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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 $779.7K 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.

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Disclosed Exposure

$779.7K

Companies

4

Total Filings

53

Lifetime Open-Market Net

-$6.99M

Filer Profile

Reported Address
C/O AMAG PHARMACEUTICALS, INC.
1100 WINTER STREET
WALTHAM, MA 02451
Profile details as reported on the filer's SEC submissions — for individual insiders the address is often in care of the issuer. Related filers are identified from jointly filed SEC submissions and shared reported addresses. View filings on SEC EDGAR.

Holdings By Company

Latest on-record share count from this person's most recent non-derivative Form 4 transaction in each company. Disclosed exposure = shares × current underlying price.
Symbol Role Shares Price Disclosed Exposure Lifetime OM Net Filings Latest Filed
ATRA Director 34,188 $9.38 $320.7K $25.3K 14 2026-06-11
MGNX Director 114,750 $4.00 $459.0K $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
Insider activity across all companies, newest first. Form 4 rows are post-trade confirmations (buys, sells, grants, exercises). Notice (144) rows are pre-trade notices of intent to sell restricted or control stock under Rule 144 — they may not all execute. Compare adjacent dates to see which notices became actual sales.
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
Showing 1–10 of 53
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Form 4 codes: P = open-market purchase · S = open-market sale · A = grant/award · M = option exercise · F = tax withholding at vest · G = bona-fide gift · D = disposition to issuer · J = other (see filing footnote). Only P / S codes carry directional signal.
Notice (144 / 144/A): Form 144 is a notice of intent to sell restricted/control stock under Rule 144, filed before the sale; 144/A is an amendment. Many notices are pre-scheduled under Rule 10b5-1 plans. A Form 4 with code S typically follows within a few days when the planned sale executes; missing follow-up Form 4s suggest the notice was cancelled or modified.