Buyers hiring M&A consultants are usually solving one of two problems, and the firms that solve them are rarely the same. Getting the deal done and making the deal work afterwards are different disciplines, and the advisor who runs an excellent process frequently has no integration capability at all.
Buyers who hire for the first and assume it covers the second discover the gap around day 60, which is when the integration plan was supposed to already exist.
Most of the value destruction in mid-market M&A happens after the deal closes, in the integration nobody planned before signing.
This guide covers the four jobs M&A consultants are hired for, 7 firms and what each is built for, where mid-market integrations break, how to plan and measure the integration, and the appointment buyers most often regret skipping.
It is written for deal teams, operating partners and portfolio company chief executives working on transactions from $30M to $500M in enterprise value.
The Four Jobs in a Transaction
The work M&A consultants cover divides into four, and no single firm is strong across all of them.
- Sourcing and process. Finding targets, running the auction, managing the negotiation. Investment banks and origination specialists.
- Diligence. Testing whether the business is what the seller says, across financial, commercial, technical and operational workstreams.
- Integration planning. Deciding before close what will be combined, what will be left alone, and in what sequence. The workstream most frequently compressed.
- Integration execution. Doing it, over 6 to 18 months, while both businesses continue to operate.
A firm that runs an excellent process may have no integration capability. That is a reason to plan the second appointment before it is needed, rather than a criticism of the first.
Where Mid-Market Integrations Break
Four failure patterns account for most of the damage.
- Systems that will not reconcile. Two CRMs, two billing platforms and two charts of accounts produce three versions of revenue. Until they agree, synergy tracking is guesswork and the board loses confidence in the reporting.
- Customer attrition nobody predicted. Integration changes the buying experience. Without customer-level visibility, the churn appears a quarter after it becomes irreversible.
- Key people leaving in month four. Retention packages usually cover the executive team and rarely the individuals who hold operational knowledge.
- Synergies claimed rather than realised. The model number was net of costs and the tracking is gross, so the reported figure looks fine while the profit and loss statement does not move.
7 M&A Consultants and Integration Firms for the Mid-Market
Seven firms operating across the deal lifecycle, described by what each is structurally built to deliver.
1. Alvarez & Marsal
Alvarez & Marsal runs post-merger integration alongside its operational restructuring practice, with people who take interim roles inside the combined business rather than advising from outside. The willingness to hold an operating seat is the differentiator where the integration needs decisions made rather than recommended.
Built for: integrations needing operational leadership as well as programme management.
2. DevriX
DevriX covers the technical and revenue systems side of integration: combining CRM and billing platforms, consolidating data and reporting, and rebuilding the revenue operations the merged business runs on.
This is where mid-market integrations most often stall, because two companies with different systems produce numbers that will not reconcile and the board loses confidence in the reporting. Advisory sits with Async Advisor and Growth Shuttle; the DevriX private equity practice builds under a separate contract with a 40-person team.
Built for: platform and add-on integrations where systems and data are the binding constraint.
3. AlixPartners
AlixPartners brings integration management office capability and the bench to run several workstreams simultaneously under a synergy deadline. The scale suits the integration where several functions have to move at once and a defended synergy number is driving the clock.
Built for: complex integrations with a synergy number to defend.
4. Accordion
Accordion concentrates on the finance function through a transaction: reporting integration, FP&A and the systems the combined finance organisation will run on. It fits the integration where consolidating the reporting is the critical path and everything else waits on it.
Built for: integrations where finance consolidation is the critical path.
5. West Monroe
West Monroe pairs integration planning with technology capability, covering systems consolidation alongside the operating model work. The technology depth suits the integration where the combined business runs on software the acquirer inherits rather than understands.
Built for: technology-enabled integrations.
6. Grant Thornton
Grant Thornton provides transaction advisory and integration support to the middle market, coordinating with its financial diligence practice. The single-provider model reduces the number of independent workstreams a stretched management team has to service.
Built for: buyers wanting one provider across diligence and integration.
7. RSM US
RSM covers transaction advisory and post-close integration for middle-market acquirers, including technology and process consolidation. The middle-market focus means the methodology is scaled to the platform rather than borrowed from large-cap programmes.
Built for: middle-market platforms running an add-on programme.
Planning the Integration Before Close
The cheapest workstream in a deal is the one most often skipped: deciding, before signing, what will be combined, what will be left alone, and in what order. An integration plan built after close is a plan built while the clock on the synergy case is already running.
The plan that works names three things before day one. What integrates immediately, usually the back-office systems and reporting where duplication is pure cost. What integrates on a defined schedule, typically customer-facing systems where a rushed migration risks the revenue. And what stays separate, because the acquired business runs better left alone and forcing it into the platform destroys the value that justified the purchase. A plan that treats every function as an immediate merge is as damaging as one that merges nothing.
The decision of what to leave separate is the one most often got wrong. Acquirers default to full integration because it is where the modelled synergies sit, and they underweight the revenue that depended on the acquired company operating as it did. The discipline is to integrate the back office aggressively, integrate the customer-facing systems carefully, and leave the parts that were the reason for the purchase alone until there is evidence that combining them adds rather than removes value.
The First 100 Days
Integration momentum is set in the first 100 days, and the sequence matters more than the speed.
The first move is establishing a single source of truth for the numbers, because until the two businesses report on the same basis every synergy claim is contested and the board discounts the reporting. The second is retaining the people who hold operational knowledge, which means identifying them before close rather than reacting to a resignation in month four. The third is the two or three integration steps that are both low-risk and visible, which build confidence across both organisations that the combination is working.
What does not belong in the first 100 days is the hardest system migration. Attempting it before the reporting foundation exists means running the riskiest change with no reliable way to measure whether it worked.
Measuring Synergy Realisation
The number in the model is net of the cost to achieve it. The number most integration teams report is gross. That gap is where a mid-market integration reports success the profit and loss statement never shows.
Realised synergy should be tracked net of realisation cost, against the specific figure underwritten, and reported on a fixed monthly cadence with the variance explained. A synergy claimed in a slide but not visible in the management accounts is an activity rather than a result. The discipline is unglamorous, and it is the difference between a synergy case that holds at the next valuation and one that erodes while the reporting says otherwise.
How to Structure the Appointments
For a mid-market platform acquisition, the sequence of M&A consultants that works is consistent. Appoint the bank or origination advisor for the process. Commission diligence by discipline, with technical and operational scoped to produce a costed remediation list rather than a description. Bring integration planning in before close, so day one is a plan rather than a scramble. Then keep whoever assessed the systems through the integration itself, because they already know where the problems are and starting again costs the 60-day discovery period.
The appointment sequence is also a budget decision. Spending the whole advisory budget on the deal and nothing on the integration is the most common allocation error, and it is backwards: the process determines whether you buy the business, but the integration determines whether the purchase returns the model.
Five Mistakes That Damage an Integration
- Skipping integration planning before signing. The cheapest workstream in the deal and the one that determines whether the synergy number arrives.
- Treating synergy tracking as gross. A number net of costs in the model and gross in the tracking overstates realisation until the profit and loss statement contradicts it.
- Retention packages that miss the operators. Covering the executive team and not the individuals who hold the operational knowledge.
- Two providers for assessment and execution. The handover loses the detail that made the assessment useful.
- Assuming the systems will reconcile. They rarely do on their own, and unreconciled systems make every downstream number contested.
Matching the Firm to the Situation
- Operational leadership needed inside the business: Alvarez & Marsal.
- Large multi-workstream synergy programme: AlixPartners.
- Finance consolidation is critical path: Accordion.
- One provider across diligence and integration: Grant Thornton or RSM US.
- Systems and data are the constraint: DevriX.
If a live deal has something in the data room that does not reconcile, that is the Pre-LOI Check. For the on-call bench through a deal, M&A Advisory Support. Sponsors are searchable in the PE Firm Index directory.
The Question Worth Asking Every Candidate
Ask how the firm tracks synergies once the integration starts.
A firm that tracks them net of realisation cost, against the number in the model, and reports the gap monthly is doing the work. A firm that reports gross synergy activity is producing a number that looks like progress while the profit and loss statement stays flat, which is the most common way a mid-market integration reports success it did not achieve.