Buy-and-Build Strategy: How PE Platforms Price Add-Ons

Going into 2025, add-ons made up three in four US private equity buyouts, according to BDO, and they're the engine of a buy-and-build strategy: a private equity fund buys a platform company, then grows it through a series of smaller add-on acquisitions. The return depends on the price paid for each add-on and on integration, far more than on size.

spectup runs add-on searches for sponsors and their platforms, on the acquirer's side only.

How a buy-and-build strategy works: platform, add-ons, exit

Bain's 2024 private equity report defines buy-and-build as using a well-positioned platform "to make at least four repeated add-on acquisitions of smaller companies." The platform is the first and usually the largest deal: a company with the management, finance function and market position to absorb businesses it hasn't bought yet.

An add-on is the umbrella term for any company the platform buys after it: a bolt-on keeps its own identity inside the group, and a tuck-in is absorbed completely. At exit the fund sells the combined group at a multiple that should reflect its size, its spread of customers and the quality of its reporting.

The add-ons are where the return is made or lost, and the best of them come from owners who weren't planning to sell. A platform without its own corporate development team buys that sourcing capacity in, which is the job of buy-side M&A advisory.

Is a roll-up strategy the same as buy-and-build?

The market uses the two terms interchangeably. The difference that matters to a lender, an owner and an exit buyer is what sits at the centre.

A buy-and-build strategy starts from a platform with management, systems and a commercial plan, and each add-on is chosen to fit it. A roll-up strategy often combines many similar small companies at once or in quick succession, sometimes with no real platform underneath. Bain's 2024 report notes that most roll-ups focus on capturing regional market share.

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Does multiple arbitrage still pay?

Multiple arbitrage is the gain from buying earnings at a low multiple and selling them inside a larger company at a higher one. Bain describes it as creating a large, high-multiple company by tucking in add-on acquisitions at lower multiples. In the example below, the gap between a 6x add-on and a 10x exit is what the arbitrage pays, before fees, debt costs and integration take their share.

In Bain's 2024 analysis of 44 buy-and-build deals made between 2010 and 2019, those relying on multiple arbitrage alone returned an average 1.4x MOIC (multiple on invested capital), while those with a strategic rationale for faster organic growth or meaningful margin improvement returned 2.2x.

Organic growth and margin gains compound across every company in the group, while arbitrage is captured once per deal and only if the exit multiple holds. Bain's example of the strategic kind is a carve-out whose sponsor linked its add-ons to a commercial plan and moved the whole group onto one ERP and IT system.

A buy-and-build strategy example: what four add-ons are worth at exit

Illustrative example: a platform with $10M EBITDA is bought at 10x, four add-ons with $6M EBITDA between them follow, and integration adds $1M of cost savings, for $17M of combined EBITDA. The numbers are rounded to show the mechanism and describe no real transaction.

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All four rows are before fees, debt service and organic growth. A one-turn lower exit halves the gain, paying auction prices for the add-ons takes almost as much, and the two together leave $2M on a $151M outlay.

The add-on price is the one line in the table management controls, and it's decided at sourcing, which is where the 6x or the 8.5x comes from.

Bolt-on, tuck-in or transformational: which add-on acquisition fits?

Add-on acquisitions come in four types, from a tuck-in acquisition the platform absorbs completely to a transformational merger with a company of similar size. Most programmes are built from tuck-ins and bolt-ons, and the type of each deal fixes the integration bill before the price is agreed.

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A geographic add-on is often run as a bolt-on acquisition, with its local name kept. In 2023 spectup ran the buy side on a distribution business bought for its geography, picked from a universe of forty that was screened on ownership structure before anyone was contacted.

What makes a company a platform that can carry add-ons?

A platform's weaknesses, such as a stretched finance team or two ERPs, get worse with each add-on. Bain's 2024 report treats growth potential and sufficient white space for acquisitions as the entry ticket for a buy-and-build strategy in any sector. Whether this company can lead the programme is a separate, internal test.

1. Management that has integrated before, or can hire someone who has, because the first add-on is where the playbook gets written.

2. A finance function with spare capacity, so each new entity is consolidated before the next one closes.

3. Systems that absorb sites and staff: one ERP, one payroll, one reporting pack.

4. A fragmented market with enough owner-managed companies of the right size and quality to fill the programme; spectup takes a search only when the universe holds at least twenty credible targets.

5. Credibility with owners, so that a call from the platform is one a seller takes seriously.

The sectors that pass these tests tend to be service-heavy and regionally fragmented: building and facility services, IT managed services, testing and inspection, specialty distribution and healthcare practices.

Sponsors still looking for the platform itself have a different problem, and it's the one a deal origination mandate solves, with spectup approaching companies on the fund's behalf.

Where add-on targets come from, and why off-market sourcing protects the price

Most good add-on targets are owner-managed and not for sale. A company that has never run a process has simply never been asked, so the first serious approach decides whether the platform pays the 6x of the example or meets the same company later in an auction at 8.5x.

Off-market, the buyer sets the timetable, price discovery happens between two parties, and there's room for structure: earn-out, rollover, staged payment. In a running process the same company asks for a best offer, on its advisor's date, against three to ten others.

Who owns the business, whether there's a successor and whether outside capital is already in it decide whether that conversation is possible this year. The approach itself protects the price too: on a 2023 bolt-on in building products, an owner-managed installer was approached directly on a succession trigger, with the acquirer's name withheld until the second conversation.

From the desk. Society Brands, a US consumer-brand aggregator, grows by buying brands and running them on one platform. spectup worked its buy side on the acquisition of Crunchi, a consumer brand that was never on the market, a $12M transaction that closed and sits on our published M&A ledger.

“Their work significantly expanded our access to potential acquisition targets and helped us identify and engage with opportunities we wouldn’t have found otherwise.”

Laurent Truc, SVP Business Development, Society Brands

In 2026 spectup acted for the buyer on a contract manufacturer in DACH, an add-on for an existing platform, sourced off-market against the sponsor's written thesis. The owner hadn't run a process and wasn't planning one.

How add-ons are financed: delayed draw debt, rollover and earn-outs

In the example, $36M to $51M of add-ons has to be funded on top of a $100M platform, and each one has to fit the combined group's debt covenants before it closes. Five sources do most of the work:

• Delayed draw term loan. A delayed draw term loan is acquisition debt committed when the platform is financed and drawn only when an add-on closes; Proskauer's guide to delayed draw term loans notes that borrowers value a committed facility with set pricing for anticipated acquisitions.

• Incremental debt. Additional borrowing under the existing credit agreement, sized against the group's earnings once the add-on is in.

• Fund equity. Reserves the sponsor set aside at the platform investment, called as each add-on closes.

• Rollover equity. The selling owner reinvests part of the proceeds in the platform; Goodwin's March 2025 note for management teams cites its internal rollover survey: most PE-backed buyers require some form of rollover, and owner-managers often roll 10 to 50% of their equity.

• Seller notes and earn-outs. Part of the price is paid over time, or paid only if the add-on hits agreed targets after closing.

Lenders set debt limits for the combined group, so one expensive add-on can use up headroom the next three needed. The add-on price in the example matters twice: once in the return and once in the covenants.

When does a roll-up draw antitrust scrutiny in the US?

In the US, most add-ons are too small to be notified to the agencies one by one, which is why serial buying is easy to underestimate.

For 2026, the Hart-Scott-Rodino size-of-transaction threshold is $133.9 million, set out in the Federal Register notice of January 2026, and most add-on acquisitions sit well below it. Guideline 8 of the 2023 Merger Guidelines lets the agencies look at a pattern or strategy of multiple acquisitions in the same or related business lines and evaluate serial acquisitions collectively.

A roll-up strategy concentrated in one regional market is the profile that guideline addresses most directly. Bring antitrust counsel in when the programme is planned, before the regional share builds; this is general information, not legal advice.

Diligence and integration on a small target

A small add-on acquisition gets less diligence than a platform, but the risks that sink one sit in a few places:

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A common integration sequence is a 100-day plan: finance consolidation and reporting first, purchasing and systems next, brand changes last, because brands are where customers notice. Every customer an add-on loses takes its margin out of the $17M combined EBITDA in the example, multiplied by the exit multiple.

spectup manages buy-side diligence as a process; financial, legal and tax diligence, quality of earnings included, is done by the client's own advisors. The transaction runs to signing and then hands over, because integration is an operating job that belongs with the platform's own team.

Selling to a platform: what the add-on owner should know

An owner approached by a PE-backed platform is selling into a buy-and-build strategy, and three terms make that sale different from a sale to a trade buyer.

Rollover is part of the price, valued on a business the owner no longer controls and paid out on the sponsor's timetable.

• Rollover equity. Its value depends on the platform's debt, its performance and the exit multiple, so ask for the capital structure before agreeing the split between cash and equity.

• Earn-outs. Part of the price depends on results after closing, when the owner no longer controls pricing, staffing or reporting. The definitions, the accounting rules and the dispute mechanism deserve the same scrutiny as the headline number.

• The transition role. Most platforms ask the owner to stay for a period, often tied to the earn-out, so the role, reporting line and authority belong in writing before signing.

The second bite, the payout on rolled equity, arrives when the sponsor exits. A sponsor late in its hold may sell the platform, or move it into a continuation fund through one of the GP-led deals in private equity secondaries, and either route moves that date.

An owner with several approaches doesn't have to negotiate with one buyer at a time; a sell-side process puts them on one timetable and lets their offers compete.

Which add-on programmes destroy the multiple

I'd expect four kinds of programme to return no better than Bain's 1.4x arbitrage-only average, and often worse. Each one fails on price, people, pace or the exit market, whatever the sector.

The first buys at auction prices. When every add-on comes out of someone else's sale process, the platform pays the 8.5x row of the example and the arbitrage is gone before integration starts. In a live process our work moves from finding to not overpaying, with a walk-away number agreed with the client in advance.

The second buys owner-dependent revenue. A bolt-on acquisition whose customers buy from the owner rather than the business is worth less the day the owner steps back, and an earn-out only delays that discovery.

The third acquires faster than finance can consolidate. A company still outside the group's reporting uses lender headroom before it adds any, and an exit buyer discounts earnings it can't trace through one set of numbers.

The fourth relies on the exit multiple rising. Bain's March 2024 report put the cost of financing at about double what investors were modelling in 2020, so a plan that needs multiple expansion to cover its debt is a bet on the market.

How spectup runs an add-on search for a platform

spectup is mandated by the acquirer and paid by that side only: the sponsor or its platform, never the seller. We scope a buy-and-build run against one thesis as one programme; how long each search takes depends on how deep the universe is and how many owners are ready to talk.

1. Thesis. The sponsor's thesis becomes written acquisition criteria.

2. Universe. Built against the criteria, with a reason per name.

3. Shortlist. Screened on ownership as well as financials, ranked and signed off by the client.

4. Approach. Owners called directly by spectup, in the client's name or on a no-names basis as the mandate specifies; every answer is logged with its reason; a no is closed, and no name is approached twice on one thesis.

5. Qualification. Interested owners are taken to a letter of intent (LOI, the non-binding offer that opens exclusivity).

6. Diligence. Managed as a process, with the client's own advisors on the financial, legal and tax work.

7. Signing. Terms agreed through to signing, then a clean handover to the platform's team.

Fees are a monthly retainer plus a transaction fee that is capped in the mandate before any work starts and falls due when the transaction closes. How success fees on M&A mandates are usually calculated is set out in our piece on the Lehman formula and success fees.

What to test before committing to an add-on programme

Four tests can be run this quarter, before the platform is bought or before the next add-on acquisition is approved:

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If auction prices and an exit one turn lower together leave almost nothing, as in the last row of the example, don't start a buy-and-build strategy on arbitrage. Start it on a plan for growth and margin, the 2.2x side of Bain's data.

Then bring the thesis to a 30-minute call with spectup, and we'll tell you whether the universe behind it holds the twenty credible targets a search needs.