Lone Pine’s Non-AI Strategy Falters: 10 Non-AI Stocks Weighing Down Stephen Mandel’s 2026 Returns

7. TransDigm Group Incorporated (NYSE:TDG)

Lone Pine Capital’s Stake: $26 Million

YTD Decline in Share Price: 13%

TransDigm Group Incorporated (NYSE:TDG) is a long-term holding in the 13F portfolio of Lone Pine Capital. The fund first disclosed a stake in the company back in the fourth quarter of 2010. This holding comprised just under 3 million shares. By early 2012, Lone Pine had grown this stake to more than 3.3 million shares. Since then, the stock has featured consistently in the 13F portfolio of the fund, with minor exceptions. The latest position was opened in the fourth quarter of 2025 and comprises over 19,000 shares. The company designs, produces, and supplies aircraft components in the United States and internationally.

Elite investors are piling into TransDigm Group Incorporated (NYSE:TDG) stock because roughly 90% of the net sales of the firm come from proprietary products, most of which are sole-source. This gives the company unmatched pricing power in the aftermarket. As global air traffic grew by 4% year-over-year in early 2026, TDG saw high-margin commercial aftermarket sales jump, contributing to a massive 52.4% EBITDA margin. It collects high-margin revenue that is largely immune to the production delays hitting OEMs like Boeing. The firm has been on an aggressive acquisition streak as well. Earlier this month, TDG completed the $2.2 billion acquisition of Jet Parts Engineering and Victor Sierra Aviation. This follows the late 2025 integration of Simmonds Precision Products from RTX.