Contents
- The real risk of a plant merger is not legal, it is operational
- What an interim manager manages in concrete terms in an industrial
- Before, during, after: the three stages of the mission
- A real-life example of operation
- WAYDEN in Lyon for your external
- FAQ
- Sources
merger
preparation
growth operations
The real risk of a plant merger is not legal, it is operational
The market for mergers of SMEs and mid-caps remains active despite the economic situation: according to the In Extenso Finance panorama relayed by Option Finance, 1,076 transactions were recorded in France in 2025, and build-up strategies (successive acquisitions to consolidate a group) now represent 43% of transactions, compared to 32% a year earlier. Many of these arrangements lead to the same project: to bring together two industrial tools.
And this is where it gets complicated. Lawyers and bankers go home after closing; duplicate references, deviations from collective agreements, incompatible ERPs and team concerns remain. In a dense industrial region such as Lyon, where national manufacturing production fell by 1.0% in May 2026, an integration that gets out of hand is paid for directly in lost customers.
The current manager already has a site to run. Entrusting him with the integration in addition to this weakens both. Companies have understood this: according to a European survey in the spring of 2025, 44% of them planned transition assignments dedicated to change management and restructuring. Our article on the reasons to call on an interim manager during a merger-acquisition develops this observation.
What an interim manager manages in concrete terms in an industrial merger
The interim manager arrives with a clear mandate: to succeed in the integration, without any other agenda. This neutrality is precious when two organizations, two management and sometimes two historical shareholders are gauging each other.
Its standard scope covers four areas. Firstly, industrial harmonisation: mapping the flows of the two sites, deciding which specialises, transfers or mutualises. Then the social aspect: information-consultation of the authorities, harmonisation of statuses, support for mobility, in compliance with the legal calendar. Systems and data: converging ERP, production management and reporting to steer everything with reliable figures. Finally, culture: creating mixed teams, common rituals and quick victories that give substance to the rapprochement.
For the most sensitive operations, this management is linked to the steps detailed in our guide to how to make a successful M.
Before, during, after: the three stages of the mission
Before closing: preparing for integration and making data more reliable
The best assignments start before the signing. The interim manager contributes to the preparation of the operation: reliability of industrial and financial data, supply of the data room (the secure document space made available to buyers), identification of realistic synergies and execution risks. This work avoids discovering after the fact what should have weighed in the negotiation.
The first hundred days: secure and decide
After closing, everything is decided quickly: naming the target organizations, securing customers and strategic suppliers, dealing with duplicates in a fair and announced manner. The interim manager keeps the integration plan, arbitrates the issues that block and protects the operational teams from over-solicitation.
The following months: realising synergies and passing on
The synergies promised at the time of the deal are materialized in this phase: pooling of purchases, specialization of lines, convergence of systems. The mission ends with a handover to long-term management, with a documented system, as for any restructuring carried out in stages.
A real-life example of operation preparation
A recent case, anonymous, illustrates the role of the interim manager upstream of a transaction. A group in the healthcare sector decided to sell two subsidiaries to refocus on its core business. One of them, built through successive acquisitions, has such a heterogeneous history that potential buyers are unable to read the real performance of the activities.
An interim manager is mandated to structure all the data necessary for the sale: collection from multiple sources, constitution of a reliable repository, feeding of the data room managed by the investment bank, all while preserving the daily functioning of the teams. This missing link between strategic intention and execution is exactly what interim management brings to external growth operations.
WAYDEN in Lyon for your external growth operations
Within its pool of 8,000 managers, WAYDEN mobilizes profiles that have already led industrial integrations: general managers, industrial directors, CFOs seasoned in capital operations. These managers have 15 to 25 years of experience and start in less than a week.
In the Lyon region, the firm knows the industrial areas concerned by the mergers: chemicals, mechanics, plastics, agri-food. Each mission is supervised by an associate director, from the initial scoping to the transfer. The regional system is detailed on our interim management page in Lyon.
FAQ
When should the interim manager be involved in a factory merger?
Ideally before closing, as soon as the operation becomes likely: he contributes to the preparation, makes the data reliable and builds the integration plan. Otherwise, in the very first weeks after the signature, when the organizational decisions are not yet fixed and the teams are waiting for a direction.
Does the interim manager replace the managers of the two sites?
No, unless there is a vacancy to be filled. He manages the integration program with the support of the management in place, which allows them to remain focused on operations. His position as a third party facilitates arbitrations between the two organizations, without any suspicion of favoritism.
How to manage the social aspect of a merger of two factories?
By scrupulously respecting the legal calendar for information and consultation of representative bodies, and by dealing early with issues of concern: harmonization of statutes, becoming duplicates, mobility. An experienced manager knows how to sequence these subjects and document each step to secure the operation legally and humanly.
What indicators should be monitored to judge the success of integration?
There are three families: continuity (customer service, quality, safety, throughout the operation), synergies (purchasing gains, line specialization, convergence of systems, measured against the initial plan) and human (unwanted departures, absenteeism, social climate). A successful integration holds all three at the same time.
Conclusion
A merger of two plants is not judged at closing, but eighteen months later, on the synergies achieved and the customers retained. Entrusting this management to a dedicated and experienced manager means giving the operation the means to keep its promises, while your teams continue to run the sites.
Are you preparing or have just concluded an industrial merger in the Lyon region? Contact WAYDEN to discuss with an associate director and meet interim managers experienced in post-acquisition integrations.
Sources
- Option Finance, “The number of SME mergers and acquisitions fell by 12% in 2025” (In Extenso Finance overview), published on 30 April 2026: 1,076 transactions recorded in 2025, build-up in 43% of transactions (compared to 32% in 2024), acquiring investment funds in 20% of cases.
- INSEE, “In May 2026, manufacturing production fell by 1.0%”, Informations rapides n° 166, published on 3 July 2026: manufacturing production down by 1.0% in May 2026.
- TPE Actu, “Companies and the use of interim management”, published on 8 May 2025: 44% of companies planned change management and restructuring missions in 2025.
