Mark Massey

Net selling

Altarock Partners Lp — managed by Mark Massey; US equity positions disclosed quarterly via SEC 13F

Data as of 2026-06-30 (filed 2026-08-17) · Source: SEC EDGAR

Portfolio value$4.24B (+3%)

Holdings8

Top holdingAmazon.Com Inc

Below band0

New

Added

Exited

By what price implies: 3 demand a demanding growth rate, 0 modest.

SEC 13F · latest filing

Holdings

Security	Value	Valuation	Holders	Shares	Weight	Signal
Amazon.Com IncAMZN	$1.37B	—	39	5,729,972	32.2%	Core 8q
Transdigm Group IncTDG	$1.17B	—	7	875,755	27.5%	Core 8q
Microsoft CorpMSFT	$870.8M	—	43	2,334,482	20.5%	Big new
Mastercard Inc-Class AMA	$392.7M	—	21	764,507	9.3%	Big new
Visa Inc-Class A ShrsV	$287.0M	—	32	836,470	6.8%	Big new
Moodys CorpMCO	$137.1M	—	20	302,624	3.2%	—
Alphabet Inc-Cl AGOOGL	$15.0M	—	41	41,994	0.4%	—
Hilton WorldwideHLT	$5.0M	—	5	15,202	0.1%	—

Amazon.Com IncAMZNCore 8q
Value$1.37BValuation—Holders39Weight32.2%
Transdigm Group IncTDGCore 8q
Value$1.17BValuation—Holders7Weight27.5%
Microsoft CorpMSFTBig new
Value$870.8MValuation—Holders43Weight20.5%
Mastercard Inc-Class AMABig new
Value$392.7MValuation—Holders21Weight9.3%
Visa Inc-Class A ShrsVBig new
Value$287.0MValuation—Holders32Weight6.8%
Moodys CorpMCO—
Value$137.1MValuation—Holders20Weight3.2%
Alphabet Inc-Cl AGOOGL—
Value$15.0MValuation—Holders41Weight0.4%
Hilton WorldwideHLT—
Value$5.0MValuation—Holders5Weight0.1%

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About this investor

Portfolio overview

Altarock Partners Lp's most recent 13F filing, for the quarter ended 2026-06-30, reports 8 positions worth $4.24B. The top 5 holdings represent 96% of that value, a concentrated portfolio.

The single largest position is Amazon.Com Inc at 32.2% of the portfolio, followed by Transdigm Group Inc at 27.5% and Microsoft Corp at 20.5%.

Against the prior quarter, Mark Massey opened 0 new positions, exited 0, added to 3, and trimmed 5.

Across all 8 quarters on file, Amazon.Com Inc has appeared in every filing, as has Transdigm Group Inc. Amazon.Com Inc currently ranks first by value.

A 13F is filed roughly 45 days after quarter-end and covers only long positions in US-listed equities, so it is a lagging and partial view of the portfolio. Source: SEC EDGAR.

Mark Massey has no positions in the strike zone right now. Browse the whole market by value band

Sources· SEC EDGAR 13F as of 2026-06-30 · filed 2026-08-17

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