WILLIAM K HEIDEN
CIK 1214939 · President & CEO · last filed 2026-06-11
WILLIAM K HEIDEN is a President & CEO who has filed 53 SEC Form 4 insider transactions across 4 companies since 2009. The most recent filing, for ATRA, was dated Jun 11, 2026. Across all open-market trades the lifetime net is −$7.0M, making them a net seller over the disclosed history. Current disclosed insider exposure totals $810.3K across reported positions.
"Disclosed insider exposure" sums this person's most-recently-reported share counts across each company they're an insider in, multiplied by the current underlying price. It is not net worth — it misses retail holdings, private investments, real estate, index funds, and any company where the person isn't an SEC-reporting insider. For informational purposes only.
$810.3K
4
53
-$6.99M
Holdings By Company
| Symbol | Role | Shares | Price | Disclosed Exposure | Lifetime OM Net | Filings | Latest Filed |
|---|---|---|---|---|---|---|---|
| ATRA | Director | 34,188 | $10.41 | $355.9K | $25.3K | 14 | 2026-06-11 |
| MGNX | Director | 114,750 | $3.96 | $454.4K | $150.5K | 7 | 2026-05-20 |
| AMAG PHARMACEUTICALS, INC. (AMAG) Delisted | President & CEO | 424,612 | — | — | -$7.16M | 30 | 2020-03-04 |
| GTC BIOTHERAPEUTICS INC (GTCB) Delisted | Director | — | — | — | $0 | 1 | 2009-10-05 |
Recent Filings
53 filings| Filed | Symbol | Action | Net Shares | Net $ | Link |
|---|---|---|---|---|---|
| 2026-06-11 | ATRA | Grant (A) | +12,000 | $0 | EDGAR |
| 2026-05-20 | MGNX | Mixed | +3,750 | $0 | EDGAR |
| 2025-08-21 | MGNX | Buy (P) | +100,000 | $150.5K | EDGAR |
| 2025-06-12 | ATRA | Grant (A) | +7,828 | $0 | EDGAR |
| 2025-05-22 | MGNX | Mixed | +6,500 | $0 | EDGAR |
| 2024-05-23 | MGNX | Grant (A) | — | $0 | EDGAR |
| 2024-05-22 | MGNX | Exer (M) | +4,500 | $0 | EDGAR |
| 2024-04-02 | ATRA | Grant (A) | +150,000 | $0 | EDGAR |
| 2023-11-14 | ATRA | Buy (P) | +100,000 | $25.3K | EDGAR |
| 2023-06-02 | MGNX | Grant (A) | — | $0 | EDGAR |