---
title: Insmed CEO William Lewis Has Sold $96M in Career INSM Stock — CMO Flammer at $74M Career
type: news
slug: insmed-ceo-lewis-96m-career-cmo-flammer-74m-5-insiders-sell-insm-2026
canonical_url: https://13finsight.com/news/insmed-ceo-lewis-96m-career-cmo-flammer-74m-5-insiders-sell-insm-2026
published_at: 2026-02-28T21:13:02.820Z
updated_at: 2026-02-28T21:13:03.766Z
author: Alex Rivera
author_title: Breaking News Editor
author_url: https://13finsight.com/authors/alex-rivera
word_count: 487
locale: en
source: 13F Insight
---

# Insmed CEO William Lewis Has Sold $96M in Career INSM Stock — CMO Flammer at $74M Career

> Five Insmed insiders sold $11.5M in INSM stock, led by CEO Lewis ($4.7M, $96.1M career) and CMO Flammer ($4.7M, $74M career). CFO Bonstein adds $43.1M in career sales.

Five Insmed insiders sold a combined $11.51 million in INSM stock, with CEO William Lewis and Chief Medical Officer Martina Flammer each selling approximately $4.7 million. What makes Insmed's insider selling remarkable is the cumulative career context — the CEO has sold $96.1 million, the CMO $74 million, and the CFO $43.1 million. Five Insiders, Deep Career Selling Insider Title Recent Transactions Recent Value Career Sales Shares After William Lewis Chairman & CEO 14 $4.69M $96.1M 303,911 Martina Flammer, M.D. Chief Medical Officer 10 $4.72M $74.0M 83,111 Sara Bonstein Chief Financial Officer 3 $0.81M $43.1M 80,506 Roger Adsett Chief Operating Officer 3 $0.75M $15.2M 107,601 Michael Smith Chief Legal Officer 3 $0.55M $24.7M 57,037 Total: 5 insiders, 33 transactions $11.51M $253.1M $253 Million in Combined Career Sales The aggregate career total is the real story: these five insiders have sold a combined $253.1 million in Insmed stock. For a biotech company with a ~$12 billion market cap, that represents substantial founder and executive monetization. CEO Lewis: $96.1M Career — Nearly $100M William Lewis is approaching the $100 million career selling milestone. His 14 transactions in this round yielded $4.69M, and he retains 303,911 shares (~$21M). The CEO has now sold roughly 4.6x the value of his remaining position — a significant tilt toward cash over equity. CMO Flammer: $74M — The Doctor Who Sells CMO Martina Flammer's $74 million in career sales is exceptional for a Chief Medical Officer. She oversees Insmed's clinical programs, including the company's key drug Arikayce for lung infections. Her 10 transactions for $4.72M leave her with 83,111 shares (~$5.8M) — meaning she's sold roughly 13x her current position value over her career. CFO Bonstein: $43.1M — Quiet Giant CFO Sara Bonstein has sold $43.1 million in career INSM stock — a remarkable total for a finance chief. Her $810K sale in this round is modest relative to her history. She retains 80,506 shares (~$5.6M), meaning she's sold 7.7x her remaining position. The Biotech Monetization Machine Insmed develops treatments for serious lung diseases, with Arikayce (amikacin liposome inhalation suspension) as its commercial product and brensocatib as a promising pipeline candidate. The company's market cap of ~$12 billion reflects investor optimism about its drug pipeline. But the insider selling tells another story: CEO: $96.1M career — approaching nine figures in sales CMO: $74.0M career — the person who runs clinical trials has sold $74M CFO: $43.1M career — the finance chief has monetized aggressively CLO: $24.7M career — even the legal officer has sold nearly $25M COO: $15.2M career — every C-suite member selling in the millions For INSM investors, the $253M in combined career sales from five insiders is a clear signal that the leadership team has been consistently taking money off the table through Insmed's appreciation. The question isn't whether the science is real — it's whether the insiders' $253M in monetized gains already reflects the best-case scenario for the company's drugs.

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Source: 13F Insight — https://13finsight.com/news/insmed-ceo-lewis-96m-career-cmo-flammer-74m-5-insiders-sell-insm-2026
Author: Alex Rivera — https://13finsight.com/authors/alex-rivera
Last updated: 2026-02-28T21:13:03.766Z