
AltaRock Partners
Mark Massey runs AltaRock Partners, a value-investing firm he founded in 2002. Before that he worked at Seth Klarman's Baupost Group, the Boston firm known for its careful, margin-of-safety approach to undervalued securities. Massey holds an MBA from Harvard Business School, as does Scott Bradford, who joined AltaRock as an early analyst, became a managing member, and left in 2017; Bradford earlier worked at Fiduciary Management Associates. AltaRock's strategy is deliberately small and intensely concentrated. The firm typically holds only about ten companies at a time, and Massey treats them as permanent ownership stakes rather than trades to be flipped. He looks for businesses with wide, durable competitive moats, strong profitability, reliable free cash flow, and attractive prices, spread across diverse regions. His method is almost entirely qualitative — he largely skips screens and instead studies business models, management, and how long a company's advantage can survive. He reads stock buybacks as a telling signal, since management that repurchases its own shares is betting on its own competitive durability. The approach is openly inspired by Warren Buffett and Charlie Munger's Berkshire Hathaway. The story behind the firm is its lineage. Massey trained under Klarman, then built a shop that deliberately does the opposite of most hedge funds — own a handful of companies, hold them for years, and leave them alone.
Avg. holding
7.7 qtrs
Longest current
≥47 qtrs
Mastercard Inc · MA
Win rate est.
71%
based on 7 of 11 closed positions
Turnover rhythm
0.7 / qtr
100% coverage · 34 entries + exits over 47 filed qtrs
One year after exit est.
est. +2.1%
based on 7 of 13 closed positions
| Security | Period | Return est. |
|---|---|---|
| Charter Communications, Inc. | Q2 2016–Q1 2025 | est. +60.0% |
| O Reilly Automotive Inc | Q2 2018–Q1 2020 | est. +42.4% |
| Fair Isaac Corp | Q2 2024–Q4 2025 | est. +33.0% |
| Westinghouse Air Brake Technologies Corporation | Q3 2016–Q2 2018 | est. +27.5% |
| Berkshire Hathaway Inc | Q2 2016–Q3 2016 | est. +2.5% |
based on 7 of 11 closed positions
| Security | Period | Return est. |
|---|---|---|
| Meta Platforms, Inc. | Q4 2020–Q2 2022 | est. -30.3% |
| Booking Holdings Inc. | Q1 2018–Q4 2018 | est. -6.7% |
| Berkshire Hathaway Inc | Q2 2016–Q3 2016 | est. +2.5% |
| Westinghouse Air Brake Technologies Corporation | Q3 2016–Q2 2018 | est. +27.5% |
| Fair Isaac Corp | Q2 2024–Q4 2025 | est. +33.0% |
based on 7 of 11 closed positions
0 of 8 positions are held by no other tracked investor
Every current position is also held by another tracked investor.