Mark Massey's portfolio
Ultra-concentrated quality-value with very few positions and multi-year holding periods.
What changed in Q2 2026
Compared with the previous 13F. Values are as reported at quarter end. How to read a 13F.
New positions
None this quarter.
Added to
- MicrosoftMSFT$871M
- MastercardMA$393M
- Visa Inc. Class AV$287M
Trimmed
- Amazon.comAMZN$1.4B
- Transdigm GroupTDG$1.2B
- MoodysMCO$137M
- Alphabet Inc Class AGOOGL$15M
- Hilton WorldwideHLT$5M
Sold out
None this quarter.
Holdings
8 US-listed positions in the Q2 2026 13F, largest first.
| Stock | % of portfolio | Value | Shares | Last quarter |
|---|---|---|---|---|
| Amazon.comAMZN | 32.21% | $1.4B | 5,729,972 | Trimmed |
| Transdigm GroupTDG | 27.51% | $1.2B | 875,755 | Trimmed |
| MicrosoftMSFT | 20.54% | $871M | 2,334,482 | Added |
| MastercardMA | 9.26% | $393M | 764,507 | Added |
| Visa Inc. Class AV | 6.77% | $287M | 836,470 | Added |
| MoodysMCO | 3.23% | $137M | 302,624 | Trimmed |
| Alphabet Inc Class AGOOGL | 0.35% | $15M | 41,994 | Trimmed |
| Hilton WorldwideHLT | 0.12% | $5M | 15,202 | Trimmed |
By sector
Share of the reported value.
Reported value over time
Total 13F value at each quarter end.
Questions
What stocks does Mark Massey own?
In the Q2 2026 13F, AltaRock Partners LP reported 8 US stock positions worth $4.2B. The largest: Amazon.com (AMZN) 32.2%, Transdigm Group (TDG) 27.5%, Microsoft (MSFT) 20.5%, Mastercard (MA) 9.3%, Visa Inc. Class A (V) 6.8%.
What did Mark Massey buy last quarter?
In Q2 2026: added to Microsoft (MSFT); added to Mastercard (MA); added to Visa Inc. Class A (V).
When is Mark Massey's next 13F?
13F filings are due 45 days after each quarter ends. The Q3 2026 filing is due by November 14, 2026.
More investors
13F filings list US-listed long positions (and some options) held at quarter end. They leave out short positions, cash, bonds and non-US holdings, and arrive up to 45 days after the quarter ends, so the investor may have traded since. Information only, not investment advice.