01. Why choose acquisitive growth?
There are two ways to grow a business. Organic growth — winning customers, opening branches, launching new offers — builds over time but moves at the pace of the market. Acquisitive growth — buying existing companies — lets you step up a level in a few months rather than several years. The two are not opposed: the strongest trajectories combine them, and a buy-and-build strategy is the most structured way to do so.
What an acquisition brings immediately
- A denser geographic footprint: each target comes with its sites, local teams and knowledge of the ground.
- Complementary customer portfolios: recurring revenue acquired from day one, with no customer acquisition cost.
- New expertise and new business lines: know-how that would take years to develop in-house.
- A mechanical acceleration of revenue: the acquired scale improves bargaining power, commercial credibility and access to key accounts.
- Entry into new regions: setting up by buying an established local player is faster and less risky than starting from scratch.
You still need to know how to execute. Buying is simple on paper; creating value from acquisitions is a profession in its own right. To understand what separates a successful buy-and-build from a collection of poorly integrated companies, this guide analyses a real and recent case: NSI Groupe, a mid-sized company from northern France that has become, in just a few years, one of the most active consolidators in its sector.
02. NSI Groupe: the trajectory
Founded in 2012 in Marly, near Valenciennes, by Romain Tellier — then aged 24 — NSI Groupe (formerly Nette Services) is a commercial cleaning specialist that has become a multi-service provider: cleaning, landscaping, front-of-house services and pest control. Describing itself as the 21st-largest cleaning company in France, the group is aiming for the top 15 from 2026 and the top 10 in 2028.
Fourteen years in three phases
The foundations. Nette Services is founded; the operating culture, customer proximity, staff training and local roots are built. In 2017, the Argenteuil branch opens — the first site outside the Hauts-de-France region.
The turning point. Acquisition of HPS and creation of the NSI Groupe brand; a branch opens in the Oise. The company no longer grows only through its own branches: it buys to accelerate.
Acquisition of Dôme Service; the Clermont-Ferrand branch and the in-house training centre open.
Acquisition of PNS.
Acquisition of Gestipro (cleaning, Île-de-France, EUR 16 million in revenue): a change of scale.
EUR 80 million in revenue. Acquisitions of Thiebat and JLP Services, then GPNI in Bordeaux (300 employees, EUR 4.5 million in revenue): the first foothold in western France, a priority area. Five branches opened organically, launch of NSI Luxury, purchase of the Château d'Aubry-du-Hainaut.
Acquisitions of RM Propreté near Rouen (100 employees, EUR 1.8 million in revenue), AS Hub Propreté (Île-de-France, EUR 6 million), ABC Entretien (mainland France and French overseas territories, EUR 18 million) and EPSO (EUR 6 million). The group reaches EUR 120 million in revenue and 6,500 employees, with around thirty sites in France and the Indian Ocean.
03. Analysis: the buy-and-build choices that make the difference
1. A clear, repeatable acquisition thesis
NSI favours acquisitions linked to the owner's retirement: healthy companies, a motivated seller, a succession that can be prepared. Targets remain a digestible size relative to the group, with one constant criterion: strengthening the national footprint or completing a business line. This discipline avoids opportunistic deals that divert energy from the plan.
This thesis translates into several different acquisition criteria depending on the strategy: there is no single criterion of size, location or activity, but rather several combinations of these criteria, to take each strategy into account alongside the parallel development of organic growth.
These points are the cornerstone of how the project is structured.
2. Credibility as a deal-flow engine
After some twenty successful deals, the group now regularly receives files from sellers. Its reputation as a serious acquirer — one that integrates well, respects teams and honours its commitments — becomes a competitive advantage in sourcing: the best targets come to you before they reach the market.
3. An ambitious, proactive project
NSI was not only approached by sellers: it decided to map every company matching its criteria and contact them to create opportunities. This proactive approach is at the heart of Collaboration Capital's work on the project, which built a steady pipeline of target companies to feed it.
Beyond the numbers, targeting off-market deals made it possible to build privileged discussions with sellers, without competing against many buyers.
4. Integration turned into a system
This is the most distinctive feature of the model. All employees joining the group — including those from acquired companies — go through NSI Learn, the in-house training centre in Valenciennes, where the company was born: 1,750 trainees in 2025, and a EUR 1.5 million investment in a new 700 m² building with technical training floors. The group even bought the Château d'Aubry-du-Hainaut to host employees during their onboarding and bring teams together. In a labour-intensive sector where value lies in contracts and teams, cultural integration is not a luxury: it is the condition for retaining the acquired revenue.
5. Organic growth remains key
NSI keeps opening its own branches and diversifying around its core business with subsidiaries created in-house — landscaping (NSI Green), front-of-house services (NSI Hospitality), cleaning for luxury boutiques (NSI Luxury) — to offer a complete service. Acquisitions accelerate a machine that already works; they do not replace it.
04. Key takeaways — and pitfalls to avoid
The NSI case is not limited to mid-sized cleaning companies. The principles behind its success apply to any SME considering a buy-and-build, whatever its sector.
TO REPLICATE
- Write a long-term strategic plan and share it with your teams: every acquisition must have its place in it.
- Define a precise acquisition thesis: type of targets, sizes, geographies, situations (owners retiring…) — and stick to it.
- Treat integration as a profession: onboarding, training, cultural integration. A target's value lies in its teams and its customers.
- Sequence: acquire, digest, then start again. NSI resumes acquisitions "once the latest deals have been digested".
- Keep a powerful organic engine: it funds development, reassures lenders and proves the quality of the model.
- Build your reputation as an acquirer: it is what generates proprietary, off-market deal flow.
TO AVOID
- Buying opportunistically, without an industrial rationale: a target that does not serve the plan is always expensive.
- Neglecting people and culture: in services, the main asset can walk out of the door. Without integration, acquired revenue evaporates.
- Overpaying or over-leveraging: the price and financing structure must remain compatible with consolidated debt service capacity.
- Chaining deals without digesting them: each integration takes up management time; piling them up erodes quality and profitability.
- Skipping due diligence: employment liabilities, customer dependency, contracts, litigation — bad surprises are paid for after completion.
- Betting everything on acquisitions: growth that is purely acquired often masks a flagging organic model.
05. Taking action: the buy-and-build method
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1
Strategy and acquisition thesis.
Clarify the objective (territories, business lines, critical mass), the target criteria and the financial capacity available.
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2
Sourcing and approaching targets.
Identify and qualify targets — including off-market — then approach their owners discreetly and methodically.
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3
Analysis and valuation.
Assess the target on the basis of documents: financial performance, revenue recurrence, dependencies, realistic synergies, price range.
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4
Structuring the financing.
An acquisition is rarely financed with equity alone: senior bank debt, vendor financing, private debt, quasi-equity or a minority equity raise. The right structure preserves cash and the ability to complete the next deals.
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5
Negotiation, letter of intent, due diligence.
Secure the agreement in a letter of intent (LOI), then carry out financial, tax, employment and legal due diligence before any final commitment.
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6
Completion and integration.
Sign, then execute the integration plan prepared upstream: communication to teams and customers, harmonisation of processes, tracking of synergies.
Collaboration Capital supports you
An independent M&A and business finance advisory firm based in Marseille, Collaboration Capital advises owners of SMEs and mid-sized companies (from EUR 1 million in revenue), in France and internationally, on transactions of EUR 1–200 million:
- Acquisition (buy-side): thesis, target sourcing, valuation, negotiation, execution;
- Business sale (sell-side): preparation, valuation, buyer search, negotiation;
- Financing: putting banks, debt funds and family offices in competition to obtain the best offers.
Our approach is built on a proprietary platform and artificial intelligence tools dedicated to sourcing targets and lenders: more data, more speed, better decisions.
310 rue Paradis, 13008 Marseille, France — Tel.: +33 4 91 48 16 53 — collaborationcapital.org
Collaboration Capital is an independent M&A and finance advisory firm, registered with ORIAS (the French register of insurance, banking and finance intermediaries) as a banking and payment services intermediary (IOBSP) under number 25000696 (www.orias.fr). Non-contractual document for educational purposes, prepared in September 2026 from public information about NSI Groupe (group communications and regional business press) and public sector data (Fédération des entreprises de propreté, Bpifrance Création). Collaboration Capital was not involved in the NSI Groupe transactions cited as examples. A company's past performance is no guide to the results of an acquisitive growth strategy.