Heinrich Michael
Activist
First SEC filing: April 2, 2026 · Latest: April 2, 2026
Insider at
Insider transactions
1 buys (P)
0 sells (S)
Net: $3,456,431
Avg return of open purchases vs now: 542.7%
Price change vs current quote, split-adjusted for corporate actions since the filing — not benchmarked, not annualized, not size-weighted
| Date | Ticker | Code | Shares | Price | Value | Owned after | Δ own | A/D | vs now |
|---|---|---|---|---|---|---|---|---|---|
| July 20, 2026 | ZSTK | A | 500,000 | · | · | 500,000 Direct | · | Acquired | (price as of 2026-10-05) |
| July 20, 2026 | ZSTK | P | 4,608,575 | $0.75 | $3,456,431 | 4,608,575 Indirect | · | Acquired | 542.7% (price as of 2026-10-05) |
| March 31, 2026 | ZSTK | J | 4,902,220 | · | · | 0 Indirect | -100.00% | Disposed | (price as of 2026-10-05) |
| Dec. 19, 2025 | ZSTK | A | 471,208 | · | · | 471,208 Direct | · | Acquired | (price as of 2026-10-05) |
| Oct. 23, 2025 | ZSTK | X | 4,902,220 | · | · | 4,902,220 Indirect | · | Acquired | (price as of 2026-10-05) |
P = Open-market purchase · S = Sale · A = Grant/award · M = Option exercise · G = Gift · F = Tax withholding
Insider transactions are not a recommendation; sales are often driven by liquidity or tax reasons.
Derivative holdings (Form 4 Table II) Options, RSUs and convertible securities reported on Form 4 Table II.
| Date | Ticker | Security | Underlying | Exercise price | Expiration | Shares | A/D |
|---|---|---|---|---|---|---|---|
| July 20, 2026 | ZSTK | Employee Stock Option (Right to Buy) | Common Shares | $5.10 | May 5, 2036 | 500,000 | Acquired |
| March 31, 2026 | ZSTK | Convertible Promissory Note | Common Shares | $33.34 | Sept. 22, 2035 | 4,902,220 | Disposed |
| Dec. 19, 2025 | ZSTK | Director Stock Option (Right to Buy) | Common Shares | $7.31 | Dec. 18, 2035 | 471,208 | Acquired |
| Oct. 23, 2025 | ZSTK | Convertible Promissory Note | Common Shares | $33.34 | Sept. 22, 2035 | 4,902,220 | Acquired |
Exercise/conversion price is blank when not applicable (e.g. RSUs).