InsiderFlow

Brian S Posner

ACGL

Brian S Posner serves as director at Arch Capital Group Ltd. (ACGL). This page tracks their complete SEC Form 4 insider trading history including stock purchases and sales.

Total Buys

4 trades

$136.2K

Total Sells

3 trades

$249.7K

Net Position

Net Seller

$113.5K

Companies Traded

3

DYN, ACGL, BIIB

Active Period

Jun 2021 – Mar 2026

7 total trades

Most Recent

Buy DYN

Mar 10, 2026 · $45.2K

Brian S Posner's Insider Trading at Arch Capital Group Ltd. (ACGL)

Buys

3 · $91.0K

Sells

2 · $151.0K

Total Shares Bought

5,000

Total Shares Sold

6,000

ACGL Price Chart
Loading chart...
DateTypeSharesAvg PriceValueShares After
Aug 1, 2025Buy1,000$17.34$17.3K0
Oct 28, 2022Buy2,000$17.60$35.2K0
Apr 29, 2022Buy2,000$19.23$38.5K0
Sep 30, 2021Sell2,000$25.00$50.0K0
Jun 14, 2021Sell4,000$25.24$101.0K0

Brian S Posner's Insider Trading at Biogen Inc. (BIIB)

Buys

0 · $0.00

Sells

1 · $98.7K

Total Shares Bought

0

Total Shares Sold

360

BIIB Price Chart
Loading chart...
DateTypeSharesAvg PriceValueShares After
Jun 4, 2021Sell360$274.17$98.7K0

Brian S Posner's Insider Trading at Dyne Therapeutics, Inc. (DYN)

Buys

1 · $45.2K

Sells

0 · $0.00

Total Shares Bought

3,000

Total Shares Sold

0

DYN Price Chart
Loading chart...
DateTypeSharesAvg PriceValueShares After
Mar 10, 2026Buy3,000$15.06$45.2K11,500
Brian S Posner Insider Trading Activity | Arch Capital Group Ltd. | InsiderFlow