Mark Massey of AltaRock Partners: Portfolio Shifts in Q4 2025
Mark Massey's portfolio at AltaRock Partners saw significant reductions in major holdings like Microsoft and Amazon, while maintaining strong positions in sectors like Industrials and Technology.
As of December 31, 2025, Mark Massey's portfolio at AltaRock Partners was valued at approximately $5.1 billion. The portfolio is heavily concentrated in large-cap technology and industrials stocks, with Amazon.com Inc (AMZN) and Transdigm Group Inc (TDG) leading the holdings by allocation percentage.
The most significant change during this quarter was the reduction in Microsoft Corp (MSFT) shares, which decreased by 18.95%. This substantial decrease in shares, representing a notable reduction in exposure to the Technology sector, was the largest percentage change among the top holdings.
Amazon.com Inc (AMZN) also saw a significant reduction, with a 3.22% decrease in shares, impacting the Consumer Cyclical sector allocation.
Transdigm Group Inc (TDG) experienced a smaller but still noteworthy reduction of 0.72% in its holdings, affecting the Industrials sector allocation.
Other holdings like Moody's Corp (MCO), Mastercard Inc (MA), Visa Inc (V), and Alphabet Inc (GOOGL) also saw decreases, ranging from 14.15% to 50.81% in shares, impacting the Financial Services and Communication Services sectors respectively.
No new positions were disclosed in this filing. Investors can explore Mark Massey's complete investment history and the companies he invests in by visiting his profile on Insiderset: Mark Massey at Insiderset.
For detailed information on each stock held, including company profiles, visit the respective pages on Insiderset: AMZN, TDG, MSFT, MCO, MA, V, GOOGL.