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AltaRock Partners LP
Mark T. Massey · Hedge Fund · Value
AltaRock Partners LP is a highly concentrated investment management firm based in West Palm Beach, Florida. Founded in 2002 by Mark T. Massey, who previously worked at Seth Klarman's Baupost Group, the firm restructured as a limited partnership in 2023. AltaRock is distinguished by its focused portfolio, typically consisting of fewer than ten high-quality companies characterized by sustainable competitive advantages and wide economic moats. Managing approximately $5.4 billion in assets, the firm provides investment advisory services primarily to institutional investors and high-net-worth individuals through privately offered pooled vehicles. The institution's approach centers on long-term capital growth and rigorous fundamental analysis.
Simulated Performance
| Metric | Value |
|---|---|
| Total return | +2.5% |
| YTD return | +0.5% |
| Sharpe ratio | -0.23 |
| Win rate | 44% |
| AUM | $4.7B |
| Inception | Oct 1, 2025 |
| Updated | Sep 11, 2026 |
Institution Status
| Field | Value |
|---|---|
| AUM | $4.7B |
| Turnover | Low (<15%) |
| Avg holding | 18 Months |
| Inception | Oct 1, 2025 |
| Website | http://www.altarockpartners.com/ |
Current Holdings
Updated on Sep 11, 2026.
| Ticker | Name | Portfolio % | Return |
|---|---|---|---|
| AMZN | Amazon.com Inc | 32.3% | +13.8% |
| MSFT | Microsoft Corporation | 25.5% | -3.6% |
| TDG | Transdigm Group Incorporated | 22.0% | -12.1% |
| MA | Mastercard Inc | 9.7% | -1.1% |
| V | Visa Inc. Class A | 6.8% | +3.1% |
| MCO | Moodys Corporation | 3.3% | -0.1% |
| GOOGL | Alphabet Inc Class A | 0.3% | +36.2% |
| HLT | Hilton Worldwide Holdings Inc | 0.1% | +17.8% |
Recent activity
| Date | Action | Ticker | Weight |
|---|---|---|---|
| Aug 31, 2026 | BUY | TDG | 23.2% → 22.0% |
| Aug 31, 2026 | SELL | MCO | 8.1% → 3.3% |
| Aug 31, 2026 | BUY | GOOGL | 0.3% → 0.3% |
| Aug 31, 2026 | BUY | V | 3.5% → 6.8% |
| Aug 31, 2026 | BUY | MA | 5.5% → 9.7% |
Investment Style Analysis
AltaRock Partners LP is widely recognized for employing a Value strategy. As of Sep 11, 2026, the firm oversees approximately $4.7B in assets under management (AUM). The portfolio demonstrates a clear preference for the Internet Retail and Software - Infrastructure sectors, reflecting a high-conviction approach to capital allocation.
Recent Market Moves
During the latest rebalancing period ending Aug 31, AltaRock Partners LP made a significant move by increasing exposure to TDG. This adjustment aligns with the fund's dynamic approach to risk management and capital deployment in current market conditions.
Investment Philosophy
AltaRock Partners follows a long-term, value-oriented investment philosophy inspired by the principles of Warren Buffett and Charlie Munger. The firm focuses on acquiring equity stakes in a select group of undervalued businesses that possess durable competitive advantages and strong economic moats. Their strategy is characterized by extreme portfolio concentration and a 'buy-and-hold' mentality, treating investments as ownership in a diverse conglomerate of businesses rather than mere stock trades. The research process emphasizes qualitative analysis of business models, historical cash flows, and management alignment, specifically targeting companies with high profitability and consistent share buyback programs.
Disclaimer
The content provided on this page, including the simulated portfolio performance, holdings analysis, and AI-generated insights, is for informational and educational purposes only. It does not constitute financial advice, investment recommendations, or an offer to buy or sell any securities. All data is derived from historical SEC 13F filings and other public disclosures, which have a reporting lag. The "Simulated Performance" is a hypothetical reconstruction based on past disclosures and does not represent the actual returns of the institution. Past performance is not indicative of future results. Tritonix.ai is not affiliated with AltaRock Partners LP.
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Frequently asked questions
How is the simulated portfolio for AltaRock Partners LP constructed?
This simulation is powered by Tritonix AI using official SEC filings. We focus on the "Best Ideas" by filtering for only the Top 20 largest holdings and rebalancing them to 100%. The simulation tracks performance starting from Oct 1, 2025. Our AI monitors for updates every Monday to capture major shifts. This concentrated approach highlights the manager's true stock-picking skill and mirrors their actual investment returns.
What is AltaRock Partners LP's largest holding?
As of the latest filing, AltaRock Partners LP's top position is Amazon.com Inc (AMZN), representing 32.3% of the portfolio. This reflects a high-conviction bet by the institution.
What is AltaRock Partners LP's historical performance and risk profile?
Our simulation indicates a total return of +2.5% with a win rate of 44%. Notably, the portfolio maintains a Sharpe Ratio of -0.23, suggesting an standard level of risk-adjusted returns compared to the broader market.
What sectors does AltaRock Partners LP primarily invest in?
AltaRock Partners LP has a strong preference for the Internet Retail sector, which makes up 32.3% of their disclosed assets. The portfolio also has exposure to Software - Infrastructure, indicating a specific thematic focus.
Is AltaRock Partners LP's portfolio concentrated or diversified?
AltaRock Partners LP runs a highly concentrated portfolio with 8 disclosed positions. The top 3 holdings alone account for 79.8% of the total portfolio weight, suggesting a strategy that favors deep research into a few key names.
How has AltaRock Partners LP performed in 2026?
Our AI-simulated model portfolio for AltaRock Partners LP tracks a Year-to-Date (YTD) return of +0.5%. This metric helps investors gauge the institution's effectiveness in the current market environment.
Does Mark T. Massey manage AltaRock Partners LP directly?
Yes, Mark T. Massey serves as the key portfolio manager for AltaRock Partners LP, overseeing the investment strategy and final capital allocation decisions.