Selling Your Business? Here’s How to Prepare for Due Diligence 

Summary

• A formal business valuation before going to market serves as a dry run for due diligence—surfacing weaknesses, jump-starting document organization, and reducing the pressure on sellers once a letter of intent is signed.
• Every EBITDA add-back must be thoroughly documented with supporting evidence, such as comparable market leases or legal case records, because unsupported adjustments are among the most common points of contention in the due diligence process.
• Sellers who engage advisors 18 to 24 months before a planned transaction arrive with organized financials, a coordinated advisory team, and the confidence to navigate buyer scrutiny without scrambling.

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Due diligence is rarely a pleasant experience for sellers, but with the right preparation, it doesn’t have to be overwhelming. Without it, deals fall apart, valuations get renegotiated, and sellers find themselves scrambling under pressure they didn’t anticipate. The good news is that you don’t have to navigate it alone. With the right team of advisors in your corner and a little advance planning, you can walk into due diligence with confidence—and walk away with a better deal. 

What is the due diligence process when selling a business? 

The due diligence process begins once you have a signed letter of intent (LOI) from the buyer. At this point, the burden shifts to you as the seller: you must substantiate everything outlined in your confidential information memorandum (CIM) and the initial LOI terms, including the agreed-upon purchase price (often expressed as a multiple of your company’s adjusted EBITDA). 

Due diligence gives the buyer an opportunity to examine exactly what they’re acquiring and assess the risk they’re taking on. The standard due diligence period runs 90 to 120 days, though some buyers may push for 60. During this window, you’re still running your business while simultaneously responding to a steady stream of requests, which can feel like a second full-time job. 

Why a business valuation is the first step in due diligence preparation 

One of the smartest things a seller can do before going to market is obtain a formal business valuation. The documentation a valuator requests closely mirrors what a buyer will ask for during due diligence, making it an invaluable dry run in a lower-stakes environment. 

Beyond document preparation, a valuation can surface potential weaknesses in your business, giving you time to address them before a buyer does. It also jump-starts the process of compiling your financial, operational, and legal data into a single central location, often called a data room, so that when a buyer requests your 2023 sales by customer or accounts receivable aging report, you’re not scrambling. 

Because due diligence places a heavy burden on a small number of people, we also recommend predefining who is responsible for each component of the process well in advance. Clarity of ownership reduces delays and prevents critical requests from falling through the cracks. 

How clean financial records impact your business sale 

If your financial reporting is disorganized by the time due diligence begins, it can kill a deal before it gains momentum. Buyers want to see businesses with sound systems and clean, consistent financial records over time, and not books that appear to have been tidied up right before the sale. 

This means having reliable accounting software, a consistent monthly close process, and financial statements that tell a coherent story from year to year. If your internal infrastructure isn’t there yet, the time to address it is well before you go to market. 

How to support and defend your EBITDA add-backs 

By the time you reach due diligence, you’ve already presented your normalized EBITDA figure, and buyers will scrutinize it closely. Every adjustment you’ve made, particularly add-backs, needs to be well-documented and defensible. 

Consider a common scenario: a business owner who leases real estate to their own company. If they’ve historically charged $100,000 per year in rent on a building where the market rate is $50,000, they may claim a $50,000 add-back to EBITDA. To support that adjustment, they’d need to provide documentation of the per-square-foot price being charged, along with comparable market leases in the area that reflect similar rates—ideally, six or more comps. 

Similarly, if a one-time employee lawsuit was settled in the prior year, the associated legal expenses might reasonably be added back as a non-recurring item. But the buyer will want documentation confirming the case is fully closed, evidence that it was genuinely an isolated event, or anything else that supports the durability of future cash flow projections. 

Weak or unsupported add-backs are one of the most common points of contention in due diligence. Getting ahead of them with thorough documentation can protect both your valuation and the deal itself. 

Why your advisory team can make or break your deal 

Due diligence is one of the most demanding periods a seller will face, and attempting to navigate it without experienced advisors is a significant risk. If your business lacks a sound internal financial structure—a qualified accounting team, CFO, or controller—bring in outsourced help as early as possible. It’s common for small businesses to rely on an office manager who has absorbed controller and HR responsibilities over time. While that person may be invaluable to daily operations, they’re rarely equipped to manage the volume and complexity of a due diligence process. An outsourced accounting firm can help you establish the right systems, handle monthly bookkeeping, provide higher-level financial reporting, and support your team throughout the transaction. 

When it comes to responding to buyer requests, having an experienced advisor in the room makes a meaningful difference. Some document requests are straightforward for a transaction advisor or accountant, but confusing and anxiety-inducing for a business owner who has never been through a sale. With your authorization, an advisor can respond to requests directly or serve as a sounding board before anything is submitted. Sending the wrong document, or the right document without appropriate context, can put a deal at risk. An experienced advisor knows when the data needs a narrative explanation and, equally important, when it’s appropriate to push back on a buyer’s request. 

The advisors you engage should also bring a network with them. Your outsourced accounting firm or transaction advisor should already have established relationships with M&A attorneys, wealth managers, and other professionals you’ll need on your team. 

When should you start preparing for due diligence? 

The single most effective thing a seller can do to prepare for due diligence is to start early. The process looks dramatically different for clients who engage advisors 18 to 24 months before a planned sale versus those who come to us two months out. The runway matters—it’s the difference between identifying and fixing a problem and having to explain it away under pressure. 

The value of early preparation isn’t just organizational. It’s the communication and collaboration across your advisory team working together toward a common goal. That coordination is difficult to replicate when you’re already under the gun.  

Due diligence will always require effort. But sellers who prepare thoughtfully, build the right team, and start the process early arrive at the table with something invaluable: confidence. If you have any questions or need assistance, please use the form below to contact us today.