DYN Dyne Therapeutics, Inc.

NASDAQ
$18.21

Dyne Therapeutics, Inc. (DYN) Insider Activity

What the officers, directors and large holders did with their own shares. Only open-market purchases and sales count toward the totals — grants, option exercises and shares withheld for tax are compensation mechanics, not decisions, and they're listed separately below.

30D 90D 6M 1Y
Insider signal In line Selling ran in line with DYN's own trailing one-year pace, with 100% of sale value under a prearranged plan.
Cluster activity 0 buyers in the last 30 days 0 buyers in the last 90 days 6 sellers in the last 90 days
Insiders buying
1
7 transactions
Insiders selling
6
122 transactions
Purchases
$274.8K
16,000 shares
Sales
$168.6M
7,611,963 shares
Net activity
-$168.3M
purchases less sales

How much of that selling was preplanned? 100% planned / 0% discretionary

10b5-1 plan sales $168.5M 120 transactions · 7,604,601 shares
Discretionary sales $166.2K 2 transactions · 7,362 shares

Largest single sale: $34.0M.

Where they traded

Buy Sell Dot area is proportional to transaction value.

Last open-market purchase: June 8, 2026 , by Posner Brian S .

Recent open-market activity

Date Insider Role Action Shares Price Value Held after
Cox John CEO & President Sell 10b5-1 5,658 $18.88 $106.8K 357,507 −1.6% of holding
Kerr Douglas Chief Medical Officer Sell 10b5-1 1,290 $18.88 $24.4K 162,564 −0.8% of holding
Friedl-Naderer Johanna Chief Commercial Officer Sell 10b5-1 185 $18.88 $3.5K 152,897 −0.1% of holding
Kerr Douglas Chief Medical Officer Sell 10b5-1 3,745 $24.35 $91.2K 163,854 −2.2% of holding
Friedl-Naderer Johanna Chief Commercial Officer Sell 10b5-1 900 $24.35 $21.9K 153,082 −0.6% of holding
Rhodes Jason P 3 fills Director Sell 10b5-1 2,160,516 $25.00 $54.0M 2,441,454 −46.9% of holding
Rhodes Jason P 3 fills Director Sell 10b5-1 426,412 $26.20 $11.2M 3,801,128 −10.1% of holding
Cox John CEO & President Sell 10b5-1 4,986 $26.28 $131.0K 363,165 −1.4% of holding
Lucera Erick Chief Financial Officer Sell 10b5-1 1,797 $26.28 $47.2K 119,766 −1.5% of holding
Kerr Douglas Chief Medical Officer Sell 10b5-1 1,556 $26.28 $40.9K 167,599 −0.9% of holding
Friedl-Naderer Johanna Chief Commercial Officer Sell 10b5-1 226 $26.28 $5.9K 153,982 −0.1% of holding
Kersten Dirk 2 fills Director Sell 10b5-1 261,460 $25.51 $6.7M 3,592,184 −6.8% of holding
Rhodes Jason P 6 fills Director Sell 10b5-1 292,211 $23.26 $6.8M 4,099,069 −6.7% of holding
Rhodes Jason P Director Sell 5,000 $23.61 $118.1K 2,962 −62.8% of holding
Rhodes Jason P 3 fills Director Sell 10b5-1 480,240 $22.79 $10.9M 4,223,448 −10.2% of holding
Rhodes Jason P 3 fills Director Sell 10b5-1 195,427 $21.14 $4.1M 4,476,487 −4.2% of holding
Rhodes Jason P 3 fills Director Sell 10b5-1 309,268 $21.28 $6.6M 4,579,456 −6.3% of holding
Rhodes Jason P 3 fills Director Sell 10b5-1 24,100 $21.10 $508.5K 4,742,410 −0.5% of holding
Lucera Erick Chief Financial Officer Sell 2,362 $20.37 $48.1K 121,563 −1.9% of holding
Rhodes Jason P 3 fills Director Sell 10b5-1 95,900 $21.02 $2.0M 4,755,109 −2% of holding
Rhodes Jason P 3 fills Director Sell 10b5-1 147,760 $21.13 $3.1M 4,805,639 −3% of holding
Kersten Dirk 2 fills Director Sell 10b5-1 73,286 $21.05 $1.5M 3,849,913 −1.9% of holding
Kersten Dirk Director Sell 10b5-1 190,676 $20.57 $3.9M 3,921,542 −4.6% of holding
Kersten Dirk Director Sell 10b5-1 46,901 $20.07 $941.4K 4,112,218 −1.1% of holding
Kersten Dirk Director Sell 10b5-1 37,454 $20.14 $754.3K 4,159,119 −0.9% of holding
Cox John CEO & President Sell 10b5-1 2,683 $18.33 $49.2K 368,151 −0.7% of holding
Kerr Douglas Chief Medical Officer Sell 10b5-1 887 $18.33 $16.3K 169,155 −0.5% of holding
Friedl-Naderer Johanna Chief Commercial Officer Sell 10b5-1 145 $18.33 $2.7K 154,208 −0.1% of holding
Posner Brian S Director Buy 2,000 $16.94 $33.9K 24,500
Posner Brian S Director Buy 2,500 $17.48 $43.7K 22,500
Posner Brian S Director Buy 2,000 $18.21 $36.4K 20,000
Posner Brian S Director Buy 2,500 $17.12 $42.8K 18,000
Cox John CEO & President Sell 10b5-1 3,311 $18.36 $60.8K 370,834 −0.9% of holding
Kerr Douglas Chief Medical Officer Sell 10b5-1 1,564 $18.36 $28.7K 170,042 −0.9% of holding
Lucera Erick Chief Financial Officer Sell 10b5-1 1,448 $18.36 $26.6K 123,925 −1.2% of holding
Friedl-Naderer Johanna Chief Commercial Officer Sell 10b5-1 228 $18.36 $4.2K 154,353 −0.1% of holding
Rhodes Jason P 4 fills Director Sell 10b5-1 83,219 $18.18 $1.5M 4,883,494 −1.7% of holding
Rhodes Jason P 4 fills Director Sell 10b5-1 11,600 $18.03 $209.1K 4,927,115 −0.2% of holding
Rhodes Jason P 4 fills Director Sell 10b5-1 11,904 $18.00 $214.3K 4,933,196 −0.2% of holding
Rhodes Jason P 8 fills Director Sell 10b5-1 227,337 $18.38 $4.2M 4,939,489 −4.4% of holding
Rhodes Jason P 4 fills Director Sell 10b5-1 173,493 $18.15 $3.1M 5,058,604 −3.3% of holding
Rhodes Jason P 4 fills Director Sell 10b5-1 137,948 $18.48 $2.5M 5,149,547 −2.6% of holding
Rhodes Jason P 4 fills Director Sell 10b5-1 73,108 $19.19 $1.4M 5,221,857 −1.4% of holding
Rhodes Jason P 4 fills Director Sell 10b5-1 287,956 $19.68 $5.7M 5,260,179 −5.2% of holding
Kersten Dirk Director Sell 10b5-1 2,652 $20.00 $53.0K 4,196,573 −0.1% of holding
Rhodes Jason P 8 fills Director Sell 10b5-1 274,297 $19.52 $5.4M 5,412,651 −4.8% of holding
Kersten Dirk Director Sell 10b5-1 8,300 $20.01 $166.1K 4,199,225 −0.2% of holding
Rhodes Jason P 4 fills Director Sell 10b5-1 272,049 $20.06 $5.5M 5,554,904 −4.7% of holding
Kersten Dirk Director Sell 10b5-1 125,274 $20.07 $2.5M 4,207,525 −2.9% of holding
Kersten Dirk Director Sell 10b5-1 211,974 $20.29 $4.3M 4,332,799 −4.7% of holding
Kersten Dirk 2 fills Director Sell 10b5-1 17,773 $20.71 $368.1K 4,551,430 −0.4% of holding
Kersten Dirk Director Sell 10b5-1 81,840 $20.27 $1.7M 4,562,546 −1.8% of holding
Lucera Erick Chief Financial Officer Sell 10b5-1 5,727 $18.64 $106.8K 125,373 −4.4% of holding
Posner Brian S Director Buy 2,000 $17.08 $34.2K 15,500
Kersten Dirk Director Sell 10b5-1 129,672 $19.52 $2.5M 4,644,386 −2.7% of holding
Posner Brian S Director Buy 2,000 $19.35 $38.7K 13,500
Kersten Dirk 3 fills Director Sell 10b5-1 511,098 $19.57 $10.0M 5,275,674 −8.8% of holding
Kersten Dirk Director Sell 10b5-1 177,690 $17.72 $3.1M 5,285,156 −3.3% of holding
Posner Brian S Director Buy 3,000 $15.06 $45.2K 11,500
Cox John CEO & President Sell 10b5-1 2,732 $14.90 $40.7K 374,145 −0.7% of holding
Kerr Douglas Chief Medical Officer Sell 10b5-1 904 $14.90 $13.5K 171,606 −0.5% of holding
Friedl-Naderer Johanna Chief Commercial Officer Sell 10b5-1 148 $14.90 $2.2K 154,581 −0.1% of holding
Cox John CEO & President Sell 10b5-1 2,662 $20.72 $55.2K 196,877 −1.3% of holding
Kerr Douglas Chief Medical Officer Sell 10b5-1 880 $20.72 $18.2K 87,510 −1% of holding
Friedl-Naderer Johanna Chief Commercial Officer Sell 10b5-1 144 $20.72 $3.0K 94,729 −0.2% of holding

Form 4s are due within two business days of a transaction, so this is close to real time — unlike the quarterly 13F data on the Institutional tab. A single large sale often reflects a prearranged 10b5-1 plan rather than a fresh view, so read a pattern of sales rather than any one of them.