Insiders Put $12 Billion of Their Own Money In During Q4 2025: The 10 Companies Executives Bought Most Aggressively

TL;DR

• 1,733 corporate insiders made 4,839 open-market purchases across 1,020 companies in Q4 2025, totaling $12 billion.
• December dominated: $10 billion of the $12 billion total came in the final month of the quarter, a 10x spike from October.
• Healthcare led sectors: $786 million in insider buying across 51 healthcare companies, followed by Financial Services at $421 million.
• Biggest single buyer: GENMAB A/S poured $7.6 billion into partner Merus N.V. — the largest insider purchase of the quarter by a factor of 15x.
• Notable conviction bets: DoorDash insider Alfred Lin bought $100 million, the Mills family put $150 million into Medline, and BGC Group insiders collectively spent $248 million.

Why Insider Buying Matters

When a corporate executive writes a personal check to buy shares of their own company on the open market, it's one of the strongest signals in public markets. Unlike options exercises or automatic trading plans, open-market purchases represent a voluntary decision to put personal capital at risk — in a company the buyer knows better than almost anyone else.

Q4 2025 delivered one of the most active insider buying quarters in recent memory. Let's break down where executives and major stakeholders were deploying capital.

The $7.6 Billion Elephant: GENMAB's Strategic Bet on Merus

The single largest insider buying story of Q4 2025 was GENMAB A/S, the Danish biotech giant, accumulating $7.6 billion worth of Merus N.V. (MRUS) shares across 11 separate transactions at an average price of $97 per share. As a 10%+ owner, GENMAB's purchases signal deep conviction in Merus's bispecific antibody pipeline.

This single position accounts for 63% of all insider buying in the quarter. Strip it out, and the remaining 1,732 insiders still spent $4.4 billion — a healthy number that reflects broad-based confidence across sectors.

Beyond the Mega-Deal: Who Else Was Buying?

Excluding GENMAB, the most notable insider purchases reveal a mix of founder conviction, board-level confidence, and strategic positioning:

• Medline Inc. (MDLN) — $515 million: Directors Andrew J. Mills ($75M) and Charles N. Mills ($74.8M) led the charge, along with a third buyer. The Mills family has deep roots in Medline, and their collective $150M personal investment came shortly after the company's IPO.
• Immunovant (IMVT) — $350 million: Roivant Sciences, a director and 10%+ owner, made a single $350 million purchase at $21/share — a massive one-shot bet on the autoimmune therapy company.
• BGC Group (BGC) — $248 million: Three connected entities — Cantor Fitzgerald L.P., CF Group Management, and Brandon Lutnick — each put in $82.6 million. This coordinated insider accumulation signals the Cantor Fitzgerald ecosystem doubling down on its brokerage arm.
• Eastman Kodak (KODK) — $203 million: Two insiders made 9 purchases at an average price of $91/share. The legacy brand's pivot toward specialty chemicals and film continues to attract insider capital.
• Kymera Therapeutics (KYMR) — $173 million: A single buyer accumulated $173M at $86/share average — aggressive conviction in the protein degradation biotech.

Which executives made the biggest personal purchases in Q4 2025?

Beyond the institutional and 10%+ owner transactions, several individuals stood out for the sheer size of their personal bets:

• Daniel Reis-Faria, CEO of Flora Growth Corp. (FLGC), bought $150 million in a single transaction — a CEO betting the house on his own company.
• Jeffrey C. Smith purchased $111 million of Kenvue (KVUE), the Johnson & Johnson consumer health spinoff, in two transactions at $17.40/share.
• Alfred Lin, a DoorDash (DASH) insider, made 11 separate purchases totaling $100.3 million at an average of $194.51/share throughout Q4 — a pattern of steady accumulation rather than a single splash.
• Charles A. Davis bought $97 million of BETA Technologies (BETA) as a director in a single transaction — a massive vote of confidence in the electric aviation startup.
• Mario J. Gabelli, the legendary value investor, put $58.2 million into Gabelli Dividend & Income Trust across 4 transactions.
• Kelcy L. Warren, director of Energy Transfer LP (ET), bought $33.8 million in two transactions, while Richard D. Kinder, Executive Chairman of Kinder Morgan (KMI), spent $26 million in a single purchase. Two pipeline titans putting personal money into their own energy infrastructure plays.

The December Spike: What Triggered $10 Billion in a Single Month?

The monthly breakdown tells a dramatic story. October saw $951 million in insider buying from 400 unique buyers. November was similar at $1.06 billion from 956 buyers. Then December exploded to $10 billion from 612 buyers.

The GENMAB/MRUS mega-deal accounts for most of December's spike, but even excluding it, December buying was elevated. Year-end dynamics — including tax-loss harvesting creating buying opportunities, annual bonus deployments, and pre-earnings positioning — likely contributed to the surge.

Which sectors attracted the most insider buying in Q4 2025?

Where sector data is available, the breakdown reveals clear preferences:

• Healthcare: $786 million across 51 companies with 79 unique buyers — by far the most popular sector for insider purchases, reflecting biotech pipeline confidence and post-approval accumulation.
• Financial Services: $421 million across 93 companies — the broadest sector participation by company count, with insiders at banks, brokerages, and fintech firms buying their own stock.
• Technology: $248 million across 69 companies — notable for the variety of bets, from electric aviation to enterprise software.
• Consumer Cyclical: $149 million — including DoorDash and Under Armour, where Under Armour (UA) saw one insider buy $71 million across 10 transactions.
• Utilities: $110 million — steady infrastructure bets from energy pipeline insiders.

What does heavy insider buying mean for investors?

Academic research consistently shows that insider purchases outperform the market over 6-12 month horizons. A 2023 study in the Journal of Financial Economics found that stocks with cluster buying — multiple insiders purchasing within a short window — outperformed by an average of 7.2% annually.

The Q4 2025 data shows several cluster-buy signals: Medline (3 buyers), BGC Group (3 connected buyers), BETA Technologies (7 buyers), Navan (3 buyers including Horowitz), and Evommune (4 buyers). These are worth watching in the coming quarters.

Analyst's Take

The Q4 2025 insider buying data sends two clear signals. First, healthcare is where insiders have the most conviction — the sector attracted the highest dollar volume and features several large single-buyer positions. Second, the cluster buys in BGC, BETA Technologies, and Navan suggest coordinated confidence that's historically been more predictive than isolated purchases.

The December spike, once you strip out the GENMAB mega-deal, still shows elevated buying — suggesting insiders were taking advantage of year-end volatility to add to positions at prices they considered attractive.

Track insider activity for any stock on 13F Insight and set up alerts to catch the next wave of executive conviction buying.