AltaRock Partners
AltaRock Partners
AltaRock Partners (AltaRock Partners) discloses a $4.24B portfolio across 8 US-listed positions in the latest 13F filing (2026Q2, filed Aug 17, 2026). The largest holding is AMZN at 32.2% of the book. The biggest move of the quarter: trimmed the AMZN share count by 24% (position now $1.37B). Mechanically cloning this 13F returned 16.5%/yr over the past 11.4 years, versus 13.5%/yr for the S&P 500 across that identical 11.4-year window.
Holdings (8) · click any column to sort
| #↑ | Ticker | Issuer | % Port. | This Q | History | Value |
|---|---|---|---|---|---|---|
| 1 | AMZN | 32.2% | $1.37B | |||
| 2 | TDG | 27.5% | $1.17B | |||
| 3 | MSFT | 20.5% | $871M | |||
| 4 | MA | 9.3% | $393M | |||
| 5 | V | 6.8% | $287M | |||
| 6 | MCO | 3.2% | $137M | |||
| 7 | GOOGL | 0.4% | $15M | |||
| 8 | HLT | 0.1% | $5M |
- 1AMZNport32.2%val$1.37BAmazon.com Incthis Q -24%·18q
- 2TDGport27.5%val$1.17BTransdigm Group Incthis Q hold·40q
- 3MSFTport20.5%val$871MMicrosoft Corpthis Q +25%·21q
- 4MAport9.3%val$393MMastercard Inc - Athis Q +46%·40q
- 5Vport6.8%val$287MVisa Inc-class A Sharesthis Q +68%·40q
- 6MCOport3.2%val$137MMoody's Corpthis Q -65%·40q
- port0.4%val$15MAlphabet Inc-cl Athis Q hold·27q
- 8HLTport0.1%val$5MHilton Worldwide Holdings INthis Q hold·7q
2026Q2 moves, by size (5)(expand ↓)
| Ticker | Issuer | Move | % Port. | Δ Shares | Value |
|---|---|---|---|---|---|
| AMZN | Amazon.com Inc | TRIM | 32.2% | -24% | $1.37B |
| MSFT | Microsoft Corp | ADD | 20.5% | +25% | $871M |
| MA | Mastercard Inc - A | ADD | 9.3% | +46% | $393M |
| MCO | Moody's Corp | TRIM | 3.2% | -65% | $137M |
| V | Visa Inc-class A Shares | ADD | 6.8% | +68% | $287M |
- TRIMAMZN32.2%Amazon.com IncΔ -24%·$1.37B
- ADDMSFT20.5%Microsoft CorpΔ +25%·$871M
- ADDMA9.3%Mastercard Inc - AΔ +46%·$393M
- TRIMMCO3.2%Moody's CorpΔ -65%·$137M
- ADDV6.8%Visa Inc-class A SharesΔ +68%·$287M
About AltaRock Partners
AltaRock Partners is a Boston-based concentrated long-only equity manager founded by Jim Goetz and John Melas-Kyriazi, running what amounts to a high-conviction compounding portfolio: eight disclosed positions at last count, with the top five accounting for roughly 96% of a $4.1B book. The style sits in the Munger-influenced "wonderful businesses at fair prices" tradition — Amazon, TransDigm, Microsoft, Moody's, and Mastercard have been persistent core holdings, each chosen for durable pricing power and reinvestment runway. There are no known short positions, options overlays, or derivatives strategies that would create material divergence between the 13F and the actual portfolio; what you see is largely what they own. The 45-day disclosure lag is the primary friction for anyone attempting to clone the book — position-level changes can be meaningful given how few names are held, so a quarterly filing may already reflect a full turn in one of the top weights.
2026Q2 brief
2026Q2 activity: 3 conviction adds (top: MSFT, MA, V). Top 5 holdings: AMZN, TDG, MSFT, MA, V (96% of portfolio).
AI-generated. Not investment advice.
Filing history
AltaRock Partners's disclosed 13F portfolio value and position count by quarter — the trajectory across every SEC filing.
| Quarter | Positions | Portfolio value |
|---|---|---|
| Q2 2026 — what changed → | 8 | $4.24B |
| Q1 2026 — what changed → | 8 | $4.13B |
| Q4 2025 — what changed → | 8 | $5.10B |
| Q3 2025 — what changed → | 9 | $5.47B |
| Q2 2025 — what changed → | 9 | $5.48B |
| Q1 2025 — what changed → | 9 | $4.97B |
| Q4 2024 holdings | 10 | $4.94B |
| Q3 2024 holdings | 9 | $5.08B |
| Q2 2024 holdings | 9 | $4.86B |
| Q1 2024 holdings | 8 | $4.65B |
| Q4 2023 holdings | 8 | $4.48B |
| Q3 2023 holdings | 8 | $3.99B |
Values as disclosed at each quarter end. Older filings on EDGAR.
Multibaggers AltaRock Partners held
Stocks up 5x or more since AltaRock Partners first held them at conviction size — the holding record behind the returns. Longest unbroken run and largest book weight are shown for each.
- FICO22.4xFAIR ISAAC CORP6q straight · peak 1.33%
- AMZN13.8xAMAZON.COM INC17q straight · peak 38.2% · still holds
- TDG12.3xTRANSDIGM GROUP INC46q straight · peak 32.29% · still holds
- MSFT11.2xMICROSOFT CORP20q straight · peak 24.33% · still holds
- GOOGL10.1xALPHABET INC-CL A26q straight · peak 26.19% · still holds
- META10.0xMETA PLATFORMS INC-CLASS A6q straight · peak 24.38%
Six biggest of 11. Price multiple since the first quarter we observed a conviction holding (2014Q1 at the earliest), not AltaRock Partners's realized return — entry price and trades between filings aren't disclosed. Peak weight is share of disclosed US 13F book. All 129 multibaggers the cohort held →
Frequently asked questions
- What stocks does AltaRock Partners own?
- As of 2026Q2, AltaRock Partners's 13F discloses 8 positions worth $4.24B. The top five holdings: AMZN (32.2%), TDG (27.5%), MSFT (20.5%), MA (9.3%), V (6.8%). 13F filings cover long US-listed equities only — cash, bonds, shorts, and non-US positions are not disclosed.
- What did AltaRock Partners buy this quarter?
- In 2026Q2, the filing shows 0 new positions and 3 additions to existing holdings. The largest positions touched by buying: MSFT, MA, V.
- How big is AltaRock Partners's portfolio?
- $4.24B across 8 positions per the latest 13F (filed Aug 17, 2026). The top five holdings account for 96% of the disclosed book.
Similar portfolios
Explore more
Long US equity 13F-HR filings only — no shorts, no derivatives. SEC filings at EDGAR (CIK 0001631014). Not investment advice.