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Buy Day today: Good (62) Broad market participation · no major macro event
MASS

908 Devices Inc

Healthcare · Medical Devices · —

11.00$ +10.7% vs. previous close Closing price · As of: Sep 17, 2026

Ownership

Ownership Structure

Who owns 908 Devices Inc (MASS)? This page shows the largest institutions and funds, the ownership structure and the latest insider transactions. 67.9% of the shares are freely tradable; institutional investors hold 90.0%.

Institutional ownership ?Share of the stock held by institutional investors (funds, banks, insurers) according to regulatory filings. 90.0%
Insiders ?Share of the stock held by the executives, founders and major shareholders of the company itself. 9.0%
Float ?Share of stock freely tradable on the market — not locked up in the hands of founders, insiders, or major shareholders. 67.9%
Short % of float ?Shares sold short as a percentage of the freely tradable float — high values signal many bets on falling prices. 13.2%
Shares Outstanding ?Total number of shares issued. Price times share count gives market cap. 41Mio.

Largest Shareholders

Institutions

Institutions MASS
Name Stake (%) Shares Change (%) Date
First Light Asset Management, LLC 15.20 6,282,804 +3.5 06/30/2026
Awm Investment Company Inc 12.58 5,199,924 +0.0 03/31/2026
ARK Investment Management LLC 4.71 1,946,685 -2.0 03/31/2026
Arnhold & S. Bleichroeder Advisers, LLC 4.50 1,859,970 +131.5 06/30/2026
BlackRock Inc 4.28 1,767,316 -1.9 03/31/2026
Needham Investment Management, LLC 3.00 1,240,000 +61.0 03/31/2026
Vanguard Capital Management, LLC 2.71 1,119,236 +0.0 03/31/2026

Funds

Funds MASS
Name Stake (%) Shares Change (%) Date
ARK Genomic Revolution ETF 4.88 2,018,660 -0.3 08/31/2026
ARK Genomic Revolution 4.63 1,914,776 +4.0 06/30/2026
Needham Aggressive Growth Retail 3.38 1,397,650 +47.1 06/30/2026

Largest reported positions according to regulatory filings; stake as a percentage of shares outstanding, change versus the previous filing. Source: fundamentals data.

Insider holdings

Insider holdings MASS
Person Role Shares Value As of Type
AWM Investment Company, Inc. 10% Owner 4,779,773 52,577,503 $ Aug 21, 2026 indirect
Brown Christopher D. Director 775,559 8,531,149 $ Sep 2, 2026 direct
Knopp Kevin J. President and CEO 555,968 6,115,648 $ Aug 17, 2026 direct
Griffith Joseph H. IV Chief Financial Officer 121,497 1,336,467 $ Aug 25, 2026 direct
Vann Brandi C Director 5,192 57,112 $ Aug 1, 2026 direct

Holdings as of each person's most recent SEC Form 4 filing — excluding options and RSUs, which are not shares yet. Holdings may have changed between two filings.

Insiders

Insider Transactions

Insider Transactions
Date Person Role Type Shares Price Value
Sep 2, 2026 Brown Christopher D. Director Sell 30,000 10.58 317,400
Aug 25, 2026 Griffith Joseph H. IV Chief Financial Officer Sell 11,459 10.95 125,476
Aug 21, 2026 AWM Investment Company, Inc. 10% Owner Sell 41,578 10.61 441,159
Aug 20, 2026 AWM Investment Company, Inc. 10% Owner Sell 8,422 10.52 88,638
Aug 17, 2026 Knopp Kevin J. President and CEO Sell 20,000 10.35 207,000
Aug 13, 2026 Knopp Kevin J. President and CEO Sell 7,622 10.06 76,677
Aug 12, 2026 Knopp Kevin J. President and CEO Sell 2,747 10.07 27,662
Aug 11, 2026 Brown Christopher D. Director Sell 8,358 9.23 77,144
Aug 11, 2026 Knopp Kevin J. President and CEO Sell 30,170 10.16 306,527
Aug 11, 2026 Knopp Kevin J. President and CEO Sell 115,748 9.83 1,137,803
Aug 10, 2026 Brown Christopher D. Director Sell 9,442 9.03 85,261
Aug 10, 2026 Knopp Kevin J. President and CEO Sell 348 9.06 3,153
Aug 5, 2026 Brown Christopher D. Director Sell 20,000 8.49 169,800
Aug 4, 2026 AWM Investment Company, Inc. 10% Owner Sell 50,000 8.36 417,765
Aug 1, 2026 Vann Brandi C Director Other 5,192

Reportable transactions by officers and major shareholders from SEC Form 4 filings. "Other" includes things like stock grants and option exercises without a buy/sell character. View all insider transactions →

Data as of: September 17, 2026 · Source: fundamental data & SEC filings (annual and quarterly reports, 10-K/10-Q)

Note: pure fact-based analysis, not investment advice and not a solicitation to buy or sell. All figures without guarantee.

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