Dyne Therapeutics, Inc.
Dyne Therapeutics, Inc. (DYN) Stock Ownership
Institutional vs insider vs public ownership from 13F and float data — top holders, activity, and insider trades below.
SEC 13F · FMP · DYN · as of Sep 30, 2025
Ownership Breakdown
217
Institutional Holders
▲ 16 vs Q2
$1.97B
Total Inst. Value
▲ $746.55M vs Q2
165.31M
Shares Outstanding
freeFloat 79.85%
155.84M
13F Shares Held
▲ 27.22M vs Q2
Institutional ownership = 13F shares ÷ total outstanding. Insider % = 100 − free float. Public % = free float − institution %. Data: FMP /symbol-positions-summary + /shares-float + SEC EDGAR.
Top Institutional Holders
DYN largest shareholders · institutional ownership
Q3 2025 · SEC 13F
Showing top 10 holders
| Holder | Shares | % Owned | Weight | Value | Reported | Change |
|---|---|---|---|---|---|---|
JANUS HENDERSON GROUP PLC pharmaceutical preparations | 14.75M | 12.95% | 12.95% | $186.49B | Nov 14, 2025 | ▲ 5.31M |
VANGUARD GROUP INC pharmaceutical preparations | 9.76M | 8.57% | 8.57% | $123.47B | Nov 7, 2025 | ▲ 2.11M |
BLACKROCK, INC. pharmaceutical preparations | 9.63M | 8.46% | 8.46% | $121.88B | Nov 12, 2025 | ▲ 1.56M |
ATLAS VENTURE LIFE SCIENCE ADVISORS, LLC pharmaceutical preparations | 9.13M | 8.02% | 8.02% | $115.50B | Nov 13, 2025 | — held |
FCPM III SERVICES B.V. pharmaceutical preparations | 5.46M | 4.80% | 4.80% | $69.11B | Nov 14, 2025 | — held |
FMR LLC pharmaceutical preparations | 5.40M | 4.74% | 4.74% | $68.33B | Nov 13, 2025 | ▲ 108.5K |
STATE STREET CORP pharmaceutical preparations | 5.27M | 4.63% | 4.63% | $66.65B | Nov 14, 2025 | ▲ 1.91M |
SIREN, L.L.C. pharmaceutical preparations | 4.73M | 4.15% | 4.15% | $59.82B | Nov 13, 2025 | ▼ 107.3K |
TCG CROSSOVER MANAGEMENT, LLC pharmaceutical preparations | 4.62M | 4.05% | 4.05% | $58.38B | Nov 17, 2025 | ▲ 848.5K |
ADAGE CAPITAL PARTNERS GP, L.L.C. pharmaceutical preparations | 3.55M | 3.12% | 3.12% | $44.96B | Nov 14, 2025 | ▲ 363.0K |
Data from SEC Form 13F filings. Ownership bar normalised to largest holder. Change flags: isNew / isSoldOut / changeInSharesNumber (FMP extract-analytics/holder).
Institutional Activity
Q3 2025 vs prior quarter
Q3 2025
38
Increased
+36.56M shares2
New Positions
first time holders5
Decreased
−1.76M shares0
Sold Out
fully exitedNet shares change (top 50)
+34.80M
+36.56M / −1.76M
Net new holders
+35
2 new / 0 exited
Based on top 50 institutional holders by position size. Fields: isNew, isSoldOut, changeInSharesNumber (FMP extract-analytics/holder, limit=50).
Insider Buying vs Selling
DYN insider trading · insider activity
Source: SEC Form 4
Insiders have been primarily selling shares recently. Selling may be driven by pre-scheduled Rule 10b5-1 plans rather than negative sentiment.
3
Buy transactions
61
Sell transactions
0.05
Buy/Sell ratio
$2M
Total disposed
Recent Insider Transactions
Showing 10 most recent · Common Stock only
| Name · Role | Date | Type | Shares | Price | Value | After Trans. | Filing |
|---|---|---|---|---|---|---|---|
Posner Brian S director | Jun 3, 2026 | Purchase | 2,500 | $17.48 | $43.7K | 22.5K | Form 4 ↗ |
Posner Brian S director | May 26, 2026 | Purchase | 2,000 | $18.21 | $36.4K | 20.0K | Form 4 ↗ |
Posner Brian S director | May 20, 2026 | Purchase | 2,500 | $17.12 | $42.8K | 18.0K | Form 4 ↗ |
Friedl-Naderer Johanna Chief Commercial Officer | May 13, 2026 | Sale | 228 | $18.36 | $4.2K | 154.4K | Form 4 ↗ |
Kerr Douglas Chief Medical Officer | May 13, 2026 | Sale | 1,564 | $18.36 | $28.7K | 170.0K | Form 4 ↗ |
Lucera Erick Chief Financial Officer | May 13, 2026 | Sale | 1,448 | $18.36 | $26.6K | 123.9K | Form 4 ↗ |
Cox John CEO & President | May 13, 2026 | Sale | 3,311 | $18.36 | $60.8K | 370.8K | Form 4 ↗ |
Rhodes Jason P director | May 4, 2026 | Sale | 6,241 | $18.00 | $112.3K | 4.93M | Form 4 ↗ |
Rhodes Jason P director | May 5, 2026 | Sale | 6,081 | $18.03 | $109.6K | 4.93M | Form 4 ↗ |
Rhodes Jason P director | May 6, 2026 | Sale | 43,621 | $18.18 | $793.0K | 4.88M | Form 4 ↗ |
Source: /insider-trading/search (FMP stable). Buy/Sell direction: acquisitionOrDisposition A=Buy, D=Sell. RSU vesting (M-Exempt) excluded from sentiment bar. All data from SEC EDGAR public filings.
About institutional & insider ownership
Dyne Therapeutics, Inc. (DYN) is primarily owned by institutional investors, who hold approximately 94.3% of total shares outstanding. Company insiders own approximately 20.15%, while retail and public investors account for the remaining 0.00%.
The largest institutional shareholder of Dyne Therapeutics, Inc. is JANUS HENDERSON GROUP PLC, holding approximately 14.75 million shares — equal to 12.95% of outstanding shares — as of September 30, 2025.
A total of 217 institutional investors currently hold DYN stock, with a combined institutional value of approximately $1.97 billion as of the most recent 13F filing period.
Frequently asked questions
DYN ownershipDyne Therapeutics, Inc. (DYN) is primarily owned by institutional investors, who hold approximately 94.3% of shares. The largest shareholder is JANUS HENDERSON GROUP PLC with a 12.95% stake. Company insiders hold 20.15%. Data sourced from SEC Form 13F as of September 30, 2025.