Insmed INSM Insider Ownership

Updated Oct 10, 2026

In the last 12 months, insiders at Insmed made open-market sales of $167.12 million (1.1Mn shares) and bought no shares on the open market.

• Counted by insider, open-market selling of INSM stock in the past 12 months came from 10 insiders, with no insider buying.
• The largest open-market sales of INSM in the past 12 months were by Roger Adsett (Chief Operating Officer), totaling $48.25 million (341.2K shares), most recently on August 10, 2026.
• The latest open-market trade on record is a sale of 25K shares for $3.1 million by David R. Brennan (Director) on September 9, 2026.
• Away from the open market, INSM insiders received 48.76K shares in stock awards, acquired 804.8K shares through option exercises and conversions and gave away 120.57K shares as gifts over the last 12 months.
• Business Quant data puts insider holdings in INSM at 1.67Mn shares across insiders' latest Form 4 filings, or 0.76% of the 218.28Mn shares outstanding; that total is down 1.75% from 1.7Mn shares at the end of Q2 2026 and down 16.73% from 2Mn shares at the end of Q3 2025.
• By type of ownership, INSM insiders hold 77.66% of their shares directly (1.29Mn shares) and 22.34% indirectly (372.17K shares).
• Business Quant counts 15 insiders with holdings in Insmed stock, among the officers, directors and 10% owners who have filed a Form 4 in the past two years.
• Insmed's top three insider holders by shares held are William Lewis (Chair and CEO, 492.98K shares), Melvin Sharoky (Director, 267.9K shares) and John Drayton Wise (Chief Commercial Officer, 133.01K shares).
• The largest insider, William Lewis, holds 29.59% of INSM's insider total.
• Over the trailing 12 months, 14 insiders reported transactions in INSM stock across 75 Form 4 filings.
• This summary of Insmed insider activity covers Form 4 filings through September 11, 2026.