Mark Massey - AltaRock Partners Investment Strategy & Portfolio Analysis
How AltaRock Partners allocates capital, manages risk, and constructs its portfolio — based on SEC 13F filings.
As of Mar 31, 2026, Mark Massey's AltaRock Partners portfolio reflects a highly concentrated, high-conviction approach across 8 reported 13F positions. Portfolio returns are primarily driven by a small set of mega-cap compounders, with the top five holdings accounting for approximately 96% of total exposure and Amazon.com, alone contributing ~38%. Economic outcomes are highly concentrated in a narrow set of growth-oriented large-cap names. Exposure to high-growth and technology-oriented segments is elevated relative to peers, with performance anchored in growth-oriented names across consumer discretionary, industrials, and financials. The portfolio exhibits extremely low turnover, reinforcing a patient, conviction-led investment approach. Distinctive traits include Long-Term Holder, Highly Concentrated, Economically Concentrated.
Investment Style
Value, growth, quality, and behavioral classification from latest 13F holdings.
Primary type: Growth-Oriented Investor
Traits: Long-Term Holder, Highly Concentrated, Economically Concentrated
Turnover profile
Buy & Hold
Holding horizon
Long-Term
Portfolio Construction
Concentration and position sizing in the latest filing.
Portfolio construction is highly concentrated: top three names represent 80.5% of assets, top five 95.9%, and the largest single position is 38.2%.
Top 3 weight
80.5%
Top 5 weight
95.9%
Top 10 weight
100.0%
Largest position
38.2%
Top holdings: Amazon.com, Inc., Transdigm Group Incorporated, Microsoft Corporation, Moody's Corporation, Mastercard Incorporated — view full holdings
Sector Preferences
Where capital is allocated by sector.
Capital is tilted toward Consumer Cyclical and Industrials, with 5 sectors represented in the latest filing.
Leading sectors: Consumer Cyclical, Industrials, Financial Services
Risk Framework
Concentration, diversification, and turnover tolerance.
This investor accepts high single-name risk (largest position 38.2%, top ten 100.0%) and low economic diversification (HHI 0.15). Turnover tolerance maps to a buy & hold profile.
Largest position
38.2%
Top 10 weight
100.0%
Max sector
38.3%
Diversification
Low
Strategy Evolution
How the strategy changed between the two most recent filing periods.
Dec 31, 2025 → Mar 31, 2026
- Top-five concentration rose from 92.4% to 95.9%.
- Quarter-over-quarter portfolio weight turnover: 6.7%.
For trade-level changes, see the Activity page. View activity.
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