# AltaRock Partners portfolio: Q2 2026 13F holdings

Mark Massey’s AltaRock Partners: $4.2bn in 8 US holdings at Q2 2026, with buys and sells. Top: Amazon.com, Transdigm Group, Microsoft, Mastercard, Visa.

In Q2 2026, AltaRock Partners held 8 US-listed stocks worth $4.2bn. Its biggest move was cutting Amazon.com (24% fewer shares, now 32%), followed by cutting Moody's (65% fewer shares, now 3.2%). Its largest holding is Amazon.com at 32%.

13F for the quarter ending 2026-06-30, filed 2026-08-17 ([filing](https://www.sec.gov/Archives/edgar/data/1631014/000110465926097527/0001104659-26-097527-index.htm)). $4.2bn in US-listed holdings.

## 13F holdings

| Company | Value | Portfolio | Change | Q1 2026 |
| --- | --- | --- | --- | --- |
| Amazon.com (AMZN) | $1.4bn | 32.2% | Trimmed -24% | 38.2% |
| Transdigm Group (TDG) | $1.2bn | 27.5% | Trimmed -3.7% | 25.5% |
| Microsoft (MSFT) | $871m | 20.5% | Added +25% | 16.8% |
| Mastercard (MA) | $393m | 9.3% | Added +46% | 6.3% |
| Visa (V) | $287m | 6.8% | Added +68% | 3.6% |
| Moody's (MCO) | $137m | 3.2% | Trimmed -65% | 9.1% |
| Alphabet (GOOG) | $15.0m | 0.3% | Trimmed -3.2% | 0.3% |
| Hilton Worldwide (HLT) | $5.0m | 0.1% | Trimmed -0.9% | 0.1% |

Source: SEC filings, via moatshark (https://www.moatshark.com/m/altarock-partners). Values traded and returns are estimates. Not investment advice. Built 2026-10-21.