Is a 12-Month or 24-Month Bank Statement Loan the Better Fit?

The Quick Read: It depends on your deposit trend, and the better window is whichever one produces stronger qualifying income you can document and defend, within what the lender’s program allows. A 12-month window usually fits when income is rising or the business is young, because it captures your recent run-rate. A 24-month window usually fits when income is uneven, seasonal, or recently dipped, because it smooths the swings.

• Rising income favors 12 months; a 24-month average drags the figure down.
• Seasonal or lumpy income favors 24 months, which smooths the peaks and troughs.
• Declining income is a problem under either window, because underwriters read the trend.
• The program sheet decides which windows you can use. Many programs offer only one.
• For a pure rental purchase, a DSCR loan may make the whole question moot.

Most borrowers treat this as a preference. It is closer to arithmetic with a lender’s rulebook on top. The rest of this piece shows how to run that arithmetic yourself, where the exceptions sit, and when the whole bank statement lane is the wrong tool for an investor.

What the Window Actually Changes

The window changes one thing: which months of deposits get averaged. Everything else, including deposit scrubbing, expense factors, reserves, and credit review, works the same way.

A bank statement loan is a non-QM program. Instead of tax-return income, the underwriter converts consecutive personal or business statements into qualifying income. Across the wholesale network Lendmire works with, the process follows the same general path:

1. The borrower supplies every page of every statement for every account used. 2. The underwriter removes transfers between accounts, loan proceeds, refunds, and one-time deposits. 3. Eligible deposits are totaled. 4. On business accounts, a lender-set expense factor backs out overhead. The factor varies by lender and business type, and some programs accept an accountant-prepared expense ratio instead. 5. If the borrower owns less than 100% of the business, income is prorated to the ownership share. 6. The result is divided by the number of months in the window, and that monthly figure feeds debt-to-income, reserves, and credit review.

Change the divisor and the included months, and the same deposits produce a different monthly number. That is the whole decision.

12 Months vs. 24 Months Side by Side

The last row matters more than the first five. A table can tell you which window you would prefer. Only the program sheet tells you which one exists.

Three Scenarios, Same Deposits Run Both Ways

Rising income: 12 months wins. Picture a consultant whose second year of deposits runs well above the first. The 24-month average blends in the weaker year and lands below the recent run-rate. The 12-month figure reflects where the business is now. If the borrower needs the higher number to clear debt-to-income, the shorter window is the stronger play.

Seasonal or lumpy income: 24 months usually wins. Say a contractor has a strong summer and a thin winter, and the trailing 12 happens to end in a slow stretch. A longer window captures a full pair of cycles and shows a more representative figure. If the two averages sit close together, the choice barely matters, and the cleaner set of statements should drive it.

Declining income: neither window rescues you. Here’s the catch. A 12-month window shows the drop sharply. A 24-month window may mask it, but underwriters can truncate to the recent period, which cancels the smoothing benefit. If deposits are falling, the honest answer may be to wait a few months, document the cause, or consider a different structure entirely.

Run It Yourself in Four Steps

Skip the guesswork. Before choosing, do this with your own statements:

1. Pull 24 months of statements, every page, for every account you might use. 2. Total the eligible deposits for the most recent 12 months and for the full 24, after removing transfers, loan proceeds, refunds, and one-off items. 3. Divide each total by its month count and compare the two monthly figures. 4. Look at the direction. If the 12-month number is meaningfully higher, income is rising. If it is lower, recent income has slipped.

If the two figures land close together, ask the lender to evaluate both and let the file choose. If they diverge, the gap tells you which program sheet to ask about first.

Deposit Quality Beats Window Length

A clean 12-month file can outperform a messy 24-month file. Underwriters care less about how many months you submit than about whether each deposit is clearly business income.

Common problems include commingled personal and business accounts, overdrafts, large unexplained deposits, and money moved between your own accounts. Real estate sale proceeds and capital gains do not count as income. Lenders scrub aggressively here because the CFPB’s Ability-to-Repay compliance guide expects a lender to verify the income or assets it relies on for owner-occupied, consumer-purpose loans. That is why bank statement loans are documented loans, not no-doc loans. They qualify on documented income under the applicable program, subject to lender guidelines.

Business statements get an expense factor. Personal statements are read closer to raw deposits, often with evidence that the business is operating. Separate rental deposits from business deposits before you submit anything.

Edge Cases Worth Knowing

A business under two years old. Some programs accept 12 months of statements with a shorter self-employment history, sometimes paired with strong assets. Most programs prefer around two years. It is a program-by-program exception, not a right.

A weak year in the past. If the soft stretch falls outside the 12-month window, the shorter window leaves it out of the average. That is the real advantage of 12 months for a recovering business.

Larger loan sizes. Loan amounts across the network run roughly $125,000 to $3,500,000. At the upper end, underwriters tend to give a longer track record more weight, so a 24-month file can read as the more comfortable one. Treat that as a pattern, not a rule.

Partial ownership. Income is prorated to your share, so a 40% owner is reviewed on 40% of the business’s eligible income.

One window only. The Lendmire network documents income from 12 months of statements as the baseline, and individual lender sheets set the rest. If you want a 24-month calculation, ask before gathering documents. Few programs let you pick the favorable window freely.

How Many Months Do Lenders Actually Look At?

This question trips up borrowers who are comparing loan types. A standard mortgage usually asks for about two months of statements, mainly to confirm assets and down payment. A bank statement loan uses 12 or 24 months because the statements are the income documentation. Same documents, entirely different job.

When the Whole Question Is the Wrong One

For an investor buying a pure rental, the better question may be whether a bank statement loan is the right tool at all. A bank statement loan underwrites the borrower: deposits, expense factor, and personal debt-to-income. A DSCR loan reviews the property’s rental income, qualifying primarily on property-level rental income covering the payment, subject to lender guidelines. For a straight rental purchase, DSCR typically sidesteps deposit analysis and personal DTI entirely, which is why investors with declining deposits often steer that way. Lendmire’s complete DSCR loans guide covers how that math works.

A bank statement loan can still win for an investor in a few situations:

• The property will be your primary residence or second home, where the rental-coverage test does not apply.
• Rent coverage on the property is thin, but your deposits are strong.
• You are using the equity in an owned property, where the cash-out ceilings differ by occupancy.

Many operators split the portfolio: a bank statement loan on the primary residence, DSCR on the rentals.

Leverage by Occupancy

Leverage depends on what the property is, not on which window you choose. Typical ranges from select lenders in Lendmire’s wholesale network, all subject to lender guidelines, credit, and loan size:

Stronger files earn the top of each range. Investment purchase leverage on bank statement documentation varies by lender, so treat it as a case-by-case question. Reserves commonly run around six months of the housing payment.

Why Occupancy Changes the Rulebook

Occupancy also decides which disclosure regime applies. An owner-occupied file, meaning a primary residence or second home, is a consumer mortgage, so TRID disclosures apply. A bank statement loan on a non-owner-occupied rental, including a short-term rental, is often a business-purpose loan and may be exempt from TRID, depending on the loan’s purpose.

The exemption turns on the loan’s purpose, not simply the property type. Under Regulation Z § 1026.3, credit extended primarily for a business or commercial purpose is exempt, and the eCFR text adds that credit to someone other than a natural person, such as an LLC, is also outside the rule, subject to program terms. Not every “investment” property qualifies, and a consumer-purpose loan misclassified as business-purpose carries real risk. A qualified attorney can sort out edge cases. Tax treatment varies; consult a qualified professional.

Key Terms Defined

Lookback window: The number of consecutive months of statements the lender averages to produce qualifying income.

Expense factor: The percentage of business deposits a lender removes to account for overhead, set by the lender based on business type and documentation.

Deposit scrubbing: The underwriter’s removal of transfers, loan proceeds, refunds, and one-time deposits from the total.

Non-QM: A mortgage that does not follow standard qualified-mortgage documentation rules, which is how bank statement programs exist.

Asset depletion: A qualification method that treats liquid assets as a stream of income instead of using deposits.

Common Misconceptions

• “Bank statement loans are no-doc.” Not true. Income is documented and verified.
• “24 months is always safer.” Not when income is rising, because the blend lowers qualifying income.
• “You pick whichever window you like.” The program decides which windows exist.
• “All deposits count.” Transfers, loan proceeds, and one-time items come out.
• “The expense factor is a fixed number.” It is lender-set and varies with business type and supporting documents.

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 programs are available in 16 states, and each file is underwritten individually. Call 828-256-2183 or request a quote.

About Lendmire

Lendmire (NMLS# 2371349) is a mortgage brokerage serving self-employed and high-net-worth borrowers in 16 states. Bank statement, P&L-only, 1099-only and asset-based mortgages are arranged through wholesale lending channels; Lendmire brokers the financing and the lender underwrites each application. Scotsman Guide named Lendmire a Top Mortgage Workplace in both 2025 and 2026.

References

1. CFPB Ability-to-Repay and Qualified Mortgage Rule Compliance Guide

2. CFPB Regulation Z § 1026.3