Due diligence in a business sale typically runs 60 to 90 days from the signing of a letter of intent to closing in the lower middle market. The IBBA/M&A Source Market Pulse has consistently reported about three to four months from letter of intent (LOI) to close. Longer-than-necessary timelines commonly trace back to four specific bottlenecks.
If you’ve just signed an LOI, or expect to soon, you probably have a closing date in mind and some doubt about whether it will hold. In our experience, that depends more on the seller than on the buyer. A thorough buyer can usually finish in about 90 days when requests come back quickly and complete. When documents arrive in pieces, each answer raises a new question, and the owner keeps getting pulled back into running the business, the same diligence can stretch to five or six months. Each of the four bottlenecks below is a version of that problem, and most are largely within the seller’s control.
Bottleneck One: A Data Room That Raises More Questions Than It Answers
A disorganized data room costs you more than a slow first week. Buyers read it as a sign of how the business is run. If their team opens the financial folder and finds three years of tax returns in different formats, inconsistent file names, and missing supporting schedules, they don’t assume everything else is fine. They assume they need to look harder.
That shows up in the due diligence questionnaire (DDQ). Every gap in the data room becomes another question, and in our experience, the DDQ back-and-forth is where many deals this size lose the most time. At most companies, one or two people end up answering hundreds of questions across finance, legal, HR and operations, on top of their regular jobs. Response times stretch from days to weeks while the buyer’s team waits.
A well-organized data room, by contrast, preempts questions and provides the pertinent information buyers need to support their acquisition. Clean, well-documented financials that reconcile to supporting schedules, customer and supplier lists with concentration or significant changes already flagged, and organized contracts with key terms summarized all cut down on follow-ups. It doesn’t have to be perfect, just accurate and organized enough that it looks like management operates a well-run business, not like it was thrown together the week the LOI was signed.
Bottleneck Two: Change-of-Control Provisions Nobody Mapped Before LOI
This one frequently catches sellers off guard. Many business contracts, particularly customer agreements, lease agreements, and key supplier contracts, contain change-of-control provisions which require the other party’s consent before ownership can transfer. If nobody identifies those clauses before the LOI, they show up in diligence.
Consent requirements are common, and they’re usually manageable. The issue is when you find out about them. Say you learn halfway through diligence that three of your top ten customers need to sign off. Everything slows down while you have those conversations. Some customers reply in a day. Others take weeks, and a few will want to renegotiate. That’s all normal, but once it starts, no amount of financial prep gets the time back.
The fix is to review contracts before you go to market. Your M&A attorney should map every material agreement for change-of-control language, assignment restrictions, and termination rights triggered by a sale. If you know about these provisions before the buyer does, you have options: you can begin consent conversations earlier, structure the transaction to work around certain provisions, or at minimum build realistic timing into the LOI. Find them in week four, with the buyer’s team already in the data room, and you have far fewer options.
Bottleneck Three: Owner Distraction
This one doesn’t get talked about enough. Diligence takes a lot of the owner’s time: the data room, buyer questions, calls with advisors. While that’s happening, the business tends to slip. Sales soften, a key account gets less attention, and a problem that would normally get caught early sits for a few weeks.
The timing could not be worse. The buyer is watching the business more closely during diligence than at any other point in the process. A dip in performance during diligence gives the buyer a reason to revisit price, ask for additional reps and warranties, or hold off until they can tell whether it’s a trend or a blip. A 90-day process becomes 120 days while everyone waits for another month of financials.
You can’t ignore the transaction, but you can hand most of it off. An experienced M&A advisor runs the data room, coordinates DDQ responses, and handles day-to-day communication with the buyer, so you can keep running the company. Owners who try to do both usually find that both suffer. For us, that’s one of the strongest reasons to hire an advisor, apart from anything to do with price. You can see how we handle this in Viking’s process overview.
Bottleneck Four: Buyer Scope Creep That Was Not in the LOI
Good preparation is necessary, but it won’t protect you from everything. A seller with a spotless data room can still end up in a 120-day process when the buyer runs more workstreams than the LOI timeline assumed.
In our experience, buyers, especially private equity groups, are asking for more than they used to. Cybersecurity reviews, market studies, deeper customer concentration analysis, and heavier quality of earnings (QoE) work now show up in deals that wouldn’t have needed them a few years ago. A QoE scoped for three weeks can take six if the accounting firm finds areas that need more documentation. That isn’t the seller’s fault, and the seller can’t stop it.
What sellers can control is their response. When the scope grows, you can wait to hear what comes next, or your advisor can stay in regular contact with the buyer’s team to manage the timeline, track open items, push for reasonable response dates, and speak up when things start to drift. That choice affects how long the deal takes and how much leverage you have at the end. Long diligence wears sellers down, and worn-down sellers tend to accept worse terms. Knowing that going in makes it easier to hold your ground.
How the Delays Add Up
These four problems feed each other. A disorganized data room leads to a longer DDQ. A longer DDQ drags out the timeline. A longer timeline pulls the owner further from the business, the business slips, and the buyer has grounds to reopen terms. Any one of these is manageable. Together, they can turn a 90-day process into six months and leave you negotiating a very different deal from the one you signed at LOI.
The sellers who move through diligence efficiently understand that diligence is something you manage, not something you survive. That means having a clear picture of what buyers will ask for before they ask, mapping your contract obligations before they surface as surprises, keeping the business running while the transaction is in progress, and having an advisor who manages the process so you don’t have to manage it alone.
If your timeline has already slipped and you’re not sure what to focus on, talk to an M&A advisor who has been through this many times, and do it soon. Viking M&A has worked with sellers at every stage of this process, including those who came to us mid-diligence when momentum had already stalled. There is no obligation in a conversation, and you’ll come away with a clearer sense of where you stand.
Frequently Asked Questions
Due diligence typically runs 60 to 90 days from LOI to closing in the lower middle market, but it can often take longer if not managed properly. The IBBA/M&A Source Market Pulse has consistently reported about three to four months from LOI to close. The actual timeline depends heavily on how organized the seller’s documentation is, whether any contract consent requirements surface, and how actively both sides manage the process.
In our experience, the four most common causes are: a disorganized data room that generates more buyer questions than necessary, change-of-control provisions in contracts that require third-party consent before the business can transfer, owner distraction that allows business performance to slip while the buyer is watching, and buyer-side scope expansion where the buyer adds workstreams that were not anticipated in the LOI timeline.
Yes, and the seller’s preparation is the single biggest variable within their control. Organizing the data room thoroughly before the buyer enters it, conducting a contract review to identify change-of-control provisions early, and delegating transaction management to an advisor so the owner can stay focused on running the business all reduce timeline drag meaningfully.
Extended timelines create seller fatigue, and fatigued sellers often accept worse terms than they would have early in the process. A long diligence period also increases the risk that business performance softens while the buyer is watching, which can give the buyer grounds to revisit price or request additional protections in the purchase agreement.
A well-organized data room does not just reduce the time spent answering questions. It signals to the buyer that the business is well-run, which reduces the buyer’s perceived risk and the intensity of their scrutiny across other workstreams. A disorganized data room has the opposite effect: it signals that more careful review is needed, which extends the process.
A DDQ is the formal list of questions and document requests a buyer sends after an LOI. In lower middle market deals, it can run to hundreds of items across financial, legal, operational, and customer workstreams. When the seller’s team must respond to all of it simultaneously while still running the business, response cycles can stretch by weeks. Sellers with a well-prepared data room get fewer follow-up questions because many answers are already in the documents on file.
Change-of-control provisions are contract clauses that require a counterparty’s consent before the business can be transferred to a new owner. They appear in customer agreements, leases, supplier contracts, and franchise agreements. When these provisions are discovered mid-diligence rather than before going to market, the consent process adds weeks of back-and-forth that the LOI timeline did not account for.
An experienced M&A advisor or business broker manages the data room, coordinates DDQ responses, and handles day-to-day buyer communication so the owner can stay focused on running the business during the transaction. Sellers who manage the process themselves while also running operations typically see business performance slip during the exact window when the buyer is watching most closely. Professional representation addresses both the timeline and performance risk at the same time.