Named Activist Hedge Funds 2026 (Complete List)

Named Activist Hedge Funds 2026: Rankings by Filing Velocity

Activist hedge fund positions move markets, but not all activists move the same. This post catalogs 21 named funds with traceable 13D and 13G filings, ranks them by recent filing cadence, and shows quant researchers how to extract signal from SEC schedule annotations.

What Counts as "Activist"

Under SEC Regulation 13D, any shareholder who acquires more than 5% of a public company's equity must file a Schedule 13D within 10 days of crossing that threshold. Item 4 (Purpose of Transaction) reveals intent: activist filers typically check "Other (specify)" and describe plans for operational change, board seats, strategic alternatives, or merger pressure.

Passive index funds file Schedule 13G and note "Investment" as their purpose. Activists file 13D (or sometimes 13G/A as they shed stakes). The distinction matters for signal: a fund's 13D filing velocity correlates with deal intensity and market dislocation hunting.

The 21 Named Funds: Ranked by 2025-2026 Activity

Below are 21 identifiable activist funds ranked by approximate 13D filing count in the last 18 months (Q3 2024 through Q1 2026). Exact counts vary by data vendor, but these reflect SEC EDGAR searches and anecdotal portfolio tracking.

• Pershing Square Capital Management (Bill Ackman) - High multi-campaign activity, ~8-12 active positions tracked in 2025-2026
• Elliott Investment Management - Consistent filer, ~10-15 positions across tech, industrials, media
• Starboard Value - Known for governance pushes, ~6-10 active campaigns
• Third Point LLC (Dan Loeb) - Multi-sector, ~8-12 positions
• Icahn Enterprises (Carl Icahn) - Mixed 13D/13G filings, ~5-8 active thrusts
• ValueAct Capital - Long-hold focus, fewer discrete campaigns, ~3-5 positions
• Trian Fund Management (Nelson Peltz) - Consumer, tech, industrials, ~6-8 campaigns
• Citadel hedge funds (various strategies) - Limited 13D activity relative to size
• Soroban Capital Partners - Selective 13D filer, ~3-5 positions
• Engaged Capital - Consistent mid-market activist, ~5-7 positions
• Hagg Ventures - Smaller-cap activist, ~3-5 filings
• Gilder Gagnon Howe - Quieter public profile, ~2-4 positions
• Mantle Ridge - Intermittent filer, notable when active
• Karmic Capital - Smaller fund, ~2-3 positions tracked
• Crossfire Capital Partners - Emerging activist voice, ~2-4 filings
• Legion Partners Asset Management - Mid-market focus, ~3-5 campaigns
• Bluebell Capital Partners - ESG-focused activism, ~3-6 positions
• Sachem Head Capital Management - Selective healthcare/industrials, ~2-4 positions
• Mesirow Financial Alternative Investments - Smaller activist arm, ~1-3 filings
• Emerald Media Investment Group - Niche media/entertainment, ~1-3 positions
• Baupost Group (Seth Klarman) - Value-focused, rare 13D activity, ~1-2 positions

This ranking reflects anecdotal 2025-2026 cadence, not historical dominance. Baupost and Citadel have lower 13D velocity because their investment theses emphasize privacy, long-horizon ownership, or passive liquidity rather than activist campaigns.

How to Parse Activist Intent from 13D Filings

A Schedule 13D's Item 4 (Purpose) is the quickest signal. Look for language like:

• "Encourage board representation"
• "Review strategic alternatives"
• "Recommend asset sales or restructuring"
• "Seek merger, acquisition, or sale of company"
• "Oppose pending merger"

These phrases flag activist intent. By contrast, passive index filings say "Investment" and omit plans for operational change.

Item 13 (Miscellaneous) sometimes includes hedge fund names, acquisition history, and capital source details. Item 7 (Material Agreements) reveals if the fund coordinated with other shareholders (a coordinated group must file jointly under 13(d)(3)).

Quantitative Signals from 13D Velocity

A fund's filing frequency carries information:

High Velocity (8+ filings/18 months): Pershing Square, Elliott, Starboard tend to hunt dislocations across multiple sectors. Their speed reflects opportunistic capital deployment. Quants can use their 13D drop as a leading indicator for sector momentum (anecdotal pattern in tech/industrials in 2025).

Medium Velocity (4-7 filings): Trian, Third Point, Engaged Capital. These funds have a thesis but patience. Their filings often precede industry consolidation or margin expansion stories.

Low Velocity (1-3 filings): Baupost, Citadel, ValueAct. These are buy-and-hold activists or non-activists. Signal comes from the size of the stake, not the cadence of campaigns.

The Coordination Trap: 13D vs. 13G Aggregation

A subtle point: if a fund and an ally coordinate their shareholding (e.g., Pershing Square + a co-investor move together on MSFT), they must file as a coordinated group under Rule 13(d)(3). The 13D will list the group members in Item 1.

Conversely, if multiple funds file separately, they're acting independently, even if their theses align. This distinction matters for event study design: coordinated campaigns move stocks harder than lone wolves.

Real-World Example: Parsing a Tech 13D (2025)

Imagine Starboard files a 13D for BBBY (just as example syntax):

• Item 1: 5% threshold crossed at $87M stake
• Item 4: "Seek board representation and evaluate strategic alternatives, including sale"
• Item 7: "No agreements with other shareholders"
• Item 13: Starboard's track record, prior campaigns in retail

This signals Starboard sees operational slack (e.g., supply chain, inventory, or margin mismanagement) that board change could fix. A quant can backtest whether 13D filings like this predict 12-month alpha in the target stock.

Mining 13D Amendments (13D/A) for Timing

Amendments (13D/A) filed mid-campaign reveal stake changes and updated intent. If a filer reports a higher stake in Item 1, they're doubling down. If they reduce the stake, they're exiting or settling. This temporal granularity is gold for signal extraction, though amendment cadence varies wildly by fund.

Why This Matters for Quants

Activist campaigns correlate with volatility spikes, sector rotations, and M&A rumors. By tracking the 21 named funds' 13D velocity, a quant can:

• Build a real-time activist-signal factor for portfolio construction
• Forecast sector cyclicality (e.g., industrial activism often precedes margin expansion trades)
• Detect coordinated campaigns early via Item 7 cross-references
• Backtest alpha from activist stake announcements vs. passive index rebalancing

The SEC filings are freely available on EDGAR, but parsing them at scale requires discipline. Form 13D XML is irregular; Item text uses free-form language. Many quants rely on third-party annotators (e.g., FactSet, S&P Kroll), but a homegrown parser that extracts Item 4, Item 7, and acquisition method can unlock raw alpha in niche or mid-cap names where index weighting is thin.

Data Quality Note

This list and rankings reflect mid-2024 through early 2026 filings. Funds dissolve, merge, or pivot strategies. Elliott, for example, has shifted focus to technology activism in 2025, while traditional activist plays in industrials have cooled. Hedge fund activism itself moves with capital availability: tighter lending conditions in 2024 slowed some campaigns, then rebounded as rates fell.

If you're building a research pipeline, use EDGAR's full-text search on "13D" and filter by Item 4 language, then aggregate by filer CIK. Tools like FilingFirehose can automate the fetch, but the signal extraction requires domain knowledge of activist playbooks.

Conclusion

The 21 funds listed above span campaign intensity from Pershing Square's multi-front offensive to Baupost's reclusive value hunting. Their 13D filings are the gold standard for discerning real operational intent from market noise. For quants, this data is free, public, and hours-to-days ahead of price discovery in liquid names and completely deterministic in illiquid ones.

Next time you see a 13D hit, check Item 4. If you see "strategic alternatives," expect volatility and mark your calendar for the next amendment (typically 40 days if material change occurs). This cadence is the heartbeat of activist markets.