How Tax Reporting Informs Buy-Sell AgreementsMarch 24, 2026

When business partners sit down to draft a buy-sell agreement, most of the conversation centers on the big-picture and big-ticket items, like who gets what, under what circumstances, and how the transition gets funded. What often doesn’t get enough attention is the financial documentation sitting quietly in the background: your tax returns.

Beyond satisfying a filing deadline, your tax returns serve as a record of your business’s financial story. In the context of a buy-sell agreement, that story can make or break the process.

What a Buy-Sell Agreement Actually Needs to Work

A buy-sell agreement governs what happens to an ownership interest when a partner exits, voluntarily or otherwise. Death, disability, divorce, or a falling-out between partners: these events happen more often than business owners like to think about, and without a clear agreement in place, they can unravel even a well-run company.

But the agreement is only as solid as the valuation it’s built on. If the buyout price is too low, the departing owner or their family is shortchanged. Too high, and the remaining partners face a financial burden that could threaten the business itself. Getting the valuation right requires well-documented financials. And that trail starts with your tax returns.

Why Tax Returns Are the First Thing Valuators Look At

When you engage a business valuation professional, whether for planning purposes or in the middle of a dispute, tax returns are typically the first documents they’ll request, often going back three to five years. Here’s why:

They show reported income. Unlike internal financial statements, which can be formatted and adjusted in various ways, tax returns are what the business officially reported to the IRS. They establish a baseline for revenue and profitability that’s difficult to walk back.

They reveal patterns. A single year of financials tells you a snapshot. Three to five years of tax returns tell you a trend: growth, contraction, or volatility. Valuators use these patterns to assess risk and determine appropriate valuation multiples.

They expose add-backs and adjustments. Business owners often run personal expenses through the company or carry non-recurring costs that depress the reported bottom line. A skilled valuator will identify these items and adjust to arrive at a true economic picture of the business. That process is only possible if the underlying tax reporting is thorough and defensible.

They flag inconsistencies. If your internal financials and your tax returns tell materially different stories, you can expect scrutiny, especially in a contested buyout. Gaps between the two create questions that are expensive to answer in a dispute.

The Timing Problem Most Business Owners Miss

Many buy-sell agreements include a valuation formula or trigger a formal appraisal process at the time of a buyout event. What business owners often fail to anticipate is that the quality of that valuation is largely determined by decisions made years earlier, not at the time of the event itself.

If your books have been inconsistent, or if personal and business expenses have been commingled without clear documentation, you’re creating a potential valuation problem. The time to get your financial house in order is not when a buyout is imminent. It’s well before a buyout is on the table.

How Your CPA Fits Into the Picture

A buy-sell agreement is a legal document, and you’ll need an attorney to draft it properly. The financial assumptions within it, including the valuation methodology and the consistency of your reporting, are where your accounting firm can help.

At Curchin, we work with business owners who are thinking ahead about ownership transitions. That means helping them maintain clean, well-organized financials year over year, not just to satisfy the IRS, but to build a documented financial record that holds up when needed.

The work looks different depending on the business. For a professional practice, it might involve clearly separating owner compensation from business distributions so that normalized earnings are easy to calculate. For a family business, it might mean documenting the distinction between family-related expenses and legitimate business costs. None of this is necessarily complicated in isolation, but it requires consistency and an advisor who understands the downstream implications of today’s reporting decisions.

What Happens When the Documentation Isn’t There

In a buy-sell dispute, both sides will often engage their own valuators. When the financial records are clean and consistent, the disagreement usually comes down to methodology, which is manageable. When the records are messy, the dispute expands to include the underlying facts themselves, which is far more costly.

We’ve seen situations where a business that operated profitably for years couldn’t demonstrate that profitability in its financials, because the reporting had never been structured with an outside reader in mind. In a buyout scenario, that ambiguity doesn’t benefit anyone. It creates legal fees, delays, and outcomes that rarely match what either party actually wanted. The straightforward answer is consistent, accurate tax reporting guided by advisors who understand what those documents will eventually be used for.

A Few Questions Worth Asking Right Now

If you have a buy-sell agreement, or you’re in a business where one is appropriate, it’s worth pausing to ask:

Does my current valuation formula still reflect the business’s actual value?
Formulas written years ago may no longer be relevant, particularly if the business has grown or taken on debt.

Are my financials clean enough to withstand scrutiny?
If a valuator pulled your last three years of returns today, would they tell a clear and consistent story?

Does my CPA understand how my reporting decisions affect my business’s valuation?
This is a question more business owners should ask, because the answer isn’t always yes.

A buy-sell agreement is one of the most important planning tools a business owner can have. Its effectiveness depends on the financial foundation beneath it. Tax returns that are accurate and well-documented help protect you and your family when the stakes are highest. Learn more about our valuation and litigation services.