Mortgage Broker Document Checklist: Validate the File

A mortgage broker needs, for every applicant, proof of identity, proof of address, proof of income, three months of bank statements, evidence of the deposit and its source, and details of existing credit commitments. The checklist only becomes useful when each item is also checked for completeness, validity (dates and expiry) and consistency with the other documents in the file. That second layer is what stops a case bouncing back from underwriting after the decision in principle.

This article is for informational purposes only and does not constitute legal, financial, or regulatory advice. Regulatory references are accurate as of the publication date. Consult a qualified professional for guidance specific to your situation.

What documents does a mortgage broker need from a client?

A broker needs identity, address, income, bank, deposit and commitment documents, with the exact income evidence depending on whether the applicant is employed, self-employed or a company director. Lenders publish slightly different lists, but the core is stable.

Under MCOB 11.6, a lender must check that a mortgage is affordable and take reasonable steps to verify the applicant's income, which is why every lender's checklist is built around income and outgoings evidence (FCA Handbook, MCOB 11.6). The broker's job is to hand over a file that satisfies that check on the first read.

Santander's published guidance, for instance, asks for a payslip dated within two months of the application and accepts either an accountant's certificate or SA302 forms for the self-employed (Santander, documents for a mortgage). Treat any such list as a starting point and confirm the specific lender's criteria before the client gathers anything.

How do you check that each document is complete?

A document is complete when every page is present, every required field is readable and the figures needed for the affordability model can be read from it. Missing pages are the most common reason for a chaser email.

Run these completeness checks on every upload:

1. All pages of a bank statement. A statement that jumps from page 1 of 3 to page 3 of 3 hides transactions the underwriter will want to see.
2. Full payslip. Employer name, employee name, pay date, gross and net pay, tax code and year-to-date figures should all appear.
3. Full tax document. An SA302 without its matching tax year overview is often rejected.
4. Both sides of a photocard licence where the lender requires the paper counterpart details.
5. Signed gifted deposit letter that names the donor, the amount and states that no repayment is expected.

A tick box on a checklist is not enough here. The check is whether the page actually contains the field, not whether a file with the right name was uploaded.

Which dates and expiry rules cause rejections?

Date rules cause rejections because lenders set recency windows and a file can fall outside them while the broker is still collecting documents. The case is valid on day one and stale by day thirty.

• Payslips commonly need to be dated within the last two months at the time of application.
• Bank statements usually need to cover the three most recent complete months, so a case sitting for weeks needs refreshed statements.
• Identity documents must be in date. A passport that expires inside a few months can prompt questions.
• Proof of address such as a utility bill is typically accepted if dated within three months.
• Mortgage illustration and decision in principle have their own validity periods, after which the lender may re-run checks.

Build a "stale by" date into the case record: the earliest date among all documents plus the lender's window. A file that crosses that date goes back to the client before it goes to the lender.

Which cross-document checks catch the problems underwriters find?

Cross-document checks compare the same fact across several documents, and a mismatch is what makes an underwriter stop and ask. They matter more than any single document, because each document can be correct on its own.

The net pay reconciliation is the one that catches most brokers out. The payslip says one number, the salary credit three weeks later says another, and the difference is a salary sacrifice, student loan deduction or a pension change nobody mentioned. Our article on cross-document validation beyond OCR explains why reading each file in isolation misses these comparisons.

A comparison of fields tells you the file is consistent. It does not prove any document is genuine, and a validation step should never be described as doing so.

Source of funds and AML: what the broker is responsible for

Mortgage intermediaries are within scope of the UK Money Laundering Regulations, which means customer due diligence and, where the deposit is large or unusual, an understanding of where it came from. The relevant rules are in the Money Laundering Regulations 2017, and the FCA supervises mortgage intermediaries' compliance with them.

In practice the deposit file should show where the money sat, for how long, and who paid it in. Typical triggers for a closer look: a lump sum credited in the last month, a deposit from a third party, funds from overseas, or the proceeds of a property sale with no completion statement. For gifted deposits, the donor's identity and the gift letter belong in the file.

What do brokers and borrowers actually ask about the checklist?

Forum threads from brokers and first-time buyers circle around the same few questions, and the answers are rarely in the lender's glossy checklist.

"The lender asked for more documents after the decision in principle. Why?" A DIP is usually a soft assessment based on declared figures. The full underwrite compares the declared figures with documents, so any mismatch that was invisible at DIP stage appears now. Validating before the DIP is cheaper than answering queries after it.

"How recent do payslips and statements have to be?" It depends on the lender, but two months for payslips and the latest three complete months for statements are common. Ask the lender, then record the window in the case notes.

"Do I need original documents or are PDF downloads fine?" Most lenders accept online banking PDFs and screenshots of mobile statements are often refused. Check whether the lender wants statements that show the account holder name and account number in the header.

"My client changed jobs six weeks ago. Is that a problem?" Often it is a documentation problem rather than a policy one: a new contract, a signed offer letter and a first payslip, or a probation period confirmation, change the picture. The checklist for a recent starter is longer than the checklist for someone with five years' service.

A validation routine you can run before every submission

Run the same four steps for every case, in the same order, so that nothing depends on who is handling the file that day.

1. Collect against a lender-specific checklist, not a generic one.
2. Check completeness of each upload: pages, fields, signatures.
3. Check validity: dates against the lender's windows, expiry on identity documents.
4. Check consistency: names, addresses, employers, net pay and deposit figures across the file.

Brokers who handle dozens of cases a month tend to find that manual checking works for the first two steps and fails on the fourth, because comparing six documents by eye is where people skip. This is where an automated check helps: it extracts the named fields and compares them across documents, and flags only the differences. For firms that place credit and mortgage files with lenders, our financing and leasing solution describes how that comparison is configured, and the pricing page shows the cost per file. Details on data handling are on the security page. For the wider picture across sectors, see the industry verification guide, and for the consumer credit equivalent read income document validation before a credit decision.

Frequently asked questions

What is a mortgage broker document checklist?

It is the list of documents a broker collects from an applicant before submitting a case: identity, address, income, bank statements, deposit evidence and existing commitments. A good checklist also records the date window for each item, so stale documents are caught before submission.

What documents do mortgage lenders require?

Lenders require proof of identity, proof of address, proof of income (payslips and P60, or SA302 forms for the self-employed), recent bank statements and evidence of the deposit. Exact requirements differ by lender and by applicant type, so check the lender's criteria for each case.

How many months of bank statements does a mortgage broker need?

Three months of current account statements is the most common requirement, and some lenders ask for six months for self-employed applicants or where income is variable. The statements should cover the most recent complete months and show the account holder's name.

How can a broker reduce back-and-forth with underwriters?

Check the file for completeness, date validity and cross-document consistency before submission. Most chasers trace back to a missing page, an out-of-date payslip or a net pay figure that does not match the bank statement.