Expense Factor Vs CPA Letter On A Second Home Bank Statement Loan — The Quick Read: A bank statement loan is reviewed for a borrower on deposits, not traditional personal-income documentation, but business deposits get discounted before they count as income. The default discount is a fixed expense factor. A signed CPA letter can replace that fixed number with the business’s actual cost ratio — sometimes raising qualifying income, sometimes lowering it. Neither choice changes credit score, reserves, or leverage; it only changes the income number that feeds the file.
For a high-earning self-employed borrower buying a second home, this decision often moves qualifying income more than any other single input on the file. Get it right and the file clears comfortably. Get it wrong and the borrower leaves purchasing power on the table — or worse, submits a letter that hurts more than it helps.
Key Terms Defined
Expense factor — a fixed percentage subtracted from business bank deposits before the remainder counts as qualifying income, meant to approximate overhead the underwriter can’t otherwise verify.
CPA letter — a signed statement from a CPA, enrolled agent, or qualifying tax preparer that certifies the business’s actual operating expense ratio, replacing the fixed default with a documented number.
Qualifying income — the monthly income figure underwriting actually uses in debt-to-income math, calculated from eligible deposits after the expense factor or CPA-certified ratio is applied.
Second home — an occupancy category that allows personal use of the property while permitting occasional rental income, sitting between a primary residence and a full investment property in how it’s underwritten.
Business-purpose loan — financing tied to a rental property’s own cash flow rather than the borrower’s personal income; second-home bank statement loans are not this — they’re consumer-purpose loans underwritten to the individual.
The Side-by-Side
The expense factor is faster to use and requires no third party. The CPA letter takes more effort and only helps borrowers whose real costs run well below the default assumption.
| Factor | Expense Factor | CPA Letter |
|---|---|---|
| Review basis | Fixed percentage applied to deposits | Actual certified expense ratio |
| Documentation needed | None beyond bank statements | Signed letter from CPA/EA/preparer |
| Best for | Lean-overhead businesses near or above the default | Businesses with genuinely low actual costs |
| Timeline impact | No added step | Adds a document-gathering step before submission |
| Risk | May understate income for low-cost businesses | May overstate income for high-cost businesses if used carelessly |
| Reserve/credit effect | None — separate underwriting factors | None — separate underwriting factors |
Through select lenders in Lendmire’s wholesale network, business bank statements apply one of a few fixed ratios depending on business structure: 20% for a service business with no employees, 40% for a business running one to five employees, and 50% for larger staffed operations or any product-based business. An accountant-provided ratio, or a profit-and-loss method capped at 80% of revenue, can stand in for those fixed tiers on files where it helps.
Key Takeaways
- The expense factor is the lender’s default assumption about overhead — it applies automatically unless replaced.
- A CPA letter only helps when the business’s real cost structure runs lower than the applicable fixed tier.
- Personal-account deposits typically skip the expense factor entirely, since that money has already cleared business costs.
- Second-home occupancy is a separate overlay from the income-documentation choice — it affects leverage and credit floor, not the expense math itself.
- Getting this wrong doesn’t just cost convenience — it can shrink or inflate qualifying income enough to change what property the borrower can even offer on.
When the Expense Factor Is the Better Fit
The fixed factor is the right call when a business’s real costs run close to or above its applicable tier — paying a CPA for a letter in that situation produces nothing and burns time. A restaurant, a contractor, or any product-heavy business with real overhead in the 50%-plus range typically has nothing to gain from certifying its actual ratio, because the certified number would come in at or above the default anyway.
The fixed factor also wins on simplicity. No third party, no signature, no scope-of-work question about who’s qualified to sign. For a borrower whose deposits already comfortably clear the target coverage without any adjustment, spending time on a CPA letter adds a step without moving the outcome.
Experienced brokers watch for a practical break-even point. If the business’s actual costs run higher than the tier it would normally default into, the fixed number is either equal to or better than what a certified letter would produce. In that case, you don’t need a CPA letter — and using one could actually hurt the file, if it certifies a number higher than the default the business would have gotten automatically.
When a CPA Letter Is the Better Fit
The letter earns its keep when the business’s real operating costs run meaningfully below the fixed tier it would otherwise be assigned — think a solo consultant, a professional-services entity, or a business with unusually lean overhead relative to its size class. In those cases, a signed certification can move qualifying income up enough to change the deal.
The letter also matters for borrowers whose business structure doesn’t map cleanly to the fixed tiers — say, a business with a handful of contractors instead of W-2 employees, where the underwriter has discretion on which tier applies by default. A CPA’s certification removes that ambiguity and replaces guesswork with a documented number.
It’s also the right tool when a borrower’s qualifying income is close to the line for the property they want, and the fixed factor is what’s holding them back. A well-prepared letter — signed, on letterhead, with the preparer’s credentials and a stated basis of knowledge — can be the difference between qualifying at the leverage the borrower wants versus stepping down a tier.
One caution worth naming plainly: the letter is supporting documentation, not a substitute for the required bank statements themselves. Underwriting still wants the deposit history; the letter changes how that history is converted into income, not whether it’s required at all.
How the Occupancy Choice Sits on Top of This
Choosing between the expense factor and a CPA letter is entirely separate from how the property itself gets classified — but the two decisions interact. A second home allows personal use while still permitting occasional rental, which is exactly why bank statement underwriting fits it: the loan is reviewed for the person, not the property. That’s a different framework from a business-purpose rental loan, where the property’s own cash flow — not the owner’s deposits — carries the file.
Through select lenders in Lendmire’s wholesale network, second-home leverage on a bank statement file runs roughly five points below what’s available on a primary residence at the same loan size, and typically follows a step-down ladder as the loan amount grows — from around 85% purchase leverage at entry-level pricing down through the mid-70s and 60s as size climbs into the low millions. Above roughly $3,000,000 on a second home, files move to case-by-case review with a higher credit floor, tighter housing-history requirements, and longer seasoning on any credit event — never a flat “up to” number at that size.
Credit generally needs to clear 660 to 680 depending on the program, with reserves running three months on smaller loan amounts, stepping to six and then nine months as the loan size increases. Debt-to-income can run as high as 50% on these files. None of that changes based on whether the file uses the fixed expense factor or a CPA letter — the occupancy overlays and the income-documentation choice are two separate levers on the same application.
Here’s something worth knowing if your plans might change: the IRS uses its own separate test to decide if a property still counts as a residence for tax purposes. A property counts as personally used if the owner uses it for more than 14 days, or more than 10% of the days it’s rented at fair value — whichever number is greater. You can read more at IRS Topic No. 415. This tax classification doesn’t automatically match the loan’s occupancy classification. If you rent your second home more than you originally planned, make sure you understand both the tax side and the loan side on their own.
When rental income from the property itself is what’s actually being used to qualify — rather than the borrower’s own deposits — that’s a different product altogether. That’s the DSCR lane, where underwriting looks at the property’s rent covering its payment rather than the owner’s personal cash flow. Investors weighing whether a purchase belongs on the bank-statement side or the DSCR side can work through the mechanics in Lendmire’s complete DSCR loans guide.
Personal Accounts Change the Math Entirely
Deposits that land in a personal account usually skip the expense factor entirely. That’s because the money has already covered whatever business costs came before it reached you. This is why the choice between using an expense factor or a CPA letter really starts with a question about the business account. If you pay yourself a steady owner’s draw into a personal account, personal statements alone — with no factor applied — may give you a cleaner, higher qualifying-income number than running business statements through either the fixed tier or a certified ratio. On files where both options are available, it’s worth asking whether personal statements alone tell a better story than the business side ever could.
DSCR loans are built for non-owner-occupied investment properties. Lenders review them differently than a standard owner-occupied mortgage, because they’re business-purpose investor loans. That’s why the second-home bank statement path and the DSCR path rarely apply to the same property.
Want to compare the expense-factor approach with a CPA letter side by side? Check out how setting the expense factor on a second home and using a CPA letter to raise income on a second home work as standalone strategies. Each one covers half of this decision in more depth.
The Verdict
Neither option is better in the abstract — the right answer depends entirely on where the business’s real cost structure sits relative to its applicable fixed tier. A lean, low-overhead business almost always does better with a certified letter. A business running real costs at or above its tier gains nothing from one and may lose ground. There’s no universal winner here, and any broker who claims otherwise hasn’t looked at enough files.
What both paths share: neither changes the second-home overlays, the credit floor, or the reserve schedule sitting underneath the file. Those stay fixed regardless of which income-documentation route the borrower takes. The decision is entirely about which number — a fixed assumption or a certified fact — produces the qualifying income the deal actually needs.
The reserve requirements, expense tiers, and leverage figures in this article reflect select wholesale-program guidelines. These can change based on the lender, your credit profile, and the property. None of this is a promise to lend — every file gets underwritten on its own. Tax treatment can also depend on how you use and title the property. Investors should keep clear records and talk to a qualified tax professional before assuming any outcome. Your exact terms will depend on the lender’s guidelines, the property type, your leverage, and a full review of your file.
Frequently Asked Questions
Can a borrower switch from the fixed expense factor to a CPA letter mid-application?
Yes, in most cases — the letter simply replaces the fixed percentage in the same income calculation, so it can be added later if the numbers aren’t working as expected. The tradeoff is added time to gather the signed document and route it through underwriting before a final income figure is locked in.
Does a CPA letter ever hurt an application?
It can, if the certified ratio comes in higher than the fixed tier the business would have gotten by default. This happens most often with high-overhead businesses — restaurants, contractors, and similar operations — where actual costs run well above the standard assumption for that business size.
Does the occupancy classification (second home vs. investment property) change which expense factor applies? No — the expense-factor mechanics are the same regardless of occupancy. What changes with occupancy is the leverage ladder, the credit floor, and the reserve schedule sitting on top of the income calculation, not the income math itself.
Can personal and business statements both be submitted to see which produces better qualifying income? Often yes. Because personal-account deposits typically skip the expense factor entirely, running both sets of statements can surface a materially different qualifying-income number, particularly for borrowers who draw a consistent owner’s salary.
Is a CPA letter required, or is it always optional?
It’s generally optional and used strategically — most programs default to the fixed expense factor unless a certified letter is submitted to replace it. Some underwriters may request one anyway if a business’s structure doesn’t cleanly fit the standard tiers.
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
As a non-QM mortgage broker (NMLS# 2371349), Lendmire facilitates DSCR investor loans across 40 markets, including Washington, D.C. DSCR eligibility is generally reviewed around property-level rental income instead of personal income documentation, subject to lender guidelines, serving LLC-structured portfolios and self-employed borrowers who don’t fit conventional boxes. A two-time Scotsman Guide Top Mortgage Workplace (2025, 2026).
Lendmire’s Top Mortgage Workplace recognition is documented by Scotsman Guide 2025 Top Mortgage Workplace and Scotsman Guide 2026 Top Mortgage Workplace.
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References
1. Fannie Mae Selling Guide — B2-1.1-01, Occupancy Types
2. Internal Revenue Service — Topic No. 415, Renting Residential and Vacation Property
Brandon Miller
Founder & CEO, Mortgage Loan Originator, Lendmire LLC
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Compliance and disclosures. Lendmire (NMLS# 2371349) is a licensed mortgage broker and is not a direct lender, depository institution, financial advisor, or tax professional. Content in this article is general market analysis and educational information — not financial, legal, or tax advice for any specific situation. Lendmire does not guarantee loan approval; every transaction is subject to underwriting by the funding lender. Mortgage pricing and loan program guidelines are subject to change at any time without notice and vary by borrower characteristics, property type, and state regulations. Lendmire complies with Equal Housing Opportunity. Licensure verification: NMLS Consumer Access.
