Mark Massey's Top Holdings: Amazon, Transdigm Lead Portfolio as of Dec 31, 2025
Mark Massey's portfolio, valued at over $5.1 billion as of Dec 31, 2025, is dominated by Amazon and Transdigm, with significant allocations in Microsoft and other top holdings.
As of December 31, 2025, Mark Massey's portfolio at AltaRock Partners is valued at over $5.1 billion, showcasing a concentrated position in high-growth sectors. His top holdings reflect a strategic focus on technology and industrials, with Amazon.com Inc. (AMZN) leading the portfolio allocation at 33.1%, followed closely by Transdigm Group Inc. (TDG) at 25.28%. This investor profile, detailed on InsiderSet, provides insights into the holdings of top executives at prominent companies.
Amazon.com Inc. (AMZN), categorized under Consumer Cyclical, represents the largest position in Massey's portfolio. With a total stock value of approximately $1.69 billion, this stake accounts for nearly one-third of the total portfolio. The position saw a slight reduction in shares during the period, decreasing by 0.32% or 243,719 shares, though the stock value increased significantly due to market appreciation. Investors interested in analyzing Massey's stake in Amazon can explore further details on InsiderSet.
Transdigm Group Inc. (TDG) is the second-largest holding, comprising 25.28% of the portfolio with a total stock value of $1.29 billion. This stock, classified under the Industrials sector, experienced a minor reduction in shares (-0.72%) and a corresponding decrease in the position's value during the period. For more information on Transdigm's performance and its relevance to investors like Mark Massey, visit InsiderSet.
Microsoft Corporation (MSFT), a Technology stock, holds a significant allocation of 19.75% or approximately $1.01 billion in the portfolio. This position saw substantial changes during the period, with shares decreasing by 18.95% or 486,910 shares, indicating a significant reduction in the stake. Despite this reduction, the stock value remained substantial due to Microsoft's market performance. Learn more about Microsoft's stock and its appeal to investors like Mark Massey on InsiderSet.
The portfolio also includes several Financial Services holdings, including Moody's Corporation (MCO), Mastercard Inc. (MA), and Visa Inc. (V). Moody's, with an 8.16% allocation and a stock value of $416 million, experienced a notable reduction in shares (-14.15%) during the period. Mastercard and Visa, both at around 6% and 3.55% allocations respectively, also saw share reductions of 7.23% and 3.16%. Explore Mastercard's stock profile on InsiderSet and Visa's on InsiderSet.
Completing the top holdings is Alphabet Inc. (GOOGL), representing a smaller but still notable 1.04% allocation with a stock value of $53 million. This position saw a dramatic reduction in shares (-50.81%) during the period, significantly impacting the portfolio allocation. For insights into Alphabet's performance and its relevance to investors, check out InsiderSet.