Altarock
Manager: Mark Massey
ALTAROCK PARTNERS LP · CIK 0001631014 · Form 13F-HR · Accession 0001104659-26-097527
Reported Equity Holdings (USD)
$4.2bn
8 positions · mainly 13F (+ Non-US where noted)
Shown (≥1%)
6
13F combined (8 → 8) · 2 under 1% hidden
Largest weights: Amazon.com, Inc. 32.2%, TransDigm Group 27.5%, Microsoft Corporation 20.5%. Sorted by USD value.
Reported Equity Holdings USD
2 names under 1% hidden (still included in Reported Equity Holdings). Weights vs full book — visible weights may sum to under 100%.
| # | Issuer | Ticker / listing | CCY | Value (USD) | Weight | Source | As of | Notes |
|---|---|---|---|---|---|---|---|---|
| 1 | Amazon.com, Inc. |
AMZN · Nasdaq | USD | $1,365.7m | 32.2% | 13F | 13F — 30 Jun 2026 | COMM |
| 2 | TransDigm Group |
TDG · NYSE | USD | $1,166.5m | 27.5% | 13F | 13F — 30 Jun 2026 | COMM |
| 3 | Microsoft Corporation |
MSFT · Nasdaq | USD | $870.8m | 20.5% | 13F | 13F — 30 Jun 2026 | COMM |
| 4 | Mastercard Inc. |
MA · NYSE | USD | $392.7m | 9.3% | 13F | 13F — 30 Jun 2026 | COMM Class A common. |
| 5 | Visa Inc. |
V · NYSE | USD | $287.0m | 6.8% | 13F | 13F — 30 Jun 2026 | COMM Class A shares. |
| 6 | Moody's Corporation |
MCO · NYSE | USD | $137.1m | 3.2% | 13F | 13F — 30 Jun 2026 | COMM |
Methodology
- One book: All weights in USD. Reported Equity Holdings = Altarock Partners LP 13F-HR reported values (same-issuer/CUSIP rows aggregated). Schema X0202 whole USD.
- US 13F: Altarock Partners LP (CIK 0001631014) Form 13F-HR. Period end 30 Jun 2026, filed 17 Aug 2026. Manager: Mark Massey. Schema X0202 whole USD ($4.2bn).
- Enrichment: Book values and weights are from the SEC 13F-HR only (light enrich: tickers / display names). Altarock / Mark Massey is a highly concentrated US-listed equity compounder book. No separate Non-US regulator hunt in this pass.
- Filer note: Filer legal name ALTAROCK PARTNERS LP (formerly ALTAROCK PARTNERS LLC through mid-2024 filings). CIK 0001631014.
- Mixed as-of: US 13F as of period end 30 Jun 2026.
- Reported AUM: Firm / strategy AUM from the manager's site or Form ADV where cited on this page — separate from Reported Equity Holdings.
- Shares / Discretion / Vote columns omitted. Value shown as USD market value ($m, 1 decimal, e.g. $17,700.0m). Weight to 1 decimal.
- Table shows positions with weight ≥ 1.0% only; names under 1% are hidden but still included in Reported Equity Holdings (USD) and the weight denominator.
- Raw data: EDGAR 13F · portfolio_combined.json · holdings.json