Key highlights:
- High failure rates: Roughly one-third of signed LOIs in the lower middle market never close.
- Diligence risks: Quality-of-earnings (QoE) discrepancies killed 21.3% of deals in 2025, double the rate from 2023.
- Leverage shift: Exclusivity periods (typically 45 to 90 days) strip sellers of competitive tension.
- Value preservation: Seller preparation, particularly Vendor Due Diligence (VDD), can save 15 to 20 days in transaction closure and defend against price re-negotiations.
It’s half past eight on a Tuesday evening. The founder sits alone in the conference room, staring at the signed Letter of Intent. The number is good and months of preparation have led to this moment. The champagne is in the fridge while the lawyers are drafting press releases, yet what the founder doesn’t realise is that the hardest part hasn’t started yet.
The signed LOI isn’t the finish line; it’s the beginning of the most precarious 90 days of the entire transaction.
Most M&A transactions collapse, get repriced, or bleed value between signing a Letter of Intent and closing. 25% to 35% of signed LOIs in the lower middle market never close at all. Culprits are operational distraction, talent attrition, and late-stage re-trading that destroy seller value during the exclusivity window, the exact moment when competitive leverage vanishes.
Professional M&A advisors protect sellers through strategic ring-fencing, vendor due diligence, talent retention planning, and defensive negotiation tactics that preserve deal value through closing.
The structural asymmetry of the exclusivity period
What exclusivity actually means for sellers
The exclusivity clause, often called a “no-shop” provision, is one of the few legally binding elements in an otherwise non-binding letter of intent. Once signed, it prohibits the seller from negotiating with other buyers for a defined period, typically ranging from 45 to 90 days.
From the buyer’s perspective, exclusivity protects their heavy investment in due diligence, From the seller’s perspective, however, signing exclusivity is an asymmetric act, as the moment that signature dries, the competitive tension that drove the buyer to the table begins to dissipate.
In 2021, only around 6% of deals involving exclusivity periods had a duration of 61 days or more. By 2022, nearly 40% had durations of 61 days or longer, and most extended well beyond 76 days. To put this in perspective, research consistently estimates that 70% to 75% of M&A deals fail to create shareholder value for the buyer. In the 2026 M&A environment, this trend continues to accelerate and due diligence windows keep expanding as buyers face greater macro uncertainty and regulatory complexity.
The leverage inversion mechanism
Research consistently estimates that between 70% and 90% of M&A deals ultimately fail to create their expected shareholder value. However, immediate deal collapse before closing usually stems from a few predictable failure modes:
| Failure Mode | Impact on the Transaction | Defence Strategy |
| Operational distraction | Management focuses on diligence, causing quarterly revenues to soften. Buyers use this drop to justify a lower price. | Ring-fence the deal team from the core sales function. |
| Talent flight | Headhunters target key staff immediately after deal rumours surface. Replacement costs run 2x to 4x an annual salary. | Implement retention bonuses conditional on closing. |
| QoE discrepancies | Due diligence reveals earnings gaps. This caused 21.3% of LOI failures in 2025, double the rate seen in 2023. | Commission a robust Vendor Due Diligence report. |
| Late-stage re-trading | Buyers attempt to lower the enterprise value or shift risk to the seller via earnouts once exclusivity sets in. | Maintain strict milestone deadlines within the LOI. |
Defensive tactics: how sellers can protect themselves
Each of these failure modes is manageable during the M&A process with the correct structure and professional guidance.
1. Ring-fence the sales function
The most immediate operational risk after LOI signing is that the revenue engine slows because the people who run it are now running due diligence responses. The sales function should be explicitly separated from the deal process. The Chief Revenue Officer should remain focused entirely on hitting revenue targets. Closing the pipeline through the diligence window is a prime valuation defence.
2. Appointing a separate diligence lead
The CEO should not manage due diligence; deploying the CEO’s bandwidth entirely on data room queries guarantees the business will suffer. Instead, appointing a dedicated diligence lead, typically the CFO or a transaction director, to act as the single point of contact, is a sensible model.
3. Utilising vendor due diligence
Vendor due diligence (VDD) is one of the most powerful, and most underutilised, tools available to sellers in a mid-market M&A process. VDD means commissioning an independent due diligence report on your own business, conducted by a reputable firm, and sharing it with prospective buyers under a reliance letter.
It controls the narrative, typically saving between 15 and 20 days in transaction time and severely constraining a buyer’s ability to claim “surprise” diligence findings to justify a price reduction. Best practice suggests that VDD-prepared deals may close faster and may capture higher valuations.
4. Proactive talent retention planning
Given the documented risk of headhunters targeting key staff shortly after announcement, talent retention planning must begin before the LOI is signed, ideally as part of the pre-deal preparation process. Structured retention arrangements for key employees are a standard mechanism to reduce flight risk during the exclusivity window.
5. Managing representations and warranties carefully
One of the most technically complex aspects of the LOI-to-close window is the negotiation of representations, warranties, and indemnities in the definitive purchase agreement.
Research notes that breaches of representations and warranties, where the buyer claims the seller’s guarantees were false or inaccurate, are among the most common M&A disputes. Sellers without dedicated legal counsel experienced in M&A purchase agreements frequently make concessions that look minor at the drafting stage and prove consequential post-closing. Getting this right requires financial advisory expertise, not just legal expertise, and is one of the clearest demonstrations of what a well-resourced sell-side adviser protects against.
What professional M&A advisors protect against
If a founder has engaged an experienced M&A advisory boutique, the 90 days post-LOI look completely different. The advisory team ring-fences the sales function, shares the VDD package, and negotiates the working capital mechanism defensively to prevent true-up gaming.
The headline price in the LOI is the beginning of the negotiation, not the end. What the seller takes home on closing day is determined entirely by what happens in the 90 days between. That is why founders who understand this structural reality engage advisors before the process begins, not after the problems surface.
Contact us for more information on VDD today.
