Harvest Partners Buys Integra Testing Services From Keystone Capital: Inside a Sponsor-to-Sponsor Deal

Harvest Partners, LP announced on July 1, 2026 that it has acquired Integra Testing Services, a national provider of commercial HVAC testing, balancing, and controlled-environment compliance services, from Keystone Capital Management, LP. Terms of the deal were not disclosed, but the mechanics are laid out in the companies' own release, carried by PR Newswire. This is a sponsor-to-sponsor transaction: one private equity firm selling a portfolio company to another private equity firm, with no strategic acquirer and no public listing anywhere in the chain. If you invest in private markets, or you're weighing whether to, this deal is a clean, current example of how that structure actually works, and what it does and doesn't tell you about the health of an asset.

What actually happened: the deal mechanics

Keystone Capital Management built Integra from scratch, in PE terms. Starting in 2021, Keystone combined two platforms, Fulton and Associates and Neudorfer Engineers, and then bolted on roughly 20 add-on acquisitions over five years to create a national testing, adjusting, and balancing (TAB) and commissioning business. That term, TAB, describes the regulated process of verifying that a building's heating, ventilation, and air conditioning systems actually perform to design specification and code. It's not glamorous work. It's also mandatory in most commercial construction, which is exactly why PE firms like it.

The result of that five-year build-out: Integra now runs more than 600 professionals out of 30 offices across the United States, Mexico, and Guam, serving life sciences companies, hospitals, universities, government facilities, and data centers, according to reporting from citybiz. Harvest Partners is buying that platform to fold into what it's calling a mission-critical infrastructure services strategy. Harvest is not a small shop. Founded in 1981, the firm manages more than $20 billion in assets as of March 31, 2026, according to Harvest Partners' own disclosures, and its flagship Fund IX closed in 2023 at $5.34 billion. It has made 98 platform investments across nine funds since inception. Keystone, the seller, is smaller but not new to this game either: founded in 1994, it manages more than $1 billion across two funds and has completed more than 200 acquisitions historically, spanning more than 50 platform companies, per its own firm history.

Two names carry over from the old ownership to the new one: CEO Dominic Mazzolini and Shane McHugh are staying on and rolling equity into the Harvest-backed structure, a detail confirmed in a Morningstar mirror of the release. That's worth flagging before we go further, because management rollover is one of the few hard signals retail-adjacent investors get in a deal like this, and I'll come back to why it matters.

The advisory list is long enough to tell you this deal had real process behind it. Harris Williams and Robert W. Baird worked the sale side alongside Solomon Partners and Jefferies in various capital markets and advisory roles, Houlihan Lokey appears in the financing structure, and DLA Piper and Kirkland & Ellis handled legal work for the respective parties. Michael DeFlorio and Campbell MacColl are named as Harvest deal principals in the release. That's a lot of billable hours for an "undisclosed terms" transaction, which itself is normal. Sponsor-to-sponsor deals rarely publish price or multiple, because neither side wants the number benchmarked publicly for their next deal.

Why this is a sponsor-to-sponsor deal, and what that signals

A sponsor-to-sponsor deal, sometimes called a secondary buyout, is exactly what it sounds like: one financial sponsor sells a portfolio company directly to another financial sponsor, instead of to a strategic buyer (an operating company in the same industry) or via an IPO. No public market touches the asset at any point. The company simply moves from one PE balance sheet to another.

This matters for three reasons if you're trying to read the tea leaves on private equity right now.

First, it's a statement about where each fund sits in its own life cycle. Keystone launched the Fulton and Neudorfer combination in 2021. Five years is a standard hold period for a platform build, and PE funds have a defined lifespan, typically 10 years, with capital committed for the first five and harvested over the back half. Keystone needed to return capital to its limited partners (the pension funds, endowments, and family offices that fund PE vehicles), and a sale, any sale, accomplishes that. Harvest, on the other hand, closed Fund IX at $5.34 billion in 2023 and needs to deploy that capital into platforms before its own investment period closes. The timing lines up on both sides for reasons that have nothing to do with a strategic acquirer showing up with a check.

Second, secondary buyouts are a pricing signal, and not always a flattering one. When a strategic buyer, say a large engineering or facilities-services conglomerate, acquires a company, it can often pay a premium because it captures synergies: shared back-office costs, cross-selling, purchasing power. A financial sponsor buying from another financial sponsor generally can't claim those synergies in the same way. It's paying for growth and margin expansion on a standalone basis, financed with a fresh layer of debt. According to PwC's midyear 2026 deals outlook, overall PE deal volume in the first half of 2026 was down roughly 34% year-over-year even as average deal size rose about 4x, meaning fewer deals are getting done, but the ones that close are bigger and better-vetted. That backdrop tells you the exit market for smaller and mid-sized platforms remains constrained. Firms selling to other firms, rather than to a strategic acquirer or through an IPO, is often what happens when the more obvious buyers aren't showing up.

Third, and this is the part I'd underline for anyone doing diligence on a PE-adjacent fund or feeder vehicle: sponsor-to-sponsor deals face more valuation scrutiny than they used to, precisely because they don't have an independent, arm's-length strategic buyer setting the price through competitive tension with an operator's own P&L logic. Two financial buyers pricing off similar models, similar leverage assumptions, and often the same universe of lenders can produce valuations that look more like an internal transfer than a market clearing price. That's not an accusation against this specific deal. It's a structural reason to ask, every time you see one of these headlines, who's advising on fairness and what multiple actually got paid.

Why this matters if you're watching PE roll-up strategies from the sidelines

I want to be specific about why a mid-market HVAC compliance testing deal deserves attention if you don't work in facilities engineering and never plan to.

Integra is a roll-up in a regulation-driven, recurring-revenue niche. Buildings don't get to skip HVAC testing and commissioning. Life sciences facilities, hospitals, and data centers in particular need continuous, documented compliance, because a failed clean-room air-balance test isn't a paperwork problem, it's a shutdown problem. That makes the underlying demand relatively insulated from the ordinary business cycle compared to, say, discretionary consumer services. It's exactly the kind of "boring but essential" services category that PE has been rolling up aggressively for the past decade, the same playbook applied to veterinary clinics, dental service organizations, and environmental testing labs.

What Keystone did with Integra, combine fragmented regional players (Fulton and Associates, Neudorfer Engineers, roughly 20 add-ons) into a national platform with standardized reporting and cross-sell across service lines, is the textbook roll-up thesis. The bet is that a fragmented, mom-and-pop-heavy industry has consolidation economics: buy small firms at 4-6x EBITDA, combine them, sell the platform at a higher multiple because scale and national coverage command a premium. When it works, both the original sponsor and its limited partners do well. When Harvest buys that platform now, it's underwriting the belief that there's a second leg of that multiple expansion left to capture, probably by adding more mission-critical infrastructure services around the existing base, and possibly by continuing the same acquire-and-integrate model Keystone ran.

If you're an accredited investor with exposure to a PE fund, a fund-of-funds, or a feeder vehicle marketed toward high-net-worth allocators, deals like this are the machinery underneath your quarterly capital account statement. You're rarely told the entry multiple, the leverage ratio, or the specific EBITDA the deal was priced against. Watching disclosed, comparable transactions like this one is one of the few free windows into how that machinery is actually pricing risk in mid-2026, especially with deal volume down and dry powder (committed but undeployed capital) piling up across the industry.

The management rollover detail is worth weighing on its own. Mazzolini and McHugh kept skin in the game across two consecutive ownership changes. That's a reasonable proxy for operator conviction, the people who know the business best are choosing to keep equity rather than cash out entirely. It is not proof of anything. Executives roll equity for retention-package reasons, tax reasons, and because a new sponsor sometimes requires it as a condition of the deal, not purely because they're bullish. Read it as a data point, not a guarantee. For more on how AIN thinks about evaluating sponsor economics and alignment across deal structures, see AIN's private equity coverage.

What could go wrong here: the risks worth naming

Be explicit about the downside case, because deal press releases never will be.

Leverage risk is the first one. Sponsor-to-sponsor deals are typically financed with a new layer of acquisition debt on top of whatever debt Integra already carried under Keystone. If interest rates stay elevated through 2026 and 2027, debt service eats into the cash flow that would otherwise fund further acquisitions or distributions. A roll-up built on serial small acquisitions is particularly exposed here, since each add-on typically carries its own financing and integration cost.

Integration risk is the second. Twenty-plus add-on acquisitions across five years is a lot of different company cultures, software systems, and client relationships to fold into one operating platform. Roll-ups fail more often from integration friction, duplicate systems, client attrition after a founder-owner exits, key technician turnover, than from any flaw in the original market thesis. Harvest is inheriting whatever integration debt Keystone left behind, visible or not.

Regulatory concentration is the third, and it cuts both ways. Integra's revenue exists because building codes and life-safety regulations require ongoing HVAC testing and certification. That's a durable tailwind, but it also means the business is exposed to any material change in code enforcement, inspection frequency, or the compliance standards themselves at the state or federal level. A relaxation of commissioning requirements in any major jurisdiction, however unlikely, would directly hit demand. If you want a primer on how regulatory frameworks shape recurring-revenue services businesses like this one, regulatory compliance guides is a useful place to start.

Liquidity risk is the fourth, and it's the one I'd stress hardest for individual investors. This entire transaction closed without a single public market checkpoint. No IPO, no public strategic acquirer, no market-clearing price discovery event that outside investors can observe. If you hold an interest in a fund that owns something like Integra, your liquidity is entirely dependent on the fund manager finding another buyer, financial or strategic, on a timeline that isn't yours to control. The SEC's own investor alerts on private funds flag this exact illiquidity risk as a standing concern for anyone allocating to closed-end vehicles. The PwC data point on deal volume being down 34% year-over-year is the macro version of that same risk: fewer buyers are transacting right now, and that constrains how quickly any single position can be exited at a fair price.

Finally, undisclosed terms cut against you as an outside observer. Neither Harvest nor Keystone disclosed the purchase price or the EBITDA multiple paid. That's standard practice, not a red flag by itself, but it means anyone trying to independently verify whether this was a fair transaction for Keystone's limited partners, or a fair entry price for Harvest's, is working without the one number that would settle the question.

What to watch next

A few concrete things to track from here. Watch whether Harvest announces additional bolt-on acquisitions onto the Integra platform within the next 12 to 18 months. That would confirm the roll-up thesis is continuing rather than this being a one-and-done platform absorption. Watch Keystone's next fundraise. A firm that just generated a realized exit has a story to tell limited partners, and how quickly it closes a new fund tells you how the market received this deal's economics. And watch the broader HVAC compliance and mission-critical infrastructure services space for competing consolidators; if other PE firms accelerate roll-ups in adjacent niches, testing, balancing, commissioning, environmental monitoring, that confirms institutional capital sees more room to run in these unglamorous, regulation-anchored service categories.

None of that requires you to have a position in Harvest Partners, Keystone Capital, or Integra Testing Services. It just requires paying attention to how capital is moving through the parts of the economy that keep buildings running, tested, and compliant, one HVAC balancing report at a time.

Author Disclosure: Jeff Barnes, MBA has no personal position in any company, fund, or platform named in this article. Angel Investors Network has no current commercial relationship with any party mentioned. AIN provides marketing and education services, not investment advice. Past performance does not guarantee future results. All investments involve risk, including loss of principal.