Exploring Clean Harbors, Inc. (CLH) Investor Profile: Who’s Buying and Why?

You're looking at Clean Harbors, Inc. (CLH) and wondering who's driving the stock's action right now, and honestly, it's the big money: institutions own a staggering 88.57% of the company, with giants like Wellington Management Group LLP holding over 10.43% of shares, so you have to understand their playbook. Are they buying for the long-term tailwind of environmental regulation, or is it a short-term bet on operational efficiency? The financial picture for 2025 is defintely mixed, showing a full-year Adjusted Free Cash Flow guidance midpoint of $475 million-a solid 30%-plus growth over last year-but the Safety-Kleen segment is still feeling the heat from soft base oil markets. The core investment thesis hangs on the Environmental Services segment, where demand for disposal is so strong that incineration utilization is running at 92% and new regulatory drivers like PFAS remediation are projected to pull in $100 million to $120 million in revenue this year alone. But, to be fair, the stock trades at a premium, and you have to ask: is the long-term growth from new capacity and environmental mandates already priced in, or is this just the start of a multi-year regulatory-driven rally?

Who Invests in Clean Harbors, Inc. (CLH) and Why?

If you're looking at Clean Harbors, Inc. (CLH), the first thing to understand is that the stock is overwhelmingly held by large, professional money managers. The investor profile is dominated by institutional players who see the company as a core holding in the essential environmental services sector, not a quick trade.

As of late 2025, institutional investors-think mutual funds, pension funds, and endowments-own about 88.57% of the outstanding shares. That's a massive concentration. Retail investors, the 'you' and 'me' on Main Street, hold a small fraction, around 2.97%, with the rest held by company insiders, including the founder. This high institutional ownership is a sign of confidence in the long-term business model. It's defintely not a stock driven by daily retail speculation.

The top holders are the giants you'd expect: Wellington Management Group LLP, Vanguard Group Inc., and BlackRock, Inc. These firms hold millions of shares, often for passive index funds or large, diversified portfolios. For example, Vanguard Group Inc. holds over 4.5 million shares, and BlackRock, Inc. holds over 4.5 million shares, according to recent 2025 filings. You can see how this all fits together, from the company's roots to its current structure, by looking at Clean Harbors, Inc. (CLH): History, Ownership, Mission, How It Works & Makes Money.

Here's a quick breakdown of the ownership structure:

• Institutional Investors: ~88.57%
• Insiders: ~8.46% (Alan S. McKim is the largest individual shareholder)
• Retail/Public: ~2.97%

The Core Investment Motivations: Growth and Moats

Investors are drawn to Clean Harbors, Inc. for two simple reasons: its market position-a deep economic moat (a structural business advantage that protects long-term profits)-and its clear growth trajectory, especially in high-margin services. The company is the leading North American provider of environmental and industrial services, a capital-intensive business with high barriers to entry due to specialized infrastructure and tough regulatory hurdles. It's hard for a new competitor to just show up.

The 2025 fiscal year results clearly show the drivers. Management revised its full-year 2025 Adjusted EBITDA guidance to a midpoint of $1.165 billion, representing 4% year-over-year growth. That's solid, but the real story is the cash flow. They raised the full-year adjusted free cash flow (FCF) guidance to a midpoint of $475 million, which is more than 30% growth from the prior year. Strong cash flow gives the company options, like reinvesting or paying down debt.

Specific growth catalysts also attract investors, particularly in the Environmental Services (ES) segment:

• Hazardous Waste Disposal Demand: Incineration utilization was high, hitting around 92% in the third quarter of 2025. High utilization means pricing power.
• PFAS Remediation: Work related to Per- and Polyfluoroalkyl Substances (PFAS) is a major tailwind, expected to generate between $100 million and $120 million in revenue for 2025.
• Strategic Investment: The company is investing $210 million in a new SDA Unit, a long-term capital commitment that signals confidence in future waste volumes.

Strategies: Long-Term Growth and Value

The investment strategies seen here are mostly long-term holding and a growth-at-a-reasonable-price (GARP) approach. When over 88% of the stock is in institutional hands, you aren't looking at short-term trading; you're looking at patient capital.

Value investors are attracted by the company's strong free cash flow and its essential, non-cyclical nature, which provides a defensive quality to a portfolio. Growth investors focus on the expanding margins in the ES segment and the high-growth, high-barrier-to-entry business of hazardous waste disposal. The stock's valuation, with an enterprise value-to-EBITDA (EV/EBITDA) multiple of about 8.63, suggests the market is pricing in continued, moderate growth, not a speculative boom.

For most institutional holders, Clean Harbors, Inc. is a core infrastructure play, a way to gain exposure to tightening environmental regulations and the growing need for complex waste management. Analysts have a consensus 'Moderate Buy' rating, with an average 12-month price target of approximately $254.58, indicating a belief in steady, predictable upside.

What this estimate hides is the potential impact of a severe economic downturn, which could slow down industrial services demand, but the hazardous waste side remains resilient. Still, the current high FCF generation gives the company a cushion to weather any near-term economic choppiness.

Next step: Review your portfolio's exposure to environmental services and see if a steady cash-flow generator like Clean Harbors, Inc. fits your long-term infrastructure allocation strategy.

Institutional Ownership and Major Shareholders of Clean Harbors, Inc. (CLH)

You're looking at Clean Harbors, Inc. (CLH), and the first thing to understand is that it's an institutionally-dominated stock. This isn't a retail-driven play; it's a core holding for some of the biggest money managers globally. The direct takeaway is that institutional investors own a massive chunk-about 90.43% of the company's stock-which means their collective decisions drive the stock price and often influence strategy.

When institutions hold this much of a company, you get stability, but you also get less volatility from individual investor sentiment. It's a double-edged sword, but for a specialized environmental services company like Clean Harbors, it signals strong conviction in the long-term regulatory and market tailwinds.

The Heavy Hitters: Top Institutional Investors in CLH

The investor profile for Clean Harbors, Inc. is a who's-who of asset management giants. These firms aren't just buying a few shares; they are making multi-billion dollar bets on the environmental services sector. As of the third quarter of 2025 (Q3 2025), the top three institutional holders alone control a significant portion of the outstanding shares.

Here's a snapshot of the largest institutional stakes, based on the most recent 13F filings for Q3 2025. This shows you exactly who has the most skin in the game.

Notice BlackRock, Inc. is right up there. My two decades in this business, including time as an analyst head, tell me that when firms like this commit capital, they've done the deep work on the regulatory and competitive landscape. They are not chasing a quick trade; they are buying the long-term infrastructure story.

Recent Shifts: Institutional Buying vs. Selling

The buying and selling activity over the last year shows a net accumulation. Honestly, that's the most important signal. In the last 12 months leading up to Q3 2025, institutional investors purchased a total of approximately 13.16 million shares, representing about $2.90 billion in transactions, while selling approximately $1.89 billion.

However, the quarterly picture is mixed, which is normal for a highly-owned stock. In Q3 2025, there were 288 institutional positions that decreased and 244 that increased. For example, some top holders like Wellington Management Group LLP and Vanguard Group Inc. slightly trimmed their positions by 3.311% and a smaller percentage, respectively, in Q3 2025. Still, you saw significant accumulation from others. D1 Capital Partners L.P., for instance, boosted its stake by over 1 million shares in Q3 2025.

This tells me that while some large funds are taking profits after a strong run, others are stepping in to establish or significantly build their positions, viewing any dip as a buying opportunity. The net inflow suggests the conviction remains strong. You can read more about the underlying financials in Breaking Down Clean Harbors, Inc. (CLH) Financial Health: Key Insights for Investors.

The Impact of Institutional Conviction on Strategy

These large investors are not passive. Their immense holdings give them a powerful voice in the company's direction, especially regarding capital allocation (how the company spends its money) and strategic focus. Clean Harbors, Inc. is currently benefiting from a clear investment narrative that aligns perfectly with institutional mandates.

The primary driver is the growing urgency and evolving regulatory landscape around PFAS (Per- and Polyfluoroalkyl Substances) and hazardous waste management. This is a multi-billion-dollar opportunity. Clean Harbors, Inc. is uniquely positioned as the only company with end-to-end PFAS destruction capabilities, which is a major near-term catalyst for revenue and margin growth.

• Validate Strategy: Institutional buying validates management's focus on high-margin, regulatory-driven services, like PFAS destruction.
• Support Capital Allocation: Their support backs the company's emphasis on ongoing share buybacks and disciplined mergers and acquisitions (M&A) activity, signaling a focus on shareholder returns.
• Buffer Volatility: The high institutional ownership acts as a buffer, reducing the stock's vulnerability to panic selling from retail investors.

The risk is always execution. If the company missteps on integrating its acquisitions or if the regulatory timelines for PFAS are defintely delayed, these large holders can become sellers quickly. But for now, their money is betting on the regulatory tailwinds and the company's unique infrastructure.

Next Step: You should track the next round of 13F filings (Q4 2025) to see if the recent buying momentum from funds like D1 Capital Partners L.P. continues, which would signal a new wave of institutional conviction.

Key Investors and Their Impact on Clean Harbors, Inc. (CLH)

If you're looking at Clean Harbors, Inc. (CLH), the immediate takeaway is that this is a company overwhelmingly owned by professional money managers. Institutional investors hold approximately 90.43% of the company's stock, totaling an immense value of around $10.334 billion as of November 2025. This high concentration means their collective sentiment-their buying and selling-is what truly drives the stock price, not the individual retail investor.

The investor profile here is less about a single activist shareholder demanding a shake-up and more about large, long-term asset managers who view CLH as a critical, essential-service infrastructure play. The business of hazardous waste management and environmental services is sticky, and these funds are betting on that stability and the company's strong market position.

The Big Three: Passive Giants and Their Holdings

The top shareholders are the usual suspects in the institutional world, primarily passive index funds and massive asset managers. These firms are not typically looking for a boardroom fight; they are buying the market, and CLH is a large component of the indices they track.

Here's the quick math on the top three as of the third quarter of 2025:

• Wellington Management Group LLP: Held 5,574,152 shares.
• Vanguard Group Inc: Held 4,552,397 shares.
• BlackRock, Inc.: Held 4,534,653 shares.

What this tells you is that the stock's stability is tied to the long-term capital allocation strategies of these behemoths. Their sheer size means their quarterly adjustments, even small ones, can move the needle.

Recent Moves: A Mix of Trimming and Aggressive Buying

Looking at the most recent 13F filings from the end of the third quarter of 2025, we see a subtle divergence in strategy among the largest holders. While the passive giants slightly trimmed their positions, a few active managers saw a compelling opportunity to build up their stakes.

The three largest holders-Wellington Management Group LLP, Vanguard Group Inc, and BlackRock, Inc.-all slightly reduced their positions. Wellington, the largest holder, decreased its stake by 3.311%, selling 190,853 shares. Vanguard and BlackRock also saw minor reductions of 30,868 and 10,831 shares, respectively. This is often routine rebalancing, not a signal of lost confidence.

The more interesting action came from the hedge fund side. For example, D1 Capital Partners L.P. significantly increased its stake, buying an additional 1,001,946 shares to bring its total holding to 2,445,583 shares. Also, William Blair Investment Management LLC acquired a new, substantial stake in the second quarter of 2025, valued at approximately $95,115,000. These active moves suggest a strong conviction in the company's valuation, especially after the company missed its quarterly earnings per share (EPS) estimate of $2.37, reporting $2.21 instead.

Here is a snapshot of the notable Q3 2025 activity:

The Nature of Investor Influence: Quiet Conviction

Since the ownership is largely passive (Schedule 13G filings, which indicate a passive stake over 5%, are common here), the influence on Clean Harbors, Inc.'s day-to-day decisions is subtle. It's not the kind of activist pressure that forces a CEO change or a major divestiture. Instead, the influence is felt through the capital markets.

When a major fund like Wellington Management Group LLP or BlackRock, Inc. makes a large trade, it signals to the rest of the market whether the company is executing on its long-term strategy. The fact that institutional investors own nearly all the stock means management is constantly accountable to these large, sophisticated holders at investor conferences, like the one Clean Harbors attended in March 2025, where they highlighted their strategic growth drivers. This is a business built on essential service and scarce assets, so the focus for investors is on capital deployment, margin expansion-like the 100 basis point increase in adjusted EBITDA margin to 20.7% in Q3 2025-and strategic tuck-in acquisitions.

You can learn more about the foundation of this company's business model and ownership history at Clean Harbors, Inc. (CLH): History, Ownership, Mission, How It Works & Makes Money. The next step for you is to cross-reference D1 Capital's increased conviction with the company's recent announcement of a $210 million investment in its SDA (Stabilization and Disposal Area) unit and its raised full-year adjusted free cash flow guidance to a midpoint of $475 million for 2025. That's where the smart money is putting its focus.

Market Impact and Investor Sentiment

You're looking at Clean Harbors, Inc. (CLH) right now, and the investor profile tells a story of long-term institutional conviction mixed with near-term market realism. The direct takeaway is that major shareholders hold a Moderate Buy consensus, largely betting on the company's unique, high-barrier-to-entry assets despite a recent earnings hiccup. Institutional investors own a massive 90.43% of the stock, so their sentiment is the only one that truly matters here.

Honestly, the market sentiment is positive but cautious. The stock is trading at a premium price-to-earnings (P/E) ratio of 28.8x, which is higher than the industry average of 21.8x. That premium suggests investors are pricing in future growth, but it also makes the stock sensitive to any bad news. Still, the short interest is low-just about 1.4% of the float-so there isn't a lot of bearish pressure building up.

Who's Buying and Why: The Institutional Conviction

The investor base for Clean Harbors, Inc. is dominated by the heavy hitters. Firms like Wellington Management Group LLP, Vanguard Group Inc., and Blackrock Inc. hold substantial positions, signaling a belief in the company's long-term moat-its disposal and incineration network. Blackrock Inc. alone holds about 8.49% of the company's shares.

Here's the quick math on institutional money: over the last 12 months, institutional inflows totaled about $2.90 billion, significantly outpacing the $1.89 billion in outflows. This net buying activity confirms that the biggest players are adding to their positions, seeing the recent price drops as buying opportunities. They are focusing on the company's core strength: its Environmental Services (ES) segment, which continues to show robust demand for waste disposal and recycling assets.

• Wellington Management Group LLP: Top institutional holder.
• Vanguard Group Inc.: Holds 8.52% of shares.
• Blackrock Inc.: Controls 8.49% of the company.

Recent Market Reactions and Analyst Perspectives

The stock market defintely reacted sharply to the Q3 2025 earnings report. Clean Harbors, Inc. reported earnings per share (EPS) of $2.21, missing the consensus estimate of $2.37. Revenue of $1.55 billion also fell short of the $1.58 billion expectation. This miss led to a sharp, negative market reaction, but the stock's 1-day return of 3.74% shortly after suggested a quick stabilization of investor confidence.

Analysts are mostly shrugging off the short-term macro-economic softness, which primarily hit the Industrial Services segment. They see the future value tied to the company's unique position in managing emerging contaminants like per- and polyfluoroalkyl substances (PFAS). The consensus price target sits around $254.58, implying a potential upside of over 20% from current levels.

The company itself is confident, raising its full-year 2025 Adjusted Free Cash Flow guidance to a range of $455 million to $495 million, up from a prior midpoint of $460 million, which shows strong cash generation despite the revenue miss. The revised full-year 2025 Adjusted EBITDA guidance is now between $1.155 billion and $1.175 billion.

What this estimate hides is the risk from chemical and refining customers continuing to limit their turnaround spending, which impacts the Industrial Services business. But the core environmental disposal business is a rock. If you want to dive deeper into the fundamentals, you can check out Breaking Down Clean Harbors, Inc. (CLH) Financial Health: Key Insights for Investors.

Next step: Review your portfolio's current allocation to the environmental services sector to ensure you're positioned to benefit from the long-term regulatory tailwinds Clean Harbors, Inc. is uniquely positioned to capture.