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David R Brennan

CIK 1609305 · last filed 2026-09-11

David R Brennan is a corporate insider who has filed 29 SEC Form 4 insider transactions across 1 company since 2015. The most recent filing shows the insider sold $3.1M of INSM on Sep 11, 2026. Across all open-market trades the lifetime net is −$2.8M, making them a net seller over the disclosed history. Current disclosed insider exposure totals $11.7M across reported positions. 11 SEC filings were submitted jointly with ALEXION PHARMACEUTICALS, 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.

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Disclosed Exposure

$11.72M

Companies

1

Total Filings

29

Lifetime Open-Market Net

-$2.80M

Filer Profile

Reported Address
C/O INSMED INCORPORATED
10 FINDERNE AVENUE
BRIDGEWATER, NJ 08807
Related Filers
ALEXION PHARMACEUTICALS, INC. — 11 joint filings, latest 2021-07-23
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
INSM Director 99,238 $118.06 $11.72M -$2.80M 17 2026-09-11

Recent Filings

29 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
2026-09-11 INSM Sell (S) −25,000 -$3.10M EDGAR
2026-09-10 INSM Notice (144) −25,000 -$3.10M EDGAR
2026-05-15 INSM Grant (A) +3,305 $0 EDGAR
2026-02-25 INSM Gift (G) −6,000 $0 EDGAR
2025-11-10 INSM Gift (G) — $0 EDGAR
2025-05-19 INSM Grant (A) +5,058 $0 EDGAR
2024-05-15 INSM Grant (A) +13,162 $0 EDGAR
2023-05-15 INSM Grant (A) +13,192 $0 EDGAR
2022-05-13 INSM Grant (A) +14,645 $0 EDGAR
2021-11-03 INSM Buy (P) +10,000 $301.5K EDGAR
Showing 1–10 of 29
Page 1 of 3
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.