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sellWeak cluster of 510b5-1 plan

John Cox sold $131k of DYN

CEO & President at Dyne Therapeutics, Inc.. 4,986 shares at an average of $26.28, traded Aug 13, 2026, filed Aug 17, 2026.

Warning score
31
Value
$131k
4,986 shares
Holdings after
363,165
-1% from before
From 52-week low
+117%
low $11.97, close $25.96
From 52-week high
-3%
high $26.71, as of Aug 13, 2026

Score components

  • Role
    CEO
    +25
  • Trade size
    $131k at market
    +11
  • Share of holdings sold
    Sold 1.4% of holdings
    0
  • Cluster
    5 insiders selling within 14 days
    +15
  • 10b5-1 plan
    Pre-scheduled under a 10b5-1 plan
    -20

What happened after comparable sells

Same side and tier, against the S&P 500, at 1, 3 and 6 months. Shown to Pro users; the whole table is on the backtest page.

Price around the trade, and since

From a quarter before the trade to today. The arrow is the trade, the circle the day the filing reached EDGAR, which is the first day anyone outside could act; the dotted line is the S&P 500 rebased to that day's close.

DYNOct 9, 2026 · close 16.64
Since filing Aug 17, 2026: -36.4%SPY +1.0% · excess -37.4%

Daily candles, adjusted for splits and dividends. Green arrows are insider buys, red are sells, sized by value; the dashed line is the close on the filing day, the dotted line SPY rebased to it.Charts by TradingView Lightweight Charts™

Rows in this filing

Every transaction in Form 4 0001498428-26-000004, as filed. Open on EDGAR

DateTransactionSharesPriceValueHoldings afterFiled
Aug 13, 2026SOpen-market sale
Common Stock10b5-1
-4,986$26.28$131k363,165Aug 17, 2026

Related signals

Other insiders at Dyne Therapeutics, Inc. and this insider’s other filings.

ScoreCompanyInsiderValueHoldingsFiled
32Weak
DYNbuy
Dyne Therapeutics, Inc.
Brian S Posner
director
$40k
2,500 shares
+10%
30Weak
DYNsell 310b5-1
Dyne Therapeutics, Inc.
John Cox
CEO & President
$107k
5,658 shares
-2%
20Weak
DYNsell 310b5-1
Dyne Therapeutics, Inc.
Douglas Kerr
Chief Medical Officer
$116k
5,035 shares
-3%
15Weak
DYNsell 310b5-1
Dyne Therapeutics, Inc.
Johanna Friedl-Naderer
Chief Commercial Officer
$25k
1,085 shares
-1%
55Moderate
DYNsell 510b5-1
Dyne Therapeutics, Inc.
Jason P Rhodes
director
$65M
2,586,928 shares
-64%
23Weak
DYNsell 510b5-1
Dyne Therapeutics, Inc.
Erick Lucera
Chief Financial Officer
$47k
1,797 shares
-1%
16Weak
DYNsell 510b5-1
Dyne Therapeutics, Inc.
Douglas Kerr
Chief Medical Officer
$41k
1,556 shares
-1%
10Weak
DYNsell 510b5-1
Dyne Therapeutics, Inc.
Johanna Friedl-Naderer
Chief Commercial Officer
$5,939
226 shares
-0%
20Weak
DYNsell10b5-1
Dyne Therapeutics, Inc.
Dirk Kersten
director
$6.7M
261,460 shares
-7%
40Moderate
DYNsell 310b5-1
Dyne Therapeutics, Inc.
Jason P Rhodes
director
$18M
777,451 shares
-17%

Not investment advice. Scores and forward returns are decision support built from public SEC filings and past prices; they describe what happened after comparable filings, not what will happen after this one. Do your own research and size your risk.

John Cox sold $131k of DYN | InsiderTell