How a Lender Counts a Seasonal Income Dip on a Bank Statement Mortgage

The Quick Read: A lender counts a seasonal dip by averaging your eligible deposits across the whole review window, so slow months lower the average without automatically disqualifying you, as long as the file shows the pattern repeats each year, the dip is documented, and the overall trend is flat or rising rather than declining. Nothing gets dropped and nothing gets singled out. The slow months simply sit inside the average.

• Most programs in the wholesale network Lendmire works with use 12 months of statements, business or personal.
• Transfers, loan proceeds, refunds and one-time credits come out before the averaging starts.
• Business accounts usually take an expense factor. Personal accounts usually do not.
• Underwriters read direction as well as the average, so a seasonal wave is fine and a steady slide is not.
• Applying right after your slow season is the classic way to get misread.

Picture a landscaper, a short-term-rental operator or a real estate agent. Deposits swell for five months and shrink for four. The bank statement looks lumpy, and the borrower assumes the lumpy months are the problem. They usually aren’t. The way the lender frames them is.

Key Terms Defined

Qualifying income: the single monthly figure a lender settles on after screening and averaging your deposits.

Review window: the run of consecutive months of statements the lender averages.

Expense factor: the share of business-account deposits the lender treats as operating costs rather than income.

Deposit screening: the step where non-income credits, such as transfers between your own accounts, are removed.

Trend review: the underwriter’s check on whether recent months point up, flat or down.

Letter of explanation (LOE): a short written note, backed by documents, that explains an unusual month or pattern.

Debt-to-income (DTI): your monthly debts divided by your qualifying income. It is the test that qualifying income feeds on an owner-occupied file.

How Does the Lender Turn Deposits Into One Number?

The lender totals the deposits in the window, strips out anything that isn’t income, applies any expense factor, and divides by the number of months. There is no separate dip adjustment. The slow months just pull the average down.

Here is the sequence, step by step.

1. Set the window. The program decides it. Scotsman Guide describes self-employed borrowers supplying 12 to 24 months of personal or business statements. Across the lenders Lendmire places files with, 12 months is the common documentation standard.

2. Total every deposit in the window.

3. Screen out non-income credits. Docsumo lists transfers from your other accounts, cash advances, loan proceeds, refunds and one-time items such as an asset sale. A large or unusual deposit must be sourced or it comes out too. Counting a transfer as income is the classic error, because the same dollar gets counted twice.

4. Apply the expense factor to business accounts. Scotsman Guide uses 50% as its example, or a figure from a profit-and-loss statement prepared by a third-party tax professional. Treat 50% as an illustration. Lenders set their own factors, and no one can promise you a specific one.

5. Average. Divide by the months in the window.

6. Feed the result into the file. On an owner-occupied loan, the monthly figure goes into the DTI test next to credit, assets and reserves.

The slow months never get a special penalty or a special pass. They are inside the denominator, and that is the whole mechanism.

A Worked Example With Made-Up Index Numbers

Run the numbers on a seasonal borrower using a simple index instead of dollars. These figures are illustrative only. They are not market data. Each month’s screened deposits are expressed as points.

The twelve months total 1,200 points. Divide by 12 and the average is 100. The qualifying figure is 100 points a month. It does not matter that three months sat at 70 or below. It also does not matter that June and July hit 140.

Now add a business account with an expense factor. If a program applied a 50% factor, the 100-point average would count as 50 points of income, adjusted for your ownership share. If a tax professional’s statement supported a lower factor, more of the average would count. This one lever can move the result more than the dip ever does.

(A dip hurts far less than a thin expense package. Most borrowers worry about the wrong thing.)

Same Dip, Different Window

The window changes which months get averaged, and that changes the answer. A longer window steadies lumpy income. A shorter one favors a borrower who is climbing.

Keep the same seasonal shape and vary the history.

In the second row, the longer window dilutes your best year. In the third, it flatters a year that was weaker. That is why a seasonal borrower with rising income often does better on a shorter window. Lendmire’s piece How to Use This Year’s Higher Income on a Bank Statement Mortgage goes deeper on that tradeoff.

Most programs set one window. Choice exists only where a lender offers it, and the income trend usually decides which window helps you.

Seasonal Dip or Decline? The Misread That Costs Borrowers

An underwriter reads a seasonal dip as normal when the same dip shows up in prior years. The same shape reads as a decline when it doesn’t. The two look identical on a single statement.

Say you apply at the end of February. Your last three months (December, January, February) sit at 60, 70 and 70 on the index above. That is about two-thirds of your 100-point average. Read alone, those three months look like a business shrinking. Read against last year’s December through February, they look like a Tuesday.

A single lost client is the grey zone. A pattern that is part seasonal and part downturn gets read on its worst part. If your trailing months are below last year’s same months, expect questions even if the average clears.

What Goes in the Explanation Letter

A good letter is short, factual and attached to proof. Lenders handle the pattern much better when the borrower names it first.

• The business and its cycle: what you do and why the work clusters in certain months.
• The months in question: list the low months by name and the typical months that follow.
• The comparison: the same months in the prior year, with statements attached.
• Any one-off causes: a lost contract, a storm, a closed location, and what replaced it.
• Supporting documents: a profit-and-loss statement, a tax professional’s letter, or signed contracts for the coming season.

Skip adjectives. Underwriters don’t score enthusiasm. Tax treatment varies; consult a qualified professional.

Personal vs. Business Accounts Through the Slow Season

Business accounts absorb the expense factor, and personal accounts usually don’t. That changes how a dip behaves.

On a business account, a slow month shrinks deposits and the expense factor shrinks what’s left. Pass-through money, such as subcontractor payments that flow in and straight back out, may be excluded or hit with a higher factor. On a personal account, the dip shows up at nearly full weight after transfers are removed, but the figure usually isn’t cut by a factor.

Slow months also attract noise. Refunds, transfers between your own accounts and one-off credits tend to cluster when business is thin. Screening removes them before averaging, so a slow month can look even slower once the clutter is out. Run your own screen first so there are no surprises.

Where the Rule Breaks

The averaging logic is steady, but a few situations bend it.

Short history. A newer business has less than a full cycle to average. Lenders commonly lean more on credit and liquid assets in those files. How much history a program wants is a lender overlay, not a universal rule.

Missing proof. If you claim a lower expense ratio without a profit-and-loss statement or tax professional’s letter, expect the file to fall back to the default factor.

Partly seasonal, partly declining. Covered above. The weaker half drives the read.

A thin compensating profile. Credit strength, assets and reserves can support a file with uneven deposits. That is a lender-specific overlay and not a promise. Across the network, the strictest programs want clean deposits and strong reserves before they bend.

Spouse income in the mix. If a W-2 spouse is on the loan, the math changes. Lendmire’s piece How a Bank Statement Lender Counts Income With a W-2 Spouse covers that case.

Is a Seasonal Dip Even Allowed?

Yes. The CFPB’s compliance guide to its ability-to-repay rule says seasonal income can be considered when it is verified with reasonably reliable third-party records. Its own example is a Christmas-tree farmer who shows $50,000 a year, earned each December. The lender divides it evenly across 12 months. That is a conventional-era example and not a bank statement formula. It still shows the regulator’s logic: smooth the pattern into a monthly figure.

Bank statement loans still require a lender to confirm you can repay. These lenders have more flexibility in how they qualify you, not less responsibility. A bank statement loan is reviewed on documented income under the applicable program, subject to lender guidelines. It is not a shortcut around underwriting.

Which Loan Fits Your Property?

Occupancy often decides the product before the dip ever gets a vote. An owner-occupied purchase or refinance is a consumer mortgage, and the standard consumer disclosure rules, TRID, apply. A bank statement loan on a non-owner-occupied rental, including a short-term rental, is business-purpose and exempt from TRID. Know which one your property is before you compare options.

On an owner-occupied file, typical network ranges, subject to lender guidelines, look like this:

• Primary residence purchase or rate-and-term refinance: up to 90% LTV through select lenders. The strongest files earn the top of the range.
• Primary residence cash-out: up to 80% LTV with a fixed expense ratio, or 75% with an accountant-prepared ratio.
• Second home cash-out: up to 75% LTV, depending on loan size and credit.
• Loan sizes run roughly $125,000 to $3,500,000, with reserves commonly around six months of the housing payment.

On a rental, cash-out on bank statement documentation tops out around 75% LTV. Investment purchase leverage varies by lender.

Here is the practical catch for a seasonal investor. On a DTI-based file, every financed door adds to your debts while your deposits are at their lowest. On a pure rental, a DSCR loan tests the property’s rent against its own obligation instead of your deposits. Qualification there runs primarily on property-level rental income covering the payment, subject to lender guidelines, so your personal slow season stays off the file. Some select lenders in the network will also review coverage below 1.00, though leverage and terms adjust. The complete DSCR loans guide walks through when that route beats bank statements.

An honest toss-up: if you own the home and plan to live in it, bank statements and your seasonal pattern are the story. If it is a rental, the property’s income usually is.

Prep Checklist Before You Apply

1. Pull 12 months of statements, and 24 if the prior year was stronger. 2. Screen out transfers, refunds and one-time credits yourself. 3. Lay each low month next to the same month last year. 4. Ask a tax professional whether a supported expense factor applies to your business account. 5. Draft the explanation letter before the underwriter asks for it. 6. Apply after a stronger stretch if timing is flexible. If it isn’t, apply with the overlay already in the file.

If you are self-employed and want to see how the numbers work, Lendmire can help you compare bank statement loan options based on your deposits, the property, credit profile, leverage, and your goals. Consumer mortgage licensing for owner-occupied files covers 16 states, and nothing here is a commitment to lend.

About Lendmire

Lendmire — NMLS# 2371349 — is a mortgage broker that arranges bank statement, P&L-only, 1099-only and asset-based home financing in 16 states through wholesale lenders, on primary residences, second homes and investment properties. Every option is subject to the lender’s guidelines and full underwriting. Scotsman Guide named Lendmire a Top Mortgage Workplace in both 2025 and 2026.

References

1. Scotsman Guide, “Rev Up the Engine for Non-QM Lending”

2. Docsumo, bank statement income verification

3. CFPB ATR/QM Small Entity Compliance Guide (2014 edition)