Skip to content
Guess what? Valuesider just got better: smarter and more intuitive.
User

Mark Massey

AltaRock Partners

Mark Massey Amazon.com Inc stake

total: 19

AltaRock Partners AMZN trades

Total transactions:
17
New positions:
1
Added:
8
Reduced:
8
Held since:
2022 Q1
Held for:
17 quarters
Latest activity:
2026 Q1
According to 2026 Q1 report, Mark Massey holds 7,567,946 Amazon.com Inc (AMZN) shares with a market value of roughly $1.58B accounting for 38.20% of the overall portfolio. To date, the estimated cost basis is nearly $156.27 for "buy" trades and estimated average "sell" price is $157.08. AltaRock Partners first purchased AMZN in 2022 Q1, initially acquiring about 2.54M shares. Since the initial investment in Amazon.com Inc (AMZN), AltaRock Partners has made 16 more transactions.

How many AMZN shares does Mark Massey currently hold?

According to 2026 Q1 report, Mark Massey holds 7,567,946 shares of Amazon.com Inc (AMZN), valued at around $1.58B.

When did Mark Massey buy Amazon.com Inc (AMZN)?

Mark Massey first invested in Amazon.com Inc (AMZN) in 2022 Q1 at the reported quarter-end price of $163.00 per share.

What's the cost basis of AltaRock Partners's AMZN stake?

The estimated cost basis for Amazon.com Inc (AMZN) stake is around $156.27 per share. This represents their average reported price* across all buy transactions

Estimated cost basis*

Weighted AVG buy price:
$156.27
Weighted AVG sell price:
$157.08

Mark Massey's historical trades in Amazon.com Inc

17 results
Period % of
portfolio
Shares
held after*
Reported
price*
Value* % (shares)
of activity
% change
to portfolio
2026 Q1
38.20%
7,567,946
$208.27
$1,576,176,113
+3.46% (+253,412)
+1.28%
2025 Q4
33.10%
7,314,534
$230.82
$1,688,340,738
-3.22% (-243,719)
-1.03%
2025 Q3
30.34%
7,558,253
$219.57
$1,659,565,611
+20.43% (+1,282,347)
+5.15%
2025 Q2
25.14%
6,275,906
$219.39
$1,376,871,017
+20.63% (+1,073,491)
+4.3%
2025 Q1
19.90%
5,202,415
$190.26
$989,811,478
-1.44% (-75,905)
-0.29%
2024 Q4
23.42%
5,278,320
$219.39
$1,158,010,625
-2.30% (-124,000)
-0.54%
2024 Q3
19.83%
5,402,320
$186.33
$1,006,614,286
+30.82% (+1,272,860)
+4.67%
2024 Q2
16.43%
4,129,460
$193.25
$798,018,145
-1.78% (-75,000)
-0.31%
2024 Q1
16.30%
4,204,460
$180.38
$758,400,495
-5.19% (-230,174)
-0.93%
2023 Q4
15.03%
4,434,634
$151.94
$673,798,290
-3.60% (-165,600)
-0.63%
2023 Q3
14.65%
$127.12
-9.92% (-506,547)
2023 Q2
15.99%
$130.36
-12.93% (-758,170)
2023 Q1
16.59%
$103.29
+3.91% (+220,581)
2022 Q4
14.90%
$84.00
+71.35% (+2,350,336)
2022 Q3
12.19%
$113.00
+7.49% (+229,614)
2022 Q2
10.04%
$106.21
+20.41% (+519,500)
2022 Q1
10.58%
$163.00
new
* Shares, change to shares, sold shares, shares held after: split-adjusted.
* Reported price: this doesn't represent the actual buy or sell price. It is the split-adjusted price of the security as of the last day of the reported period.
If the security is completely sold out, we show the reported split-adjusted price prior to the actual period.
* Estimated cost basis: based on "Reported price*" (not earlier than 2013 Q2). Calculation starts from the latest "new buy" activity to the latest "close out" activity (if any).
* Value or Price: If the security is completely sold out, we show the reported value (or price) prior to the actual period.
* New buy or own: this means there is no earlier reporting (for us or in general). So we can't know if the actual purchase of the security happened at the reported period or earlier.