Tying a company's tax returns to its books
July 28, 2026 · 6 min read · Mike
When you ask a seller for financials, you'll usually get two sets of numbers. One is the tax returns the company filed with the IRS. The other is the company's own financial statements, the profit and loss statement and balance sheet from its bookkeeping software.
They almost never match exactly. That's normal, and most of the differences have ordinary explanations. Your job is to find each one. A small gap with a clear reason is fine. A gap that nobody can explain is one of the most important things you can learn about a company before you buy it.
If you haven't worked through a company's statements before, start with reading a profit and loss statement, then come back.
Why the numbers differ
These are the usual, legitimate reasons:
- Different periods. The books might run through last month, while the latest return covers a year that ended months ago. Compare full years to full years.
- The accountant's year-end changes. Many companies keep their own books during the year, and their outside accountant makes corrections when preparing the return: reclassifying expenses, adjusting inventory, recording depreciation. Often those changes never get entered back into the company's books.
- Cash versus accrual. A company can count income when the customer pays (the cash method) or when it sends the invoice (the accrual method). If the return uses one and the books use the other, a big job invoiced in December and paid in January lands in different years.
- Depreciation. Tax rules often let a company deduct equipment and vehicles faster than its books spread the cost. A year with new trucks can show much lower profit on the return than in the books.
- Expenses the tax rules limit. Some costs on the books, like certain meals and entertainment, aren't fully deductible, so taxable income ends up higher than book profit.
- The owner's pay. On a sole proprietor's return, there's no line for the owner's own pay; whatever the owner took out is still inside the profit. An S corporation usually reports the owner's salary as officers' compensation. The books may record it differently from either.
Know which return you're looking at
How the company is set up decides which return it files, and how much help that return gives you.
| How the company is set up | The return it files | What to know |
|---|---|---|
| Sole proprietor, or a one-member LLC by default | Schedule C, part of the owner's personal Form 1040 | No balance sheet and no built-in reconciliation |
| S corporation | Form 1120-S | Includes a balance sheet and a reconciliation, unless the company is very small |
| Partnership, or an LLC with two or more members by default | Form 1065 | Same, with its own small-company exception |
| C corporation | Form 1120 | Same |
The IRS sets those default treatments for LLCs; an LLC can choose to be taxed as a corporation instead. Ask the seller which way theirs is set up.
Use the reconciliation built into the return
Corporate and partnership returns contain two schedules that do part of your work for you.
Schedule M-1 is titled "Reconciliation of Income (Loss) per Books With Income (Loss) per Return." It starts with the profit on the company's books, lists the items that differ, and ends at the income on the return. If it's filled in, the company's accountant has already listed the main differences for you.
Schedule L is the balance sheet "per books." Compare its year-end figures to the company's own balance sheet for the same date. Cash, loans and equipment should be close. Our post on reading a balance sheet explains what each line means.
Small companies can skip both. On Form 1120-S, for example, an S corporation with total receipts and total assets both under $250,000 doesn't have to complete them. In that case, and for any Schedule C business, you'll build the reconciliation yourself.
How to tie them, step by step
- Line up the same years. Put three years of returns next to the company's full-year profit and loss statements for the same years.
- Start with revenue. Compare gross receipts on the return to total revenue in the books. Revenue is usually the easiest line to match. Write down the difference for each year.
- Then compare profit. Write down book profit, return income and the difference.
- Explain every difference. For each item, find the document behind it: the depreciation schedule, the accountant's year-end adjustments, the inventory count.
- Add it up. When the explained items equal the gap, the numbers tie.
Here's how that might look for a hypothetical HVAC company:
| Item | Amount |
|---|---|
| Profit on the company's books | $210,000 |
| Faster tax depreciation on two new trucks | minus $38,000 |
| Year-end inventory adjustment the accountant made | minus $9,000 |
| Meals and entertainment the tax rules don't fully allow | plus $5,000 |
| Income on the tax return | $168,000 |
Every line has a document behind it, and the total matches the return. That's a gap that closes.
Make sure the returns are the real ones
Copies of returns can be edited, so a lender checks them with the IRS directly. Through the IRS's Income Verification Express Service, a taxpayer can authorize a lender to get transcripts of its returns, for example by signing Form 4506-C.
If you finance with an SBA loan, this check isn't optional. The SBA's lending rules require the lender, on a purchase, to verify the seller's financial information against IRS tax transcripts. Any significant differences have to be resolved to the lender's satisfaction. It's better for you to find a gap first than for the lender to find it a week before closing.
Later, you'll also check reported revenue against the company's bank deposits. Tying the returns to the books comes first, because it tells you which set of numbers you're testing.
When the gap won't close
Sometimes the differences don't add up, and no one can say why. What it means depends on which way the gap runs.
- The books show more revenue or profit than the return. Either the books are wrong or income wasn't reported. Neither is good news. You can't verify the extra, and a lender won't count it.
- The seller says, "We take in more cash than shows." That's the seller telling you the tax returns understate income. Don't pay for earnings that aren't on the returns, and ask your attorney and accountant what it could mean for you, particularly if you'd be buying the company's stock rather than its assets.
- The return shows more than the books. This often points to weak bookkeeping. It's less alarming, but it raises a fair question: which numbers can you trust month to month? Rely on the returns, and plan to improve the books after you buy.
- Missing, late or amended returns. Ask why, and ask to see the IRS correspondence.
In every case, the practical answer is the same: base your price on what you can verify. If a seller wants to be paid for numbers they can't support, that's a reason to slow down, and sometimes to walk away.
What to do this week
- Ask for three years of complete tax returns, with every page and schedule, and the year-end profit and loss statement and balance sheet for the same years.
- Build a one-page comparison: revenue and profit, books against return, year by year.
- Ask for the depreciation schedule and the accountant's year-end adjusting entries.
- Ask the seller's permission to talk with their accountant. A short call often explains in minutes what would take you hours to work out.
- Have your own accountant review your comparison before you make an offer.