Exploring Pulmonx Corporation (LUNG) Investor Profile: Who’s Buying and Why?

You're looking at Pulmonx Corporation (LUNG) and wondering why the institutional money is still so heavily invested-over 91% of the stock is held by institutions-when the company is guiding for a 2025 full-year net loss and analysts are cutting price targets. Honestly, that's the million-dollar question in MedTech right now. We know the company is projecting full-year 2025 total revenue between $89 million and $90 million, with a strong gross margin of approximately 73%, which shows their core product, the Zephyr Valve, has solid unit economics. But, the Q3 2025 net loss of $14.0 million and operating expenses guided up to $126 million for the year tell a story of high cash burn to chase market share. So, who are the big players like Primecap Management Co. CA (holding over 4.9 million shares) and Blackrock, Inc. (with over 2.6 million shares) that are buying or holding, and what long-term regulatory or market catalysts are they seeing that the short-term earnings reports are hiding? Their conviction is defintely worth exploring.

Who Invests in Pulmonx Corporation (LUNG) and Why?

If you are looking at Pulmonx Corporation (LUNG), you are defintely looking at a medical technology growth story where the institutional money is already firmly in place, but recent performance has created a deep divergence in investor sentiment.

The core investment thesis hinges on the Zephyr Endobronchial Valve's position as a minimally invasive, FDA-approved breakthrough device for severe emphysema, a huge market. But the recent volatility and management changes mean the investor base is split between long-term conviction and short-term tactical plays.

Key Investor Types: The Institutional Dominance

The ownership structure of Pulmonx Corporation is overwhelmingly institutional, which is typical for a commercial-stage medical device company that requires deep sector expertise to evaluate. Honestly, this is not a stock driven by the individual retail investor.

Institutional investors and hedge funds own roughly 91.04% of the outstanding shares. This high concentration means the stock price is highly sensitive to the buying and selling decisions of a few large players. For context, Primecap Management Co. is one of the largest holders, and you also see major index-tracking funds like BlackRock, Inc. and Vanguard Group Inc. holding significant positions.

Here's the quick math on the ownership breakdown, based on the most recent filings:

• Institutional Investors & Hedge Funds: ~91.04%
• Insiders (Executives/Directors): ~8.06%
• Retail/Individual Investors: The remaining small float, less than 1%.

The insider ownership is relatively healthy, suggesting management's interests are reasonably aligned with shareholders, but the institutional turnover is what you need to watch. For a deeper dive into the company's fundamentals, you should check out Breaking Down Pulmonx Corporation (LUNG) Financial Health: Key Insights for Investors.

Investment Motivations: Growth, Margin, and M&A Speculation

The primary attraction for investors is the massive, underpenetrated market for severe emphysema treatment. Pulmonx Corporation estimates the total addressable market to be around $12 billion globally, and its Zephyr Valve is a standard-of-care treatment in over 25 countries.

The bulls focus on the company's strong gross margin and international momentum. In the third quarter of 2025, the company reported a robust gross margin of 75%, plus international revenue grew by a solid 15% year-over-year. That's a high-margin product with global traction.

But the real-world execution risk is what drives the bear case. The company's updated full-year 2025 revenue guidance is now in the range of $89 million to $90 million, which is a revision downward from earlier forecasts. The company is still operating at a loss, reporting a net loss of $14.0 million (or $0.34 per share) in Q3 2025, and operating expenses are expected to be high, between $125 million and $126 million for the full year 2025. This means investors are betting that the high gross margin will eventually translate to profitability as sales scale up.

A secondary motivation, particularly for hedge funds, is the possibility of a merger and acquisition (M&A) event. Some analysts openly suggest that the most logical endgame is for a larger medical device conglomerate to acquire Pulmonx Corporation to gain immediate access to the Zephyr Valve's technology and market, which could unlock significant value by cutting the high selling, general, and administrative (SG&A) costs.

Investment Strategies: Long-Term Growth vs. Event-Driven Trading

You see two distinct strategies at play here, reflecting the risk-reward profile of a high-growth, unprofitable med-tech stock.

Long-Term Growth and Index Investing:

This is the strategy of the large mutual fund complexes like Vanguard and BlackRock. They are buying Pulmonx Corporation not for a quick flip, but for its long-term potential in the healthcare sector, often through index funds that track the small-cap growth universe. They believe in the multi-year adoption curve of the Zephyr Valve and the eventual path to profitability.

Short-Term Trading and Speculative Value:

Hedge funds are much more tactical. They employ event-driven strategies, trading around earnings reports, FDA announcements, and management changes. You see this clearly in the recent 13F filings, where funds like Millennium Management LLC and Citadel Advisors LLC are either drastically increasing or decreasing their positions quarter-to-quarter. Also, with the stock trading near its 52-week low, some investors are treating it as a speculative value play, seeing the average analyst price target of $6.75 as a massive, asymmetric upside opportunity, despite the execution risks.

The recent management transition, including the reappointment of Glen French as CEO in late 2025, is a major catalyst that short-term traders are actively positioning around.

Institutional Ownership and Major Shareholders of Pulmonx Corporation (LUNG)

You need to understand who owns Pulmonx Corporation (LUNG) to truly grasp the stock's near-term volatility, and the answer is simple: institutional money controls the narrative. As of late 2025, institutional investors-the mutual funds, pension funds, and hedge funds-hold a commanding stake of approximately 91.04% of the company's stock.

This high concentration means that a few large players dictate stock price movement and have significant leverage over corporate strategy. When a handful of firms own that much of the float (the shares available for trading), their buying or selling isn't just noise; it's a seismic event for the stock price. The sheer weight of this ownership structure is why you see such sharp reactions to news, good or bad.

The Heavy Hitters: Top Institutional Investors in LUNG

The investor profile for Pulmonx Corporation is dominated by a mix of long-only growth managers and passive index funds, plus a healthy dose of active hedge funds. The largest shareholders, based on their September 30, 2025, 13F filings, are the firms you'd defintely expect to see in a growth-oriented medical technology company. These firms aren't just holding shares; they are the foundation of the stock's liquidity.

Here's the quick math on the top holders, showing their stake as of the end of the third quarter of 2025:

Notice the mix: Primecap Management Co/ca/ is the largest single holder, a classic growth investor, but Vanguard Group Inc. and BlackRock, Inc. are also in the top tier. Their presence is largely due to their index funds, which must hold the stock because it is part of an index like the Russell 2000. Their buying is mechanical, but their sheer size still matters.

Recent Shifts: Who's Selling and Why

The most telling story is in the recent ownership changes, especially during the third quarter of 2025. This period saw Pulmonx Corporation's stock price under pressure, and institutional money reacted decisively. We saw a clear pattern of large, established funds reducing their exposure, while some smaller, more aggressive hedge funds stepped in.

For example, Fmr Llc, a major institutional player, aggressively cut its stake by nearly 48.975% in Q3 2025, removing over 2 million shares. Deerfield Management Company, L.P. also removed a massive 1,575,901 shares, a 45.5% reduction. This is a strong signal of lost conviction from some of the most influential healthcare investors.

• Significant Selling: Fmr Llc reduced its stake by almost half, a huge vote of no confidence.
• Strategic Buying: Silvercrest Asset Management Group Llc boosted its position by 35.858%.
• Hedge Fund Activity: Citadel Advisors LLC, a major hedge fund, increased its position by a staggering 213.5% as of November 17, 2025, suggesting a short-term trading or deep-value play.

The selling pressure from the large, long-term holders like Primecap Management Co. (a 4.027% trim) and Fmr Llc is directly tied to the company's financial performance. Pulmonx Corporation updated its full-year 2025 revenue guidance to a range of only $89 million to $90 million, down from earlier expectations, with a net loss of $14.0 million in Q3 2025 alone. When the revenue growth story falters, these funds head for the exit.

The Institutional Impact on Strategy and Stock Price

The actions of these large investors have a direct, tangible effect on both the stock price and the company's boardroom. When a stock is trading near its 52-week low, as LUNG was in late 2025, the institutional owners start asking tough questions. The most concrete evidence of this pressure is the recent executive shake-up.

In October 2025, Pulmonx Corporation announced a major leadership transition, with CEO Steve Williamson resigning and Glen French being reappointed as CEO. This kind of swift management change is often a direct response to poor stock performance and a loss of confidence from major institutional shareholders. They essentially force a change in leadership to try and salvage their investment.

The institutional selling also amplifies the negative sentiment from Wall Street. Multiple analysts have recently cut their price targets, with some dropping to as low as $2.50 (Piper Sandler) and $3.00 (Wells Fargo). When the largest owners are selling into a market where analysts are downgrading, the stock price has no floor. This is a classic case of institutional investors voting with their feet, forcing the company to pivot its operational strategy to focus on profitability and growth acceleration. You can read more about the company's core business model and history here: Pulmonx Corporation (LUNG): History, Ownership, Mission, How It Works & Makes Money.

Key Investors and Their Impact on Pulmonx Corporation (LUNG)

You need to know who is driving the bus at Pulmonx Corporation (LUNG), and right now, the smart money is showing a mixed signal. While institutional ownership is high, the recent trend shows some major funds are trimming their positions, which puts pressure on the stock price and signals caution about near-term US market execution.

As of the third quarter of 2025, institutional investors collectively own a substantial portion of the company, approximately 46.32% of the stock, but it's the names and their recent actions that matter most. The top institutional holder is Primecap Management Co./ca/, a firm known for its long-term, patient growth strategy. They held a significant stake of over 5.16 million shares, valued around $13.38 million at the end of the second quarter of 2025. To be fair, even they trimmed their position slightly, selling 250,080 shares, a 4.6% reduction.

The presence of these large, well-known funds like Primecap, Vanguard Group Inc, and BlackRock, Inc. suggests a long-term belief in the core technology-the Zephyr Endobronchial Valve (EBV) therapy-as a standard of care for severe emphysema. You can read more about the company's foundation and product in Pulmonx Corporation (LUNG): History, Ownership, Mission, How It Works & Makes Money. These big holders are passive investors (Schedule 13G filers) for the most part, but their sheer size means any large move can influence the stock's direction.

Recent Moves: The Tug-of-War in Q2/Q3 2025

The recent trading activity shows a clear divergence among major funds, which is typical for a medical technology company facing slower-than-expected US adoption. We saw some significant selling, but also a massive vote of confidence from a few key players. This is where the rubber meets the road.

• FMR LLC: Reduced their stake by a hefty 21.4% in Q2 2025, removing over 1.15 million shares.
• Deerfield Management Company, L.P.: Made an even more dramatic cut, removing over 1.57 million shares, a 45.5% reduction in Q2 2025.
• MILLENNIUM MANAGEMENT LLC: Went the other way, adding a massive 958,048 shares, an increase of over 459.5% in Q2 2025.

This kind of large-scale selling from firms like Deerfield and FMR puts downward pressure on the stock, especially when the company is already dealing with a management transition and revised financial guidance. For the full year 2025, Pulmonx Corporation (LUNG) updated its total revenue guidance to a range of $89 million to $90 million, which reflects the slower US market growth. The company's cash and cash equivalents stood at $76.5 million as of September 30, 2025, which gives them a runway, but the execution risk is defintely elevated.

Insider Sentiment and Stock Influence

While institutional activity is mixed, the insider trading picture is overwhelmingly negative, which is a signal you cannot ignore. In the six months leading up to October 2025, insiders executed 27 sales compared to only 1 purchase. This includes sales by the former President and CEO, Steven S. Williamson, who sold 19,571 shares for an estimated $46,495, and the General Counsel, David Aaron Lehman, who sold 20,226 shares for an estimated $48,366.

Here's the quick math: when the people who know the company best are selling, it suggests they see less upside than the public market might imply, regardless of the strong Q3 2025 gross margin of 75%. This insider selling, coupled with the management change in October 2025, creates a headwind. The new CEO, Glen French, will need to quickly stabilize the U.S. market and show a clear path to achieving the full-year operating expense guidance of $125 million to $126 million to regain investor confidence. The stock price, which was trading near its 52-week low of $1.31 in November 2025, reflects this skepticism.

Market Impact and Investor Sentiment

You're looking at Pulmonx Corporation (LUNG) and trying to figure out if the big money is running for the exits or quietly accumulating shares. Honestly, the investor sentiment right now is a mixed bag, best described as cautious-to-neutral, with a clear 'Hold' consensus from most Wall Street analysts. Institutional ownership, however, remains remarkably high, which is a key signal.

As of late 2025, institutional investors-the mutual funds, pension funds, and hedge funds-own a significant portion of the company, with figures hovering around 91% to 93.49% of shares outstanding. That's a huge vote of confidence in the long-term viability of their core product, the Zephyr Valve, but it also means the stock price is highly sensitive to institutional trading. It's a crowded trade, so to speak.

The largest institutional holder is Primecap Management Co., which held 4,956,691 shares, representing 12.16% of the company, as of September 29, 2025. But here's the rub: Primecap Management Co. actually trimmed its stake by 4.0% in the most recent reporting period, selling off shares. This move, plus insider selling of about $655k over the last year, signals that some major players are taking profits or reducing risk at current levels. That's a red flag you can't ignore.

• Institutional ownership is high, but key holders are trimming.
• Insider selling suggests a lack of confidence from the top.
• The market is waiting for a clear path to profitability.

Recent Market Reactions to Ownership Shifts

The market's reaction to news has been volatile, which is typical for a medical technology company trading near its 52-week low of $1.31. The most telling recent move came in October 2025 when the company announced preliminary third-quarter 2025 revenue of $21.5 million and the return of former CEO Glen French. The stock surged 33.33% in after-hours trading on that news. That's a massive spike.

This big jump wasn't just about beating the Q3 revenue estimate; it was a strong reaction to a leadership change, suggesting investors were defintely unhappy with the previous management. The market is basically betting that the returning team can execute better on the commercialization of the Zephyr Valve. But, to be fair, the overall trend is still weak, as the stock is still down significantly from its 52-week high of $9.37.

On the flip side, when large institutional funds like Primecap Management Co. file to reduce their position, the market often sees a muted, but steady, downward pressure. It's not a single-day crash, but a slow bleed as other institutions follow suit or market makers adjust their expectations for future selling pressure.

Analyst Perspectives: The 'Hold' Consensus and Price Targets

The consensus rating from the ten brokerages covering Pulmonx Corporation (LUNG) is a firm 'Hold.' This isn't a 'Sell,' but it's not a ringing endorsement either. It means analysts see the company as fairly valued at its current price, with both significant risks and opportunities balancing out. The average 12-month price target is around $6.81, which implies a massive upside from the current trading price, but this average is skewed by a wide range of forecasts.

Here's the quick math on the analyst range:

What this estimate hides is the recent trend of target cuts. Several analysts have recently lowered their price targets-Wells Fargo cut to $3.00 (Equal Weight) and Piper Sandler to $2.50 (Neutral). This signals a weaker near-term outlook despite the Q3 revenue of $21.5 million beating estimates. The full-year 2025 revenue guidance was even lowered to a range of $89 million to $90 million, down from a prior forecast of $90 million to $92 million, which is a clear sign of management realism, but also a drag on growth expectations. If you want a deeper dive into the numbers behind this caution, check out Breaking Down Pulmonx Corporation (LUNG) Financial Health: Key Insights for Investors.

The impact of key investors is subtle: the presence of big names like BlackRock, Inc. and The Vanguard Group, Inc. (holding 6.56% and 5.50% respectively) provides a floor for the stock, as they are mostly passive index funds. But the active funds reducing their positions is what matters. The analyst community is essentially saying: great technology, good gross margin (Q3 2025 was 75%), but the path to controlling the $125 million to $126 million in full-year 2025 operating expenses and achieving profitability remains long and uncertain. My advice: track the next quarterly institutional filings closely.