John Cox

CIK 1498428 · CEO & President · last filed 2026-09-08

John Cox is a CEO & President who has filed 84 SEC Form 4 insider transactions across 5 companies since 2010. The most recent filing, for DYN, was dated Sep 8, 2026. Across all open-market trades the lifetime net is −$13.3M, making them a net seller over the disclosed history. Current disclosed insider exposure totals $14.5M across reported positions. 37 SEC filings were submitted jointly with BIOGEN INC.

"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.

Disclosed Exposure

$14.53M

Companies

Total Filings

Lifetime Open-Market Net

-$13.35M

Charts

Trading activity, where the exposure sits, and each trade against the stock price.

Filer Profile

Reported Address

C/O BIOVERATIV INC.
225 SECOND AVENUE
WALTHAM, MA 02451

Related Filers

BIOGEN INC. — 37 joint filings, latest 2016-04-05

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
DYN	CEO & President	375,507	$15.35	$5.76M	$1.39M	15	2026-09-08
Sigilon Therapeutics, Inc. (SGTX) Delisted	Director	342	$22.47	$7.7K	$0	5	2023-08-11
RGEN	Director	923	$182.09	$168.1K	-$4.07M	10	2020-03-26
Bioverativ Inc. (BIVV) Delisted	Chief Executive Officer	0	—	—	$0	9	2018-03-08
BIIB	EVP Pharmaceutical Oper & Tech	39,045	$220.24	$8.60M	-$10.66M	36	2016-04-05

Recent Filings

84 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
2026-09-08	DYN	Notice (144)	−5,658	-$106.8K	EDGAR
2026-09-08	DYN	Sell (S)	−5,658	-$106.8K	EDGAR
2026-08-17	DYN	Sell (S)	−4,986	-$131.0K	EDGAR
2026-08-13	DYN	Notice (144)	−4,986	-$131.0K	EDGAR
2026-06-17	DYN	Sell (S)	−2,683	-$49.2K	EDGAR
2026-06-16	DYN	Notice (144)	−2,683	-$49.2K	EDGAR
2026-05-14	DYN	Sell (S)	−3,311	-$60.8K	EDGAR
2026-05-13	DYN	Notice (144)	−3,311	-$60.8K	EDGAR
2026-03-06	DYN	Sell (S)	−2,732	-$40.7K	EDGAR
2026-03-05	DYN	Notice (144)	−2,732	-$40.7K	EDGAR

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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.