Onterris (Montrose Environmental) Acquisitions: What It Buys and How It Pays

Onterris, the listed environmental services group called Montrose Environmental until April 2026, has bought more environmental testing and consulting firms in the US since 2015 than any other buyer in our data. It says it has made more than 70 acquisitions since it was founded in 2012. Since 2015 we count 54 that are testing, inspection and certification (TIC) firms, all but two of them air emissions testing firms, environmental laboratories i environmental lub health and safety consultancies.

Onterris has never published the multiple it paid for a firm. Our analizie wycen TIC puts the median for TIC deals under $50M at 8.0x EBITDA (21 deals). Onterris’s chief executive told investors on its third-quarter earnings call in November 2025 that smaller private firms sell for mid to high single digits, which puts our median near the top of his range. In our judgment a listed buyer that promises its shareholders disciplined prices pays toward the bottom of it.

About three quarters of what Onterris paid for the businesses it bought in 2024 came in cash at closing. The rest came as earn-outs, paid later if revenue or earnings targets are met, and as Onterris shares. Part of a seller’s price therefore rides on how the firm does inside the group and on the share price. Since August 2026, Onterris’s own board has also been reviewing options that include a sale of Onterris itself.

Onterris Companies and Brands: CTEH, Enthalpy Analytical and Epic Environmental

In April 2026 the group brought its brands together under the one Onterris name. Until then it traded as Montrose Environmental, and four businesses it had bought kept their own names. CTEH, the largest acquisition the group has made, was one; the others were the Enthalpy Analytical laboratories, ECT2 in water treatment technology and Epic Environmental in Australia. The legal name changed on 17 April, and the shares have traded as ONT, in place of MEG, since 4 May. With its first-quarter results on 6 May, the company said one brand would help it sell more of its services to each client, bring its teams closer and keep its staff busier.

Based in North Little Rock, Arkansas, the group was founded in 2012 and listed on the New York Stock Exchange in July 2020. It had revenue of $830.5M in 2025 and about 3,500 staff, three quarters of them in the US. Since selling its Danish business at the end of 2025 it has worked only in the US, Canada and Australia.

In 2026 it began reporting two segments instead of three. Testing crews and laboratories belong to Measurement and Analysis, consultancies and treatment work to Consulting and Treatment. A firm Onterris buys is run as a service line in one or the other.

How Many Companies Onterris Acquires, and What Size

By our count Onterris has bought 45 environmental testing and consulting firms in the US, against 40 for Alliance Technical Group and 24 for Pace Analytical, all since 2015. Across its three countries it has made 54 TIC acquisitions.

Its busiest year was 2015, five years before it listed. After that it bought between two and seven firms a year until September 2024. It bought nothing in 2025 and came back with two firms in October and November 2026.

Onterris’s annual reports give what it paid each year for every business it bought, TIC or not, with cash, shares and earn-outs added together. From 2018 to 2024 it paid $751.5M for 39 businesses, about $19M each, or about $13M each leaving out CTEH. The average price per business rose from about $8M in 2018 to about $26M in 2024. Only 2020 was higher, the year it paid $243M for CTEH. In 2024 it paid under $50M for each of its six purchases.

The restart has been smaller still: two firms and one smaller purchase, $13.9M of funding in all, by its results release of 4 November 2026.

What Onterris Buys and Where

From 2015 to 2019, 22 of the 30 firms Onterris bought were testing firms. Since 2020, 15 of 24 have been consultancies.

Testing firms are still on its list. One of the two it added in 2026 is a laboratory.

Outside the US Onterris has bought five firms in Canada and two in Australia. Its other 47 TIC deals were in the US, the 45 environmental testing and consulting firms plus the tobacco testing laboratory and the software firm. The US brought in $678.4M of its $830.5M revenue in 2025. An owner in Canada or Australia is dealing with a buyer still building its presence there.

What Onterris Pays: Acquisition Multiples

Buyers price a TIC firm as a multiple of its EBITDA (earnings before interest, tax, depreciation and amortization), adjusted for one-off costs and the owner’s own pay. At 6x, a firm with $2M of EBITDA has an enterprise value (EV) of $12M. That is the value of the whole business; the owner repays any debt out of it and keeps the rest.

Onterris’s annual reports give a total price for each year’s purchases but no earnings figure for the businesses before they were bought, so no multiple can be read from them.

With every 2024 purchase under $50M, the fair comparison is TIC deals of that size, which sold at a median of 8.0x EBITDA (21 deals). Bigger deals fetch more, which lifts the median for TIC deals of every size to 9.9x (54 deals).

Onterris’s chief executive, Vijay Manthripragada, gave the buyer’s view on its third-quarter earnings call on 5 November 2025. Speaking of EBITDA multiples, he said the smaller private assets “continue to trade in kind of that mid to high single digits”. Our 8.0x sits near the top of that range.

The company’s annual report for 2025 tells shareholders it buys at “disciplined valuation levels”. Its results release of 25 February 2026 said it would restart “smaller, bolt-on and highly accretive acquisitions” in 2026, subject to valuation, capital allocation and leverage. In our judgment a listed buyer keeps both promises by paying toward the bottom of the range.

On a hypothetical $2M of EBITDA, 5x gives $10M, 8x gives $16M and 9x gives $18M. From 5x to our 8.0x median is three years of the firm’s profit, and to 9x four. Where a seller lands depends on the firm and on whether other buyers are bidding for it.

How Onterris Structures a Deal

Of the $155.9M Onterris paid for six businesses in 2024, about three quarters was cash at closing, funded from cash on hand and its revolving credit facility.

Earn-outs made up 19% of the 2024 total, at the value Onterris put on them at closing. The share varies from year to year, from 1.5% of the price in 2023 to 19% in 2024, and came to 12.5% of everything paid from 2018 to 2024. Its annual reports say the targets are “revenue or earnings thresholds”, and since 2021 they have described every earn-out as capped. On three of the six deals of 2024, earn-outs made up between a fifth and nearly two fifths of the price. Onterris’s earn-outs have mostly been paid within one to three years of closing, and one about four years after.

Onterris shares accounted for 7% of the 2024 total, and as much as a fifth of the price on one deal. The group may also choose to pay part of an earn-out in shares. Of the $17.8M it paid sellers in earn-outs in 2025, $7.7M came as stock.

CTEH, the largest deal, shows what a full payout looks like. When Montrose bought the firm in April 2020 it paid $175.0M in cash and $25.0M in shares at closing. It valued the two earn-out stages at about $45M, and with other adjustments the total came to $243.1M. The stages were tied to CTEH’s EBITDA for 2020 and 2021 and capped at $50.0M and $30.0M. Both were paid in full, $80.0M in all, about $35M more than the value put on them at closing.

Take a hypothetical firm sold for $20M on the 2024 mix. About $14.8M would come in cash at closing, about $3.8M as an earn-out valued at closing, and about $1.4M in Onterris shares. If the firm misses its targets the $3.8M shrinks, while a fall in the share price takes the $1.4M down with it. Against another buyer’s offer, compare the cash at closing first. Then judge what the rest is likely to become.

In the letter of intent, pin down how much of the price is paid at closing and what the earn-out targets are. Agree how revenue or EBITDA will be measured once your firm runs on the group’s systems, what the cap is, and whether Onterris may pay any of the earn-out in shares. A letter of intent usually brings exclusivity, and once Onterris is the only buyer at the table you have little left to bargain with.

Co dzieje się po zamknięciu transakcji

We would expect your firm’s name to go. The April 2026 rebrand took in firms the group had run under their own names for years.

The business itself is folded in as well. In its annual report for 2023 Onterris writes that “each business we acquire is systematically integrated into our systems and processes, thereby creating revenue synergy opportunities and operating leverage.” Your clients are offered the rest of the group’s services. In 2023, 51% of its revenue came from clients who used more than one of them, up from 35% a year earlier. Once your clients buy from the rest of the group, someone has to decide which revenue and costs count toward your earn-out targets.

A business Onterris buys can also be sold on. When the group left Europe at the end of 2025, it sold the Danish water treatment business it had bought two and a half years earlier, for cash and a minority stake in the buyer. Its former owners received an earn-out payment in 2025, the year it was sold on. If your earn-out is still running when your firm is sold on, the agreement needs to say who pays it and how the targets are then measured.

Onterris Competitors: Who Else Buys Firms Like Yours

Ten groups besides Onterris have bought seven or more environmental testing and consulting firms in the US, Canada and Australia since 2015. Which of them would compete for yours depends largely on where it is.

In the US, 136 buyers have made 370 such deals since 2015. After Onterris, most of the active ones are platforms owned by private equity, such as Alliance Technical Group, Pace Analytical, Verdantas and J.S. Held, while the listed Eurofins i SGS buy laboratories. Canada has had 29 buyers, with Onterris and Alliance Technical Group on five deals each and SLR Consulting on four. Australia has had 19, with SLR Consulting in front.

An owner who answers Onterris’s approach alone negotiates with one buyer, on the price and on how much of it is paid later. We run a competitive process among the strategic groups, private equity platforms and other buyers with a real reason to want your firm, so you choose between the best offers and get the best price, with as much of it as possible paid at closing.

Is This a Good Time to Sell to Onterris?

Onterris is buying again, so an approach now is a real one. It buys in small deals while it pays down debt. Its own board is also weighing a sale of the company, which could change who pays the later part of your price. Its pause in buying began with its third-quarter 2024 results, on 6 November 2024, when it said it would redeem the preferred stock held by Oaktree, its investor from before the listing, and reduce debt, “concurrently de-emphasizing acquisitions”.

Its chief executive said on the earnings call of 5 November 2025 that its acquisition strategy “is about capability and geographic reach”, and named Canada and Australia as places where it is growing. The firms it looks for, in the words of its annual reports, are “led by high quality scientists and management teams”.

Each deal now has to fit a plan to bring debt down from 2.9 times EBITDA at 30 September 2026 to about 2.5 times by the end of the year. “We expect to continue our acquisition strategy, while maintaining our leverage goals,” the company said on 4 November 2026.

The board’s review, announced on 5 August 2026, covers the business and its options, “including evaluating acquisition interest in the Company”. By 4 November Onterris had engaged with “a number of strategic and financial parties”. An earn-out agreed now may be measured inside a group with a new owner, and the value of any Onterris shares you take will be set by that sale or by the market.

Talk to us before you reply to Onterris, and before you put a figure in writing or sign a letter of intent. If keeping the company is the better choice for you, we say so. The first conversation is confidential. Our Doradztwo M&A dla spółek TIC wyjaśnia, jak pracujemy.

O Aventis Advisors

Doradzamy właścicielom przy sprzedaży firm o typowej enterprise value od 5 mln USD do 100 mln USD, jako partnerzy sieci Globalscope. Doradzamy też seryjnym nabywcom, dlatego wiemy, jak budują swoje oferty i gdzie zostawiają pole do negocjacji.

Ostatnie transakcje:

• Doradztwo dla Apave przy przejęciach ISOCERT i De Duurzame Adviseurs.
• Sprzedaż CKSource, twórcy edytora tekstu sformatowanego (rich-text), na rzecz PSG za pośrednictwem Tiugo Technologies, po globalnym procesie, w którym wpłynęło kilka listów intencyjnych.
• Doradztwo dla Visma przy przejęciu SaldeoSMART.

„Byliśmy pod wrażeniem umiejętności negocjacyjnych Marcina i zdolności Aventis do doprowadzania spraw do skutku.”

Sindre Talleraas Holen, dyrektor ds. M&A, Visma

„Aventis Advisors wzięło na siebie najcięższą pracę, dzięki czemu nasz zespół zarządzający mógł skupić się na prowadzeniu firmy.”

Wiktor Walc, prezes, CKSource

Napisz do nas na adres marcin.majewski@aventis-advisors.com. Pierwsza rozmowa jest poufna.

Metodologia

The count covers majority acquisitions of TIC firms by Onterris, then Montrose Environmental, or one of its companies, closed from 2015 to 14 November 2026. The deals come from our deal database, built from Mergermarket and public sources such as press releases, news and annual reports. Deals from 2018 on were checked against Onterris’s filings and releases. Deals from 2015 to 2017, before it listed, rest on Mergermarket, trade sources and its archived releases, seven of them on archived release titles only. What Onterris paid, in cash, shares and earn-outs, comes from its annual reports for 2018 to 2025 and its quarterly filings for 2026. Its chief executive’s words come from the transcript of the earnings call of 5 November 2025.

Our database holds 61 entries for the group, and we count 54. Two entries record a deal already counted, and five businesses sit outside TIC, such as remediation contractors and water treatment. The company’s figure of more than 70 starts in 2012 and includes businesses outside TIC, and our count finds fewer of the unannounced deals Montrose made while it was private. Its annual reports count every business bought, TIC or not, so their 39 for 2018 to 2024 is more than our 34. The table of competing buyers covers groups with seven or more acquisitions of environmental testing and consulting firms in the US, Canada and Australia since 2015, each under its owner today.

The TIC medians come from our TIC valuation research, 2,841 deals since 2015, and use enterprise value (equity value plus net debt). Deal size is enterprise value where disclosed, otherwise the disclosed deal value. Onterris reports in US dollars, and every figure here is in US dollars.