Quick Answer: A CPA’s expense factor letter is built around disclaimers: that the figures come from your own records and were not audited, that it covers a stated period, that it reports only the expense ratio (not your income, affordability, or solvency), that it is for the named lender alone, and that past expenses don’t guarantee future results in 2026.
This article reflects federal rules, AICPA professional standards, and non-QM lender practices as of June 2026. Lender programs and guidance change — confirm current requirements with your CPA and loan officer before you rely on them.
On a bank-statement mortgage, the lender doesn’t read your tax returns. It adds up your business deposits and assumes a chunk of them — often 50% — went to expenses, then treats what’s left as income. A CPA’s expense factor letter can replace that flat 50% assumption with your business’s real, usually lower, expense ratio. That single number can move your approval by tens of thousands of dollars, which is exactly why the CPA wraps it in careful disclaimers.
About 16.6 million Americans were self-employed as of late 2025, and many turn to bank-statement loans precisely because their write-offs make their tax returns look lean. The disclaimers are not fine print to skim past. They are what let a CPA put a number a lender relies on in writing at all — and they tell you exactly what the letter does and does not promise.
Here is what you will learn:
- 🧾 What an expense factor (expense ratio) letter is, and how a lender uses it
- ⚖️ Each disclaimer a CPA includes — and the precise risk it manages
- 🧮 A worked example showing how your expense ratio swings qualifying income
- 🚫 What the letter deliberately does not say (income, affordability, the future)
- 🔗 How the disclaimers tie to lender reliance and the limits of a CPA letter
What an Expense Factor Letter Actually Is
Before the disclaimers make sense, you need to see the job the letter does. It is a narrow document with an outsized effect on a single kind of loan.
A bank-statement loan is a non-QM mortgage built for self-employed borrowers. Instead of tax returns, the lender uses 12 to 24 months of business bank deposits to estimate income. Because gross deposits aren’t profit, the lender backs out an “expense factor” — a percentage assumed to cover the cost of running the business. Left to its default, that factor is commonly 50%, a blunt one-size-fits-all guess.
An expense factor letter is a CPA’s written statement of your business’s actual expense ratio, drawn from your books. If your real expenses run 35% of revenue rather than 50%, the letter tells the underwriter to use 35% — which leaves more deposits counted as income. Programs vary, but many will accept a CPA-certified ratio well below the 50% default, with floors that differ by lender.
Why does this gap exist at all? The default 50% is deliberately conservative because the lender knows nothing about your specific costs. A graphic designer working from a laptop, a bookkeeper, or a consultant may spend far less than half of revenue on the business, yet the flat factor treats them like a restaurant or a contractor with heavy materials and payroll. The letter exists to replace that worst-case assumption with the truth about your business — but only the truth, which is why the CPA can certify a lower ratio your records support and never a number invented to win a bigger loan.
It helps to picture how the lender reviews your deposits. The underwriter pulls 12 or 24 months of business bank statements, adds up the qualifying deposits, and often strips out anything that doesn’t look like revenue — transfers between your own accounts, loan proceeds, one-time refunds. Then it applies the expense factor to what remains. If you run a personal-account program instead, the math shifts again. The expense factor letter plugs into the one variable a CPA can credibly speak to: the share of genuine business deposits that ordinary operating costs consume.
The letter is not an audit, a tax return, or an income certification. It answers one question — what share of your deposits are business expenses — and the disclaimers exist to keep it answering only that question. The consequence of an over-broad letter is real liability for the CPA, so the limiting language is not optional; it is the price of writing the number down.
Illustrative letter. The certified ratio is one line; the rest is the disclaimers that make it signable.
The Disclaimers, One by One
Each disclaimer manages a specific risk. Read them as a set: together they let the CPA state a useful number without taking on duties they never performed.
“Based on records you provided; not audited or verified.” Your CPA derives the ratio from your books and returns — information you supplied. They did not audit it. This disclaimer mirrors the AICPA position that tax work relies on client representations that are neither audited nor verified. Without it, a stray error in your records becomes the CPA’s problem.
“Covers the period [dates].” The ratio is tied to the same window as your bank statements — say, the trailing 12 months. Expenses shift over time, so the CPA pins the figure to a defined period rather than implying it is permanent.
“Reports the expense ratio only.” The letter states a percentage. It does not verify your income amount, certify you can afford the payment, or opine on whether the business is solvent. Those are separate questions the CPA was not engaged to answer.
“Not an attestation or assurance engagement.” Providing formal assurance triggers the AICPA’s attestation standards. By stating the letter is not an audit, review, or examination, the CPA makes clear they are reporting an observation, not issuing an opinion that would require those procedures.
“For [named lender] only; no third-party reliance.” The letter is addressed to one lender for one loan. This limits who can rely on it and is the CPA’s main defense against an open-ended duty to strangers — the seed of lender reliance liability that a careless letter creates.
“Past results don’t guarantee future expenses.” A historical ratio is not a forecast. The business could change; the CPA disclaims any promise about what the ratio will be next year.
“Provided with the client’s written consent.” Because the letter discloses information drawn from your tax records, the CPA needs your IRC §7216 authorization before sending it. The disclaimer documents that consent exists.
Illustrative. Read as a set, the disclaimers let the CPA state a useful number without taking on untested duties.
A common misconception is that all this hedging weakens the letter. It does the opposite. A disclaimer-free letter is one most CPAs simply won’t sign, so the limiting language is what turns “I can’t put my name on that” into a number your lender can use.
Why the Disclaimers Protect You, Too
It is easy to read the disclaimers as the CPA covering themselves at your expense. In practice they protect your loan as much as the accountant.
Start with credibility. An underwriter who sees a clean, scoped letter — actual ratio, stated period, named methodology — trusts it precisely because it doesn’t overreach. A letter that claimed to “verify income” or “guarantee” your business would draw scrutiny, because no honest CPA can promise those things from a books review. The restraint is what makes the number believable, and a believable number is what gets used.
Then consider speed. A letter loaded with assurances the CPA can’t support is one their malpractice insurer may flag, which slows or stops it. A properly scoped letter sails through, because nothing in it exceeds what the CPA actually did. On a closing clock, that difference is days.
Finally, the disclaimers keep your letter reusable and honest. Because it states a real ratio for a real period, it holds up if a second underwriter or a quality-control reviewer looks again. A stretched letter that quietly shaved your ratio or implied more than the records support is the kind of document that unravels late — after the appraisal, after the rate lock — when it is most expensive to lose. If you’d rather not navigate that line yourself, Tax Shark’s CPA letter service certifies a ratio your records support and words it so it survives a second look.
A Worked Example: How the Ratio Moves Your Income
The disclaimers protect the CPA, but the ratio is what changes your loan. Here is the math the letter feeds.
Sample figures, 100% ownership. The CPA certifies the ratio only; the lender computes the income.
Say your business deposits average $30,000 per month over the past 12 months, and you own 100% of the business. Under the lender’s default 50% expense factor, half of that is assumed to be expenses, leaving $15,000 per month in qualifying income. Now suppose your CPA reviews your books and certifies a 35% expense ratio. The lender keeps 65% instead of 50%: $30,000 × 0.65 = $19,500 per month in qualifying income. That is $4,500 more per month of income the underwriter can use — often the difference between approval and denial, or between the house you wanted and the one you settled for. The letter cost a few hundred dollars; the ratio change can lift your borrowing power by tens of thousands.
Ownership changes the picture too. If you owned only 60% of the business, the lender would count 60% of that income — $11,700 instead of $19,500 — because you can only claim your share. The CPA’s letter notes your ownership percentage as a fact from the records, but it still doesn’t compute your final qualifying income; it hands the lender the inputs and lets underwriting do the arithmetic.
Notice what the CPA did and did not do. They reported the expense ratio from your records. They did not certify the $19,500, decide whether you qualify, or promise the ratio will hold next year. The disclaimers draw exactly that line.
Which Situation Applies to You?
The letter only matters on certain loans, and only helps in certain cases. Find your row.
- Bank-statement loan, low real expenses: This is the sweet spot. A CPA-certified ratio below the default 50% raises your income — worth far more than the letter costs.
- Bank-statement loan, expenses near 50%: A letter may not help much; if your true ratio is close to the default, there’s little to gain.
- Conventional or agency loan: These use tax returns, not an expense factor. An expense factor letter doesn’t apply; you’ll provide returns or transcripts instead.
- You don’t have a CPA who knows your books: A CPA can still write the letter after reviewing your records, or a specialist service can — expect a short review first.
- Lender names a floor below your real ratio: The CPA certifies your actual ratio; they won’t state a lower number just to hit the lender’s floor.
The throughline: the letter helps only when your genuine expense ratio is meaningfully below the default, and only on loans that use one.
How to Get an Expense Factor Letter
The process is short, but the order protects both you and the CPA. Work it in sequence.
The short path to a certified expense ratio — only on loans that use one.
The first move is to confirm the loan even uses an expense factor. Ask your loan officer whether it’s a bank-statement program and what default factor and floor apply. On an agency loan, stop — you need returns instead.
The second move is to sign the consent. Your CPA needs a written §7216 authorization before reviewing your records for this purpose or sending anything to the lender.
The third move is to let the CPA review your books and derive the ratio. They’ll examine your records for the same period as your bank statements and calculate the expense percentage with a stated methodology.
The fourth move is to deliver the letter with its disclaimers intact. The scope-and-limits language is not negotiable filler; it is what lets the CPA certify the number. Keep a copy, and give the lender the version addressed to them.
Three Common Scenarios
Scenario 1 — Renata, the low-overhead consultant
Renata’s lender defaulted to a 50% expense factor, cutting her qualifying income in half.
| What Renata faced | How it resolved |
|---|---|
| Default 50% factor halved her income | CPA reviewed books and certified a 30% ratio |
| She feared the letter overreached | It stated the ratio only, with full disclaimers |
| Approval was borderline | The higher income cleared her debt-to-income ratio |
Scenario 2 — Theo, asked to certify income
Theo’s lender sent a template asking his CPA to “verify monthly income,” not just the ratio.
| What Theo faced | How it resolved |
|---|---|
| Template asked for income certification | CPA declined; the letter reports the ratio, not income |
| Lender needed a usable figure | CPA’s ratio let the lender compute income itself |
| Disclaimers seemed to weaken it | Underwriting accepted the scoped letter as written |
Scenario 3 — Bianca, on a conventional loan
Bianca asked for an expense factor letter, but her loan was a standard conforming mortgage.
| What Bianca faced | How it resolved |
|---|---|
| Wanted an expense factor letter | Conventional loans don’t use one |
| Loan ran on tax returns | She provided two years of returns and transcripts |
| Still wanted CPA support | CPA confirmed her self-employment existence instead |
Mistakes to Avoid
- Asking the CPA to drop the disclaimers. A letter without scope-and-limits language is the one a CPA won’t sign — pushing on it just kills the letter.
- Requesting a ratio below your real one. A CPA certifies actual expenses; asking them to understate the ratio to hit a lender floor is asking them to misrepresent.
- Assuming the letter verifies your income. It reports a percentage, not a dollar figure; the lender still computes income and decides if you qualify.
- Using it on the wrong loan. Conventional and agency loans use tax returns, not an expense factor — the letter does nothing there.
- Sending records without a §7216 consent. That exposes the CPA to penalty and stalls the file.
- Treating the ratio as permanent. It covers a stated period; a letter implying it will never change invites trouble for the CPA.
- Expecting the CPA to certify affordability. That’s the lender’s debt-to-income decision, and the letter disclaims it.
- Shopping for the CPA who’ll state the lowest number. Underwriters and insurers scrutinize unusually low ratios; an unsupported figure can sink the file and the CPA.
Do’s and Don’ts
Do confirm the loan is a bank-statement program before ordering the letter, because only those use an expense factor.
Do sign the §7216 consent promptly, since the CPA can’t review records or send the letter without it.
Do give the CPA the same period your bank statements cover, so the ratio lines up with the deposits.
Do keep the disclaimers in the letter, because they’re what make the number signable.
Do expect a professional fee, as a reviewed, certified ratio is a real engagement.
Don’t ask the CPA to omit the limiting language or shave the ratio below reality.
Don’t treat the letter as proof of income — it’s a ratio, not a dollar amount.
Don’t assume it helps on a conventional loan; those run on returns.
Don’t wait until the last minute, because the review takes a day or two.
Don’t expect the letter to guarantee approval — qualification is the lender’s call.
Pros and Cons of an Expense Factor Letter
Pros
- It can raise your income sharply. A real ratio below the default 50% counts more of your deposits as income.
- It’s affordable relative to the gain. A few hundred dollars can unlock tens of thousands in borrowing power.
- It’s signable. Because it reports one fact with disclaimers, a CPA can issue it without crossing a rule.
- It’s narrow and low-risk. Reporting a ratio carries far less exposure than verifying income.
- It fits the loan. Bank-statement programs are built to accept exactly this letter.
Cons
- It only helps on some loans. Conventional and agency loans don’t use an expense factor.
- It needs accurate books. The CPA can only certify what your records support.
- It carries disclaimers that can puzzle a borrower. The limiting language is normal but can read as weakness.
- It requires consent and review. The §7216 step and the books review take time.
- It won’t guarantee approval. The lender still runs debt-to-income and makes the call.
What to Do Next
- Today: Ask your loan officer whether your loan is a bank-statement program and what default factor and floor apply.
- Today: Request and sign the IRC §7216 consent so the CPA can review your records for this purpose.
- This week: Gather the bank statements and books covering the period the lender will review.
- This week: Have the CPA derive and certify your actual expense ratio with its methodology and disclaimers.
- Before underwriting closes: Confirm the letter is addressed to your lender and keeps the scope-and-limits language.
- If your CPA can’t take it on: Use a specialist CPA letter service to review your books and issue the certified ratio.
If your books are messy or your business changed mid-year, get the scoping right rather than guess at a ratio. Tax Shark’s CPA letter service reviews your records, certifies a defensible expense ratio, and writes it with the disclaimers lenders expect. This article is educational and not a substitute for advice from your own licensed professional.
Frequently Asked Questions
What disclaimers does a CPA put in an expense factor letter? That the figures come from your records and weren’t audited, that it covers a stated period, that it reports the expense ratio only, that it’s not an attestation, that it’s for the named lender alone, and that past results don’t guarantee future expenses.
Why does the letter need so many disclaimers? Because the lender relies on it. Each disclaimer limits a specific duty the CPA never agreed to — auditing your books, verifying income, or owing a duty to other parties — which is what lets them sign the number at all.
What is an expense factor on a bank-statement loan? The percentage of deposits assumed to be business expenses. It’s commonly 50% by default. The lender subtracts it from your deposits before treating the rest as qualifying income.
Can a CPA letter lower the expense factor? Yes. A CPA can certify your business’s actual ratio, and many bank-statement programs will use that figure instead of the default 50% — raising your qualifying income if your real expenses are lower.
Does the letter verify my income? No. It reports an expense ratio, not a dollar amount. The lender applies the ratio to your deposits and computes income itself; the CPA disclaims certifying the income figure.
How much can a lower ratio raise my income? Potentially thousands a month. If deposits average $30,000 and the ratio drops from 50% to 35%, qualifying income rises from $15,000 to $19,500 — a real, loan-changing difference.
How much does an expense factor letter cost? Often a few hundred dollars. Pricing varies with the CPA and the complexity of your books, but for borrowers whose real expenses are well below 50%, the letter usually pays for itself in borrowing power.
Can the CPA state any ratio I ask for? No. The CPA certifies the actual ratio your records support. Asking them to understate expenses to hit a lender’s floor is asking them to misrepresent, and they won’t.
Does this letter work on a conventional mortgage? No. Conventional and agency loans use tax returns or transcripts, not an expense factor. The letter applies to bank-statement (non-QM) programs.
Do I need to sign a consent form? Yes. Under IRC §7216, your CPA needs written authorization before disclosing information drawn from your tax records to your lender.
Who can write an expense factor letter? A licensed CPA — and on many programs an enrolled agent or qualifying tax preparer — who has reviewed your books. If yours can’t, a specialist service can review your records and certify the ratio.
Does the letter guarantee I’ll be approved? No. It supplies a ratio the lender uses to compute income. Approval still depends on the lender’s debt-to-income limits and full underwriting.
Related reading
- CPA Letter Services: Income Verification for Mortgage + FAQs
- What Are the Alternatives to a CPA Letter for a Bank Statement Loan? (w/Examples) + FAQs
- Can Bank Statements Replace a CPA Letter for a Loan? (w/Examples) + FAQs
- Does a Bank Statement Loan Require a CPA Letter? (w/Examples) + FAQs
- How Does a CPA Expense Ratio Letter Raise Your Loan Amount? (w/Examples) + FAQs
- What Documents Do I Need for an Expense Ratio CPA Letter? (w/Examples) + FAQs
- What Are the Qualifications to Refinance a Home? (w/Examples) + FAQs