Insider Trading & Ownership of Brian S. Posner

Location: Cambridge, MA
Summary: The estimated net worth of Brian S. Posner is at least $13,820,443 dollars as of 13 Mar 2026. Brian S. Posner is the Director of ARCH CAPITAL GROUP LTD. and owns shares of ARCH CAPITAL GROUP LTD. (ACGL) stock worth about $11.57M. Brian S. Posner is the Director of BIOGEN INC. and owns shares of BIOGEN INC. (BIIB) stock worth about $1.99M. Brian S. Posner is the Director of Dyne Therapeutics, Inc. and owns shares of Dyne Therapeutics, Inc. (DYN) stock worth about $261.2K.
Signature: /s/ Ron Caponigro, Attorney-in-Fact
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Ownership of Brian S. Posner

Symbol	Company	Relationship	Holdings Value	Past Year Net Change	Change %	Report Period
ACGL, ACGLO	ARCH CAPITAL GROUP LTD.	Director	$11,569,018	-$34,007	-0.29%	11 Mar 2026
BIIB	BIOGEN INC.	Director	$1,990,200			31 Dec 2022
DYN	Dyne Therapeutics, Inc.	Director	$261,225	+$83,880	+47%	11 Mar 2026

Sym	Company	Class	Transaction	%	Value $	* Price $	Shares	Shares After	Date	Ownership

* An asterisk sign (*) next to the price indicates that the price is likely invalid.