ZeroStack ZSTK Insider Ownership

NASDAQ ZSTK
$4.84 +0.60 (+14.15%)
At close: Sep 29, 2026 · 4:00 PM EDT

Insider Holdings by Owner

10.61Mn Shares

Insider Ownership Statistics

as of 30 Sep, 2026
Insider Ownership
106.49%
▲+106.05% pp QoQ
Shares Held by Insiders
10.61Mn
filed for Sep 2026
▲+23,936.28% QoQ
Shares Outstanding
9.96Mn
9,961,000 shares
Direct Holdings
6.00Mn
Indirect: 4.61Mn
Net Shares Traded (QoQ)
+10.56Mn
net buying in Sep 2026
Insiders Holding Shares
14
with Form 4 holdings on file

Shares Owned by Insiders

Shares held % of outstanding
Latest —
Average ownership —
Peak ownership —

Shares Purchased/Sold by Insiders

Bought Sold
Latest quarter —
Net over range —
Buying quarters —

Insider Ownership Summary

Quarter ending 30 Sep, 2026

As of September 29, 2026, ZeroStack's top three insider holders are Daniel Reis-Faria (Ceo, 5.95Mn shares), Michael Heinrich (Executive Chairman, 4.61Mn shares), Juan Carlos Gomez Roa (Director, 34.04K shares).

Form 4 Holdings

Insiders Holding ZSTK

Insiders 14
Shares held 10.61Mn
Of outstanding 106.49%
# Insider Position Direct Indirect Total Share of Insiders Last Filed
1 Daniel Reis-Faria Ceo 5,954,743 0 5,954,743 56.1% 20 Jul, 2026
2 Michael Heinrich Executive Chairman 0 4,608,575 4,608,575 43.4% 20 Jul, 2026
3 Juan Carlos Gomez Roa Director 34,041 0 34,041 0.3% 21 Mar, 2023
4 Marc Mastronardi Director 2,667 0 2,667 0.0% 21 Mar, 2023
5 Beverley Richardson Director 2,500 0 2,500 0.0% 21 Mar, 2023
6 John Timothy Leslie Director 2,310 0 2,310 0.0% 21 Mar, 2023
7 Brandon Konigsberg Director 1,667 0 1,667 0.0% 21 Mar, 2023
8 Clifford Starke Ceo 388 0 388 0.0% 16 Dec, 2024
9 Sammy Dorf Executive Chairman 107 0 107 0.0% 16 Dec, 2024
10 Dany Vaiman Cfo 73 0 73 0.0% 15 Nov, 2023
11 Edward Woo Director 58 0 58 0.0% 16 Dec, 2024
12 Kevin Taylor Chairman 53 0 53 0.0% 14 Nov, 2023
13 Thomas Solomon Director 15 0 15 0.0% 15 Nov, 2023
14 Harold Wolkin Director 11 0 11 0.0% 11 Sep, 2024

Each row is that insider’s most recently reported position, from Form 4 filings over the last 60 months — which is why this total does not tie to the quarterly series above, where a quarter counts only the insiders who filed in it. Shares held through a fund or institutional portfolio are counted on the institutional ownership page instead.

Form 4 Filings

53 Insider Transactions

Source SEC Form 4
Latest quarter Sep 2026
Download Data
Date Insider Position Transaction Shares Price Value Shares Held After Ownership
19 Aug, 2026 Rudy Rong President Disposed S 1,000 $7.57 $7.57K 0 Direct
20 Jul, 2026 Michael Heinrich Executive Chairman Acquired P 4,608,575 $0.75 $3.48Mn 4,608,575 Indirect
20 Jul, 2026 Daniel Reis-Faria Ceo Acquired X 5,954,743 $0.00 $595 5,954,743 Direct
20 Jul, 2026 Dany Vaiman Cfo Acquired A 250,000 $0.00 $0 250,000 Direct
20 Jul, 2026 Michael Heinrich Executive Chairman Acquired A 500,000 $0.00 $0 500,000 Direct
20 Jul, 2026 Daniel Reis-Faria Ceo Acquired A 500,000 $0.00 $0 500,000 Direct
20 Jul, 2026 Daniel Reis-Faria Ceo Disposed X 5,954,743 $25.19 $150.00Mn 0 Direct
05 May, 2026 Laurence Zeifman Director Acquired A 28,000 $0.00 $0 28,000 Direct
05 May, 2026 Edward Woo Director Acquired A 35,000 $0.00 $0 35,000 Direct
05 May, 2026 Manfred Leventhal Director Acquired A 35,000 $0.00 $0 35,000 Direct
31 Mar, 2026 Michael Heinrich Executive Chairman Disposed J 4,902,220 — — 0 Indirect
19 Dec, 2025 Daniel Reis-Faria Ceo Acquired A 471,208 $0.00 $0 471,208 Direct
19 Dec, 2025 Michael Heinrich Executive Chairman Acquired A 471,208 $0.00 $0 471,208 Direct
19 Dec, 2025 Dany Vaiman Cfo Acquired A 235,604 $0.00 $0 235,604 Direct
23 Oct, 2025 Michael Heinrich Executive Chairman Acquired X 4,902,220 — — 4,902,220 Indirect
22 Oct, 2025 Michael John Brown Director Acquired A 7,468 $0.00 $0 94,421 Direct
09 Oct, 2025 Daniel Reis-Faria Ceo Acquired P 5,954,743 $25.19 $150.00Mn 5,954,743 Direct
30 Jun, 2025 Manfred Leventhal Director Disposed D 5,000 — — 0 Direct
30 Jun, 2025 Harold Wolkin Director Disposed D 30,000 — — 0 Direct
30 Jun, 2025 Dany Vaiman Cfo Disposed D 342,888 — — 0 Direct