Expense Factor Vs CPA Letter On A Platform — The Quick Read: The expense factor is the lender’s default haircut on gross deposits — a flat percentage assumed to cover business costs. A CPA letter replaces that flat guess with your accountant’s certified number. On a platform-deposit file — Airbnb, Vrbo, or another short-term rental booking service — the choice decides how much of your gross deposits actually count as qualifying income. Neither path is automatically better. It depends on your real operating costs, how fast you need the letter, and what your file can absorb.
Key Terms Defined
Expense factor is the percentage a lender subtracts from gross deposits before counting the rest as income, meant to estimate business costs without seeing a full ledger.
CPA letter (sometimes called an expense-ratio letter) is a signed statement from a CPA, enrolled agent, or qualifying tax preparer certifying your actual expense ratio as a percentage of gross revenue.
Platform deposits are the payouts a booking service — Airbnb, Vrbo, Booking.com — sends to your bank account after guests pay and the platform takes its cut.
Qualifying income is the number a lender actually uses to size your loan, after deposits are totaled, averaged, and adjusted by whichever expense method applies.
Non-QM describes any mortgage that doesn’t meet the boxes required for a Qualified Mortgage — including loans that use bank deposits instead of traditional personal-income documentation to prove income.
Here’s how the two paths compare structurally. Neither column reflects pricing — pricing lives in a loan quote, not in this table.
| Factor | Expense Factor | CPA Letter |
|---|---|---|
| Review basis | Flat percentage haircut on gross deposits | Accountant-certified actual expense ratio |
| Documentation | Bank statements only | Bank statements plus a dated, signed letter |
| Best fit | Product businesses, staffed operations, thin margins on paper | Asset-light service businesses, low true overhead |
| Prep effort | None beyond gathering statements | Requires coordinating with a CPA or tax preparer |
| Property types | Primary, second home, or investment — same either way | Same either way |
| Entity vesting | Doesn’t change based on method chosen | Doesn’t change based on method chosen |
| Reserve expectations | Same reserve tiers apply regardless of income method | Same reserve tiers apply regardless of income method |
Across the wholesale network Lendmire places files through, lenders generally calculate business-statement income using a fixed ratio tied to the type of business. This ratio is lower for a service business with no employees. It’s moderately higher for a business with a small staff. And it’s higher still for larger staffed operations or any business selling a physical product. An accountant-provided ratio can replace that fixed figure on most files. A profit-and-loss method, subject to a program cap, exists as a third path for borrowers whose bookkeeping supports it. None of these are universal. They reflect select wholesale-program guidelines, and every file is still underwritten individually.
When the Expense Factor Is the Better Fit
The default expense factor wins when your real costs are close to — or above — what the flat percentage already assumes. If you run a short-term rental with a property manager, cleaning crew, and furnishing budget eating into gross bookings, a CPA letter probably won’t move the needle much. Chasing one wastes time and, per trade press, typically costs $200 to $500 depending on the accountant — money spent for a certified number that lands close to the default anyway.
It also wins when speed of paperwork matters more than a few points of qualifying income. No coordination with a third party, no waiting on a signature, no risk that the letter gets rejected for missing a required detail. On the platform-deposit side specifically, most programs in Lendmire’s network will accept a statement from the booking platform or property manager, or twelve months of your own bank statements showing the deposits — whichever the file already has on hand.
Businesses with staff, inventory, or real overhead almost always fall into this camp. Think of a property-management company with W-2 employees, a short-term rental portfolio run through a management firm, or a retail-adjacent side business. These rarely beat the standard factor with a certified letter. Their actual costs are usually close to, or above, what the default already assumes.
When a CPA Letter Is the Better Fit
A CPA letter earns its cost when your real operating expenses run meaningfully below the default assumption. This happens most often with solo, asset-light businesses. The classic candidate is a consultant, a freelance professional, or a single-member LLC that manages its own short-term rental with no staff and minimal recurring cost. Say the default factor assumes half your gross deposits vanish into overhead, but your actual costs are a fraction of that. In that case, the letter can move qualifying income by a meaningful amount. It does this without touching leverage, credit, or the property itself. The CFPB’s Ability-to-Repay rule generally calls for lenders, QM or not, to make a reasonable, good-faith determination that the borrower can repay. How that determination gets documented can vary. The letter simply offers a different documentation path to get there.
Trade press describes required content fairly specifically. The letter needs the preparer’s full name, professional title, license or credential number, and firm details. It also needs a certified expense ratio stated as a specific percentage, plus confirmation that returns have been filed or prepared for the business. It generally needs to be dated recently enough to satisfy the lender’s timing window relative to the application. It should also cover the same period as the statements being underwritten, though the exact window varies by file and lender. Miss any of those pieces and the letter can be rejected outright. That sends the file right back to the default factor anyway.
Across the wholesale network Lendmire works with, transfers from your own business into a personal account count at 100% of the deposit, no expense factor applied — because the money already passed through the business haircut once. That detail matters for a self-employed borrower who moves platform income into a personal account before it hits the mortgage file; it can shrink or eliminate the reason to chase a CPA letter in the first place. It’s worth checking which account the deposits actually landed in before deciding a certified letter is even necessary.
One market figure worth knowing before you request a letter: trade press reports some programs won’t certify a ratio below 10% — meaning even a very lean business likely won’t get credited with zero cost of doing business. That’s a market-wide figure, not a specific network guideline, and it’s a useful gut check before spending money on a letter chasing an unrealistic number.
How Platform Deposits Change the Math
Platform income runs through the same expense-factor logic as any business deposit — the difference is what counts as an eligible deposit in the first place. Gross bookings aren’t the coverage figure. A platform payout already has the booking service’s own fees stripped out, but it hasn’t had your cleaning, management, furnishing, or utility costs subtracted — that’s what the expense factor or CPA letter is there to estimate.
Eligible deposits generally exclude transfers, refunds, and peer-to-peer payments. These show up in an account but aren’t actual rental revenue. For a purchase transaction, some programs will accept market-rate projections from a platform data source. This means they don’t require twelve months of live history. A refinance, though, almost always wants actual bank statements — usually the most recent two to three months. These need to show the deposits landed and match the reported income. Vacant months typically count as zero in the average, rather than getting excluded. This is worth budgeting for on a seasonal property.
Some lenders use an example where an 80% factor applies directly to gross platform rent. This is done before dividing by the monthly housing payment on a property-cash-flow loan. It’s a different mechanic from the bank-statement business-expense factor described above. It’s tied to a rental-property qualification path, not a personal or business income file. Does your platform income come through a rental property purchased on its own cash flow, rather than your personal or business bank statements? If so, that’s a different product entirely. Lendmire’s complete DSCR loans guide covers how a property’s rent, rather than your deposits, can qualify a purchase or refinance on its own.
A related wrinkle: reporting thresholds for platform-issued tax forms don’t determine whether your deposits count. Under current federal rules, third-party platforms only issue a Form 1099-K once a payee crosses $20,000 and 200 transactions in a year. A host under that threshold may have no 1099-K at all — that doesn’t mean the income disappears from underwriting. Lenders look at the deposits themselves, not the tax form.
Bank Statement vs. Property-Income Qualification
DSCR loans work differently — the property’s own rent, not your personal or business deposits, decides whether the loan is reviewed. A bank statement file looks at what you’ve been depositing; a DSCR file looks at what the property is expected to collect. For an investor whose personal bank statements are messy but whose rental property cash flows cleanly, that distinction can decide which product actually fits. Lendmire’s guide on DSCR loans and expense factor treatment walks through the same expense-factor-versus-CPA-letter decision on a standard bank statement file, without the platform-deposit layer added in.
DSCR loans are designed for non-owner-occupied investment properties. Because they’re business-purpose investor loans, they’re reviewed differently from a standard owner-occupied mortgage.
A Practical Way to Decide
Run a rough gut check before spending money on a letter. If your actual monthly costs — cleaning, management fees, platform commissions already netted out, furnishings, utilities — land close to or above the standard factor tied to your business type, skip the letter. If your real costs are clearly and provably lower, get a quote from your CPA before committing, since the letter costs money regardless of outcome.
Across the wholesale network Lendmire brokers through, files sized from $300,000 up to roughly $6,000,000 run on a portfolio non-QM program. This program uses 12 or 24 consecutive months of statements. A separate bank-portfolio program carries twelve-month-statement files as high as $30,000,000 on its own leverage ladder. Everything above $4,000,000 gets reviewed case by case before submission. Credit floors generally start around 660 on the portfolio side and 680 on the bank-portfolio program. They step up to 700 above the highest loan sizes. Debt-to-income can run as high as 50% on most files. Reserve expectations typically move from three months on smaller loans to nine months on larger ones. These are typical ranges through select wholesale programs, subject to full underwriting. They are not a guarantee for any individual file.
Investors using an LLC to hold a short-term rental should keep the entity’s legal name consistent. This applies across the purchase contract, title, insurance, and any business bank account tied to the expense-factor calculation. A mismatch between the borrowing entity and the account generating the deposits creates a documentation problem. A CPA letter can’t fix that problem on its own. Are you weighing this same decision on a second home rather than a primary residence? The mechanics shift slightly in that case. Lendmire’s breakdown of the expense factor and CPA letter choice on a second home covers how occupancy type changes the leverage available.
Tax treatment can depend on how the funds are used and how the property is held; investors should keep clear records and speak with a qualified tax professional before relying on any deduction.
The Verdict
Neither method is inherently better — the right one depends on your actual cost structure, not on which sounds more sophisticated. A staffed, capital-intensive operation almost always does better under the standard expense factor, because a certified letter is unlikely to beat what the default already assumes. A lean, solo operation with real costs well below the default has a genuine case for paying a CPA a few hundred dollars to certify a lower number, especially on a larger loan where a meaningful income swing matters. When the two paths land close together, the standard factor usually wins on simplicity alone — no third-party coordination, no risk of a rejected letter sending you back to square one.
Frequently Asked Questions
Do I have to get a CPA letter to use a bank statement loan?
No. Most bank statement programs default to the standard expense factor and never require a letter. It’s an optional document borrowers use to try to increase qualifying income, not a mandatory piece of the file.
Does a personal account avoid this decision entirely?
Largely, yes. Personal accounts are generally treated as after-expense income, so most programs count close to 100% of personal deposits without applying a business expense factor at all. The expense-factor-versus-CPA-letter choice mainly applies to business accounts and platform payouts.
What if my short-term rental doesn’t generate a 1099-K?
It can still count as qualifying income. Platforms only issue a 1099-K once a host crosses federal reporting thresholds, but lenders verify income through deposits and platform statements directly — the absence of a tax form doesn’t disqualify the income.
Can I switch from the default factor to a CPA letter mid-application?
Usually, yes, as long as the letter is obtained and dated to match the same statement period already under review. Getting it early avoids delays later in underwriting, since a late or improperly dated letter may not be accepted.
Does the property type change which method applies?
The expense-factor-versus-CPA-letter mechanic works the same whether the property is a primary residence, second home, or investment property — what changes across property types is the leverage available, not the income calculation method.
For current guidelines and terms, see Lendmire’s super jumbo bank statement loan programs page.
Self-employed borrowers can compare both super jumbo programs on Lendmire’s self-employed mortgages page.
About Lendmire
A non-QM mortgage broker (NMLS# 2371349), Lendmire arranges DSCR financing for real estate investors in 40 markets — 39 states plus Washington, D.C. Because deals are underwritten primarily on property cash flow rather than personal income documentation, the structure suits self-employed buyers and entity-owned portfolios. Lendmire places loans through wholesale investor lenders; it is not a direct lender. Scotsman Guide named Lendmire a Top Mortgage Workplace in both 2025 and 2026.
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References
1. mbanc – How to Get a CPA Letter for a Bank Statement Loan
2. CFPB – Ability-to-Repay/Qualified Mortgage Rule
Brandon Miller
Founder & CEO, Mortgage Loan Originator, Lendmire LLC
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Disclosures. The information presented in this article is general market commentary, not financial, legal, or tax advice. Lendmire is a mortgage brokerage (NMLS# 2371349) — not a direct lender or depository institution — and loan placement is subject to lender underwriting. Nothing in this content represents a commitment to lend. Loan terms, pricing, and program availability vary based on borrower qualifications, property characteristics, and state of subject property, and are subject to change at any time. Lendmire complies with Equal Housing Opportunity requirements. Consumer access: nmlsconsumeraccess.org.
