How to Decide Between 12 and 24 Bank Statements

The Quick Read: The window you use decides which months get averaged into your qualifying income. Rising income usually favors the shorter window. Flat, seasonal, or falling income usually favors the longer one, when the program offers it. The lender’s program often makes the choice for you.

• Qualifying income is your screened deposits, less any expense factor, divided by the number of months in the window.
• Most programs Lendmire places files with run on 12 months of statements, and a smaller group of lenders will also use 24.
• A rising trend rewards 12 months, because older and leaner months drop out of the average.
• One dead month or one huge deposit moves a 12-month average about twice as much as a 24-month average.
• A pure rental-property DSCR file usually skips this question, because it is reviewed on the property’s income instead.

What Does Each Window Actually Mean?

A 12-month window averages your most recent twelve consecutive monthly statements. A 24-month window averages the most recent twenty-four. Nothing else about the math changes.

Here is how the calculation runs on a bank statement file:

1. The lender collects complete, consecutive statements for the accounts you use to show income.

2. The underwriter screens the deposits. Transfers between your own accounts, loan proceeds, gifts, refunds, and one-off unexplained deposits typically come out.

3. On business accounts, an expense factor is applied to the remaining deposits. Personal-account deposits are generally averaged directly.

4. The adjusted total is divided by 12 or by 24. That quotient is your qualifying monthly income.

5. The income then feeds your debt-to-income ratio, which is your monthly debts divided by your monthly income. Credit, reserves, and the property get underwritten alongside it.

HousingWire’s non-QM guide describes bank statement programs the same way: 12 to 24 months of personal or business statements, with an expense factor that may apply. Scotsman Guide adds that this style of underwriting is mostly manual. A person reads your deposits, so the story your statements tell matters.

Who Gets to Choose the Window?

Usually the program does. Across Lendmire’s wholesale network, most bank statement programs are built around 12 months of statements. A smaller group of lenders will use 24 months, and a few let the file run on whichever window produces the stronger result. Each lender’s program sheet sets the rule, and every file is underwritten individually.

That means the real first question is not which window you prefer. It is which programs offer the window you need. A broker who sees many lenders’ guidelines can match your deposit pattern to a program that fits. A single lender can only show you its own menu.

Length of self-employment history also limits the choice. If you have been self-employed for a shorter stretch, the longer window may simply not exist for you. Scotsman Guide notes that asset-based qualification exists for borrowers without enough history or statements. Qualifying from liquid assets is a separate path from averaging deposits.

The Income-Trend Rule

Your income trend decides which window helps. Think of it as asking which months you want in the average.

This is the general rule, and it holds in most files. The edge cases come later here.

A Worked Example With Index Numbers

Here is a modeled example, not market data. It uses index numbers instead of dollars so you can copy the method onto your own statements.

Say you run a small business whose screened deposits grew over two years. The older twelve months average an index of 90 per month.

• The 12-month average is 110.
• The 24-month average is (90 + 110) ÷ 2, which is 100.

The shorter window produces qualifying income 10% higher. Assume the same expense factor applies to both windows, and that 10% carries straight through. At the same debt-to-income limit, 10% more income supports roughly 10% more in monthly obligations. That can mean a larger loan or more room in the ratio.

Now reverse the story. Say the older twelve months average 110 and the recent twelve average 90. The 12-month figure is 90 and the 24-month figure is 100. The longer window wins by about 11% over the shorter one.

Now compare your own two numbers. If the gap is small, the window barely matters and other file factors deserve your attention. If the gap is large, the window is worth real effort to get right.

Five Scenarios in Plain Terms

Rising income. A contractor’s deposits have climbed each quarter. The 12-month window captures the new level and leaves the thin early months out. Choose 12.

Steady income. A dentist with a stable practice sees nearly identical averages either way. The window barely matters. Choose whichever the best program on the file offers, and weigh the paperwork instead.

Seasonal income. A landscaper earns most deposits in warm months. Either window includes a full seasonal cycle, but a 24-month average smooths two cycles instead of one. If the trend is also rising, both rules apply at once. In that case, compute both averages and let the numbers decide.

Declining or recently dipped income. A consultant lost a big client five months ago. The 12-month average carries that weak stretch. The 24-month average dilutes it with stronger earlier months. A lender may still ask for a letter explaining the change, and the longer window is not guaranteed to be available.

One outlier month. A single large deposit or a single dead month changes the 12-month average by about one-twelfth of a normal month. It changes the 24-month average by about one-twenty-fourth. A big deposit that is screened out never matters. A big deposit the underwriter accepts helps more in the shorter window. A dead month hurts more in the shorter window.

Beyond the Average: What Else Changes

The window affects more than one number. Before you chase a higher average, look at these.

Paperwork exposure. Twice the statements means twice the deposits for an underwriter to review. More months can mean more large transfers to explain and more expense scrutiny.

Deposit screening. What counts as an eligible deposit can move your income more than 12 versus 24 months. Moving money between your own accounts, mixing personal and business flows, and unexplained cash deposits all create friction.

Personal versus business statements. Personal deposits generally avoid an expense factor, while business deposits get one. The size of the factor is lender-specific, and no universal formula exists. The gap between personal and business results can be larger than the gap between 12 and 24 months. Business-account income is also typically prorated by your ownership percentage.

Program fit. Pricing, eligibility, and leverage differ from program to program. The window that gives the highest average is not always on the program with the best overall terms.

When This Decision Does Not Apply

Pure DSCR files. A DSCR loan, short for debt service coverage ratio, qualifies primarily on property-level rental income covering the payment, subject to lender guidelines. Scotsman Guide draws the same line: DSCR programs look at property cash flow, while bank statement and 1099 programs average deposits. Statements still matter on a DSCR file, but mainly to show assets and reserves. Lendmire’s complete DSCR loans guide covers that path.

The 12-versus-24 decision applies when you qualify on your own income instead. Common examples include a self-employed investor buying an owner-occupied home or refinancing a primary residence.

Occupancy decides the paperwork regime. A bank statement loan on an owner-occupied home is a consumer mortgage, so consumer disclosure rules such as TRID apply. A bank statement loan on a non-owner-occupied rental, including a short-term rental, is a business-purpose loan and is exempt from TRID. Business-purpose investor loans are reviewed differently from a standard owner-occupied mortgage.

Alternatives to the whole decision. Profit-and-loss programs, 1099 programs, asset depletion, and DSCR all exist as other documentation paths. HousingWire describes non-QM as a toolbox of documentation paths rather than a single loan.

Why No Federal Rule Picks the Window

The government does not pick 12 or 24. The CFPB’s Ability-to-Repay and Qualified Mortgage compliance guide requires a lender to consider eight underwriting factors on consumer-purpose loans, including income or assets, and to verify what it relies on. An earlier edition of the same guide says the rule does not dictate particular underwriting models and calls for reasonably reliable third-party records.

Bank statements are those records. Each program sets its own lookback window, which is why borrowers often cannot simply choose.

Program Parameters to Keep in View

These are typical ranges from select lenders in Lendmire’s wholesale network. They are subject to lender guidelines and are not a commitment to lend.

• Primary residence purchase or rate-and-term refinance: up to 90% LTV through select lenders, with stronger files earning the top of the range.
• Owner-occupied cash-out (primary residence or second home): up to 80% LTV, with loan size and credit playing a role. The 90% purchase figure does not apply.
• Investment-property cash-out: tops out around 75% LTV.
• Investment-property purchase on bank statement documentation: varies by lender.
• Loan amounts: roughly $125,000 to $3,500,000.
• Reserves: commonly around 6 months of the housing payment.
• Asset-depletion alternative: up to about 80% LTV on a primary residence.

Term length follows each lender’s program sheet, so ask rather than assume. Bank statement loans on owner-occupied homes are available where Lendmire’s consumer mortgage licensing applies, which covers 16 states.

A Step-by-Step Way to Decide

1. Count your self-employment history. Under the history a program requires, the longer window is off the table.

2. Pull 24 months of statements. Export every page of every account you would use.

3. Mark ineligible deposits. Strike transfers between your accounts, loan proceeds, gifts, and refunds.

4. Compute both averages. Divide the screened total by 12, using the latest months. Then divide by 24.

5. Find the gap. If the two figures sit close together, pick the program with the best overall terms. If one is clearly higher, find a program that offers it.

6. Check the trend. If income is rising and one weak recent month is distorting the picture, consider waiting until a few stronger months replace it.

7. Ask your broker to run both. Let the numbers on the file, not a general rule, make the final call.

Mistakes to Avoid

• Assuming 24 months is always safer. It adds paperwork and can lower income when your earnings have been rising.
• Ignoring the expense factor. The factor on business statements can matter more than the window.
• Mixing personal and business flows. Keep them separate where you can, because commingled accounts invite questions under either window.
• Moving large sums without a paper trail. Unexplained large deposits get questioned in 12 months and again in 24.
• Treating bank statement loans as unverified. They are fully verified. The statements are the evidence.
• Comparing windows on the wrong accounts. Compare personal to personal and business to business.

HousingWire also makes a related point: non-QM does not mean careless, unverified, or old-style subprime lending. Underwriters review the file, and good deposit habits help under either window.

For most investors, this comes down to timing and fit. Lendmire’s piece 12 vs 24 Months of Statements: Which Bank Statement HELOC Fits? covers the same trade-off for home equity. If you are already in a program and filing a new return changes the picture, read how to switch from 12 to 24 bank statements after filing a new return.

What to Ask Your Loan Officer

• Which programs on my file offer 12 months, 24 months, or both?
• Can you run both averages and show me the gap?
• Which of my deposits will be screened out?
• What expense factor applies to my business account, and can an accountant-prepared ratio change it?
• How is my ownership share treated?
• Which program fits my property and occupancy best?

Many self-employed investors report heavy deductions on their returns. 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.

Key Terms Defined

Lookback window: the number of months of statements a lender averages to calculate your income, usually 12 or 24.

Qualifying income: the monthly income figure a lender uses for your debt-to-income ratio, after deposits are screened and any expense factor is applied.

Expense factor: a percentage of business deposits treated as business costs rather than income. It varies by lender, and no federal formula sets it.

Debt-to-income ratio: your total monthly debts divided by your qualifying monthly income.

Non-QM: a mortgage that does not fit standard agency guidelines and instead uses alternative documentation, such as bank statements.

Asset depletion: qualifying from liquid assets rather than from income deposits.

Bank statement loan: a mortgage that is reviewed on documented income under the applicable program, subject to lender guidelines, using deposits from personal or business accounts.

Next Step

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. You can reach the team at 828-256-2183.

About Lendmire

Lendmire is a non-QM mortgage brokerage (NMLS# 2371349) arranging DSCR investor loans in 41 markets, including Washington, D.C., through wholesale and investor-lending channels. DSCR loans are evaluated by the lender on rental income rather than personal income, subject to lender guidelines — a fit for LLC-owned portfolios, self-employed investors, and operators scaling beyond conventional loan caps. Recognized as a Scotsman Guide Top Mortgage Workplace in 2025 and 2026.

References

1. HousingWire non-QM loans guide

2. Scotsman Guide: Helping borrowers fit the boxes by getting hands-on with non-QM

3. Scotsman Guide: Which groups are driving non-QM lending?

4. CFPB ATR/QM Small Entity Compliance Guide (2021 edition)

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