This article summarizes the most significant insider trading activities disclosed on Tuesday, December 9, 2025, highlighting key executives selling substantial positions in their companies.
Top Insider Sells
• TransDigm Group INC (NYSE:TDG) saw Director Robert J. Small sell a total of 90,953 shares of common stock at a price of $1,335.72, according to a Form 4 filing with the Securities and Exchange Commission. The total value of the sale reached $121,487,741. The transactions involved selling 75,673 shares held by Stockbridge Fund, L.P., and 15,280 shares held by Stockbridge Partners LLC. Following these transactions, Stockbridge Fund, L.P. still holds 366,141 shares, while Stockbridge Partners LLC maintains 68,139 shares.
• UL Solutions Inc. (NYSE:ULS) had ten percent owner ULSE Inc. sell 12,500,000 shares of Class A Common Stock on December 5, 2025. The shares were sold at $78.00 per share, totaling $975,000,000. This transaction price sits slightly above ULS’s current trading price of $77.52, with the company carrying a market capitalization of $15.39 billion. On the same day, ULSE Inc. also converted 12,500,000 shares of Class B Common Stock into Class A Common Stock at no cost. Following these transactions, ULSE Inc. no longer owns any Class A Common Stock but directly holds 125,630,000 shares of Class B Common Stock.
• Axon Enterprise (NASDAQ:AXON) President Joshua Isner sold 19,600 shares of common stock on December 8, 2025, generating $11,052,006. The sales were executed across multiple transactions with prices ranging from $550.49 to $555.14. These transactions occurred while Axon’s stock trades near $546.66, having declined approximately 29% over the past six months.
• Datadog, Inc. (NASDAQ:DDOG) Chief Technology Officer Le-Quoc Alexis disposed of 53,912 shares of Class A Common Stock on December 8, 2025, for approximately $8.3 million. The sales occurred at weighted average prices ranging from $153.24 to $155.01 per share. On December 5, Le-Quoc also converted 123,000 shares of Class B Common Stock into Class A Common Stock.
• MongoDB, Inc. (NASDAQ:MDB) Director Botha Roelof executed multiple sales of common stock on December 5, 2025. The transactions involved 24,410 shares sold at prices ranging from $400.87 to $410.83 per share, totaling $10,085,418. Following these transactions, Botha Roelof indirectly holds 194,600 shares through estate planning vehicles and directly holds 1,130 shares.
Why Monitor Insider Trading?
Tracking insider transactions provides valuable insights into how a company’s executives and board members view their own stock’s prospects. When insiders buy shares, it often signals confidence in the company’s future performance. Conversely, insider selling may occur for various reasons including diversification, tax planning, or personal financial needs, but substantial selling by multiple insiders might warrant closer attention. While no single transaction should dictate investment decisions, insider activity patterns can serve as one important factor in a comprehensive investment analysis strategy.
This article was generated with the support of AI and reviewed by an editor. For more information see our T&C.








