one sentence to close.
  • A conclusion the underwriter can write down. “The funds are from the sale of my car; no repayment is expected.” “The account is current and has been since the missed payment was caught up.”
  • Attachments. A bill of sale, a canceled check, a separation notice from a former employer or a gift letter signed by the donor does more than any prose.
  • Consistency. The letter must match the rest of the file. A different date or amount creates a second question.
  • Your signature and the date. Every borrower on the loan should sign a letter that concerns them.

Ask your loan officer to read it first; they know what their underwriters accept.

A short template

Date

To: Underwriting department, followed by your lender’s name and your loan number

Re: Explanation of the deposit to my checking account shown on my most recent statement

I am writing to explain the deposit to my checking account that appears on the enclosed statement. The funds are the proceeds of the sale of my car to a private buyer. I have attached the bill of sale and a copy of the buyer’s cashier’s check, which match the deposit amount and date. No part of this deposit is a loan, and no repayment is expected.

Please contact me if you need anything further.

Your signature, printed name, current address and phone number

Swap the middle paragraph for whichever trigger applies: the dates and reason for an employment gap, the account and cause of a late payment, the correct address and why another one appears. Keep it short and attach the proof.

Head off the request before it comes

The best letter is the one you never have to write. Before you apply, pull your free weekly credit reports from all three bureaus at AnnualCreditReport.com and fix any errors. Move down-payment money into the account you will document early enough that it shows up as a balance rather than a deposit inside the two-month statement window. If a relative is helping, get the gift letter signed up front: it must state the dollar amount, that no repayment is expected, and the donor’s name, address, phone number and relationship to you. Do not open new credit while the loan is in process. Our 2026 mortgage document checklist covers what to gather, and what underwriters actually check explains how it is read.