Five million people have too thin a credit file to be judged fairly

Five million UK adults have what lenders call a "thin" credit file. This does not mean it is a bad credit file, just a short one. No missed payments, no defaults, nothing wrong on paper because the problem is that there is barely any paper at all. A thin file usually means one of three things: you are young and have not borrowed much yet, you have paid for most things in cash or on a debit card, or you have arrived in the UK recently and have no domestic borrowing history at all. None of that says anything about whether you can afford a mortgage, it just means the traditional scoring model has nothing to work with.

What a thin file actually means

Your credit file is a record held by the credit reference agencies of how you have borrowed and repaid money in the past: credit cards, loans, mobile contracts, overdrafts. A thin file simply has very little of that history in it. It is not a red flag, it is an absence of data and lenders have historically treated the two as if they were the same thing.

Why the traditional score gets this backwards

Traditional scoring rewards a track record of borrowing and repaying, not a track record of managing money well. A customer who has never taken out a loan can look, on paper, less predictable than a customer who has taken out five and paid four of them off late. That is backwards, and it is the reason so many genuinely low risk customers get declined or offered worse rates than they deserve.

What this looks like for two real customers

Take two customers applying for the same mortgage on the same salary. One has three credit cards, a car loan and a patchy repayment history. The other has never borrowed a penny, paid cash for their last car and has a spotless bank account. Under a traditional score, the first customer often looks like the safer bet because there is more repayment history to point to, even if some of it was late. The second customer, the one with no borrowing history at all, is the one traditional scoring struggles with most, not because anything is wrong, but because there is nothing to measure.

Open banking changes what gets measured. Instead of asking what you have borrowed before, it looks at what you actually do with the money you have: whether income lands consistently, whether spending stays within it and whether a savings buffer is being built. On that measure, the second customer is often the stronger case, not the weaker one.

What open banking shows instead

Open banking, with customer consent, lets a lender look past the file entirely. Instead of inferring affordability from borrowing history, they can see real income, real spending and real savings behaviour, direct from a bank account. A customer who has never missed a rent payment, built a savings buffer and spent within their means for two years running is a good credit risk, whether or not a credit reference agency has enough history to say so.

A thin file is not the same as a bad file

It is worth being direct about this distinction, because the two get treated as interchangeable more often than they should. A bad file means missed payments, defaults or a history of borrowing more than you could manage; that is a real signal about risk. A thin file means none of that history exists yet, in either direction.

Lenders that rely purely on a credit score cannot always tell the difference between the two at a glance, because a thin file and a genuinely poor file can both produce a below-average score. Open banking resolves that ambiguity directly. A lender looking at, potentially up to 24, months of real transactions can see immediately whether the account behind a thin file is healthy or under strain, rather than guessing from a number that was never built to distinguish between the two.

Who this matters most for

This affects four groups more than most: young first-time buyers, people who have avoided debt on principle, returning expats and anyone new to the UK. So the customers most likely to be unfairly scored are often the ones most ready to take on a mortgage responsibly.

How lenders and brokers actually use this data

A soft credit check still happens alongside an open banking review; the two are complementary, not competing. The credit file confirms there is nothing adverse historically. Open banking then does the remaining work, showing income, spending and saving behaviour in enough detail for a lender or broker to make a confident decision without waiting for a thicker file to build up over years.

This matters as much for a first-time buyer building credit from nothing as it does for someone new to the UK with an established financial history abroad that simply has not registered here yet. Neither customer is a worse credit risk for the gap; both just need a lender willing to look at the fuller picture instead of labelling a case as "too difficult".

A thin file only ever tells a lender what is missing from your history, never what is actually true about your day-to-day finances right now. Checking your mortgage readiness before you apply replaces that gap with a real picture, built from your own data.

What you can do right now

• Check your file with the credit reference agencies so you know what a lender will see before you apply.
• Ask whether your broker or lender offers open banking verification; not all do yet.
• Run an open banking affordability check before you approach a lender or broker; it gives you the same picture they will eventually see, with time to act on anything it flags.
• If you are applying jointly, remember a thin file on one side does not have to drag the whole case down; a strong combined picture can carry a thin individual file.
• If your file is thin, say so plainly and explain why; a lender who understands the reason is far more likely to look at the fuller picture instead of the gap.

A thin file is not a black mark. It is a data problem, and data problems have a fix.

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Frequently asked questions

What counts as a thin credit file?

A thin file usually means fewer than two or three active credit accounts, or accounts opened too recently to show much history. It is common among young adults, people who avoid borrowing, and anyone new to the UK.

Does a thin file mean I have bad credit?

No. A thin file simply means there is not much history to score, in either direction. It is different from a poor file, which reflects missed payments or defaults that have actually happened.

Can I get a mortgage with no credit history at all?

Yes, though fewer mainstream lenders will consider it without extra evidence. Open banking gives a lender a real picture of income and spending to assess affordability without relying on a score built from borrowing history alone.

Will an open banking check affect my credit file further?

No. Open banking works alongside a soft credit check, which leaves no mark on your file and is not visible to other lenders.

How long does it take to build up a thicker credit file?

Typically one to two years of active, well-managed credit use, though this varies. Open banking is useful precisely because it does not require you to wait that long.

Is a thin file more common for certain groups?

Yes; it disproportionately affects young first-time buyers, people who have deliberately avoided debt, returning expats and anyone new to the UK, none of whom are inherently higher risk.

Do all lenders accept open banking data for thin-file applicants?

Not yet universally, though adoption is growing quickly. A broker who knows which lenders take open banking data seriously can make a real difference to a thin-file case.

Should I mention my thin file in my application?

Yes. Explaining the gap plainly, rather than hoping it goes unnoticed, makes it easier for a lender or broker to look past it to the fuller financial picture.

What's the difference between a thin file and no file at all?

In practice, very little; both describe an account with too little borrowing history for a traditional score to work with confidence. A file with one closed mobile contract from years ago and a file with nothing on it at all tend to get treated the same way by lenders who rely on the score alone.

Does paying rent on time help build a credit file?

It can, if your landlord reports payments to a rent recognition scheme, though many do not. This is exactly the gap open banking fills in the meantime; a lender can see the rent leaving your account every month even if it never reaches your official credit file.