Brian S Posner
CIK 1372455 · View on SEC EDGAR ↗
Insider
First SEC filing: June 9, 2026 · Latest: June 9, 2026
On this page
Insider at
Insider transactions
7 buys (P)
3 sells (S)
Net:
$130,250
+ 62 non-open-market transactions below
Avg return of open purchases vs now:
53.3%
last 12 months, based on the transactions shown below
Price change vs current quote, split-adjusted for corporate actions since the filing — not benchmarked, not annualized, not size-weighted
62 other filings hidden
| Date | Ticker | Code | Shares | Price | Value | Owned after | Δ own | A/D | vs now |
|---|---|---|---|---|---|---|---|---|---|
| June 8, 2026 | DYN | P | 2,000 | $16.94 | $33,880 | 24,500 Direct | +8.89% | Acquired | 55.9% (price as of 2026-08-19) |
| June 3, 2026 | DYN | P | 2,500 | $17.48 | $43,700 | 22,500 Direct | +12.50% | Acquired | 51.1% (price as of 2026-08-19) |
| June 3, 2026 | ACGLN | S | 3,000 | $19.66 | $58,980 | 0 Direct | -100.00% | Disposed | -17.5% (price as of 2026-08-19) |
| May 26, 2026 | DYN | P | 2,000 | $18.21 | $36,420 | 20,000 Direct | +11.11% | Acquired | 45.0% (price as of 2026-08-19) |
| May 20, 2026 | DYN | P | 2,500 | $17.12 | $42,800 | 18,000 Direct | +16.13% | Acquired | 54.3% (price as of 2026-08-19) |
| May 11, 2026 | ACGLN | S | 2,000 | $17.14 | $34,280 | 0 Direct | -100.00% | Disposed | -5.4% (price as of 2026-08-19) |
| March 30, 2026 | DYN | P | 2,000 | $17.08 | $34,160 | 15,500 Direct | +14.81% | Acquired | 54.6% (price as of 2026-08-19) |
| March 11, 2026 | DYN | P | 2,000 | $19.35 | $38,700 | 13,500 Direct | +17.39% | Acquired | 36.5% (price as of 2026-08-19) |
| March 11, 2026 | ACGLN | S | 3,000 | $17.11 | $51,330 | 2,000 Direct | -60.00% | Disposed | -5.3% (price as of 2026-08-19) |
| March 6, 2026 | DYN | P | 3,000 | $15.06 | $45,180 | 11,500 Direct | +35.29% | Acquired | 75.4% (price as of 2026-08-19) |
| April 29, 2022 | ACGLN | P | 2,000 | $19.23 | $38,460 | 2,000 Direct | — | Acquired | -15.7% (price as of 2026-08-19) |
| June 14, 2021 | ACGLN | S | 4,000 | $25.24 | $100,960 | 2,000 Direct | -66.67% | Disposed | -35.8% (price as of 2026-08-19) |
| June 4, 2021 | BIIB | S 10b5-1 | 360 | $274.17 | $98,701 | 7,400 Direct | -4.64% | Disposed | -20.2% (price as of 2026-08-19) |
| May 13, 2020 | ACGLN | P | 1,000 | $22.16 | $22,160 | 103,801 Direct | +0.97% | Acquired | -26.9% (price as of 2026-08-19) |
| May 6, 2020 | ACGLN | P | 1,000 | $23.72 | $23,720 | 92,685 Direct | +1.09% | Acquired | -31.7% (price as of 2026-08-19) |
| Dec. 2, 2019 | BIIB | S 10b5-1 | 1,055 | $292.35 | $308,429 | 6,995 Direct | -13.11% | Disposed | -25.2% (price as of 2026-08-19) |
| Nov. 28, 2018 | ACGLN | P | 500 | $28.24 | $14,120 | 85,127 Direct | +0.59% | Acquired | -42.6% (price as of 2026-08-19) |
| Nov. 28, 2018 | ACGLN | P | 500 | $21.86 | $10,930 | 3,000 Direct | +20.00% | Acquired | -25.8% (price as of 2026-08-19) |
| Nov. 5, 2018 | ACGLN | P | 2,500 | $22.45 | $56,125 | 2,500 Direct | — | Acquired | -27.8% (price as of 2026-08-19) |
| May 3, 2018 | ACGLN | P | 1,000 | $77.38 | $77,380 | 25,439 Direct | +4.09% | Acquired | -79.1% (price as of 2026-08-19) |
| May 3, 2018 | ACGLN | P | 2,000 | $79.25 | $158,500 | 24,439 Direct | +8.91% | Acquired | -79.5% (price as of 2026-08-19) |
| June 9, 2017 | BIIB | S 10b5-1 | 1,084 | $256.31 | $277,840 | 6,330 Direct | -14.62% | Disposed | -14.7% (price as of 2026-08-19) |
| Nov. 18, 2016 | ACGLN | P | 6,000 | $21.88 | $131,280 | 6,000 Direct | — | Acquired | -25.9% (price as of 2026-08-19) |
| June 22, 2015 | BIIB | S 10b5-1 | 470 | $415.00 | $195,050 | 5,275 Direct | -8.18% | Disposed | -47.3% (price as of 2026-08-19) |
| June 15, 2015 | BIIB | S 10b5-1 | 400 | $386.64 | $154,656 | 5,745 Direct | -6.51% | Disposed | -43.4% (price as of 2026-08-19) |
| June 20, 2014 | BIIB | S 10b5-1 | 605 | $315.00 | $190,575 | 6,000 Direct | -9.16% | Disposed | -30.6% (price as of 2026-08-19) |
| June 13, 2014 | BIIB | S 10b5-1 | 700 | $310.50 | $217,350 | 6,605 Direct | -9.58% | Disposed | -29.6% (price as of 2026-08-19) |
| March 31, 2014 | BIIB | S 10b5-1 | 2,500 | $296.11 | $740,275 | 6,435 Direct | -27.98% | Disposed | -26.1% (price as of 2026-08-19) |
| March 31, 2014 | BIIB | S 10b5-1 | 500 | $300.00 | $150,000 | 8,935 Direct | -5.30% | Disposed | -27.1% (price as of 2026-08-19) |
| Aug. 19, 2013 | ACGLN | P | 2,500 | $23.58 | $58,950 | 7,500 Direct | +50.00% | Acquired | -31.3% (price as of 2026-08-19) |
| Aug. 2, 2013 | ACGLN | P | 5,000 | $25.25 | $126,250 | 5,000 Direct | — | Acquired | -35.8% (price as of 2026-08-19) |
| June 11, 2013 | BIIB | S 10b5-1 | 2,020 | $219.62 | $443,632 | 8,130 Direct | -19.90% | Disposed | -0.4% (price as of 2026-08-19) |
| March 18, 2013 | BIIB | S 10b5-1 | 4,500 | $174.81 | $786,645 | 10,150 Direct | -30.72% | Disposed | 25.1% (price as of 2026-08-19) |
| June 7, 2012 | BIIB | S 10b5-1 | 2,500 | $135.00 | $337,500 | 12,630 Direct | -16.52% | Disposed | 62.0% (price as of 2026-08-19) |
| June 4, 2012 | BIIB | S 10b5-1 | 2,400 | $126.45 | $303,480 | 12,630 Direct | -15.97% | Disposed | 73.0% (price as of 2026-08-19) |
| Aug. 29, 2011 | BIIB | S 10b5-1 | 15,000 | $92.53 | $1,387,950 | 12,630 Direct | -54.29% | Disposed | 136.4% (price as of 2026-08-19) |
| May 25, 2011 | BIIB | S 10b5-1 | 13,170 | $94.43 | $1,243,643 | 9,730 Direct | -57.51% | Disposed | 131.6% (price as of 2026-08-19) |
| May 25, 2011 | BIIB | S 10b5-1 | 12,805 | $93.74 | $1,200,341 | 22,900 Direct | -35.86% | Disposed | 133.3% (price as of 2026-08-19) |
Showing latest 100 of 101 transactions
P = Open-market purchase · S = Sale · A = Grant/award · M = Option exercise · G = Gift · F = Tax withholding
Insider transactions are not a recommendation; sales are often driven by liquidity or tax reasons.
Derivative holdings (Form 4 Table II)
Options, RSUs and convertible securities reported on Form 4 Table II.
| Date | Ticker | Security | Underlying | Exercise price | Expiration | Shares | A/D |
|---|---|---|---|---|---|---|---|
| June 5, 2026 | DYN | Stock option (right to buy) | Common Stock (35,152) | $17.04 | June 4, 2036 | 35,152 | Acquired |
| Oct. 1, 2025 | DYN | Stock option (right to buy) | Common Stock (70,000) | $12.50 | Sept. 30, 2035 | 70,000 | Acquired |
| June 7, 2012 | BIIB | Stock Option (Right to Buy) | Common Stock (2,500) | $71.38 | July 22, 2018 | 2,500 | Disposed |
| June 4, 2012 | BIIB | Stock Option (Right to Buy) | Common Stock (2,400) | $71.38 | July 22, 2018 | 2,400 | Disposed |
| Aug. 29, 2011 | BIIB | Stock Option (Right to Buy) | Common Stock (15,000) | $71.38 | July 22, 2018 | 15,000 | Disposed |
| May 25, 2011 | BIIB | Stock Option (Right to Buy) | Common Stock (20,000) | $71.38 | July 22, 2018 | 20,000 | Disposed |
| May 25, 2011 | BIIB | Stock Option (Right to Buy) [F5] | Common Stock (5,975) | $53.43 | June 2, 2019 | 5,975 | Disposed |
| June 3, 2009 | BIIB | Stock Option (Right to Buy) [F1] | Common Stock (5,975) | $53.43 | June 2, 2019 | 5,975 | Acquired |
| July 23, 2008 | BIIB | Stock Option (right to buy) | Common Stock (35,000) | $71.38 | July 22, 2018 | 35,000 | Acquired |
| July 23, 2008 | BIIB | Stock Option (right to buy) | Common Stock (4,900) | $71.38 | July 22, 2018 | 4,900 | Acquired |
Exercise/conversion price is blank when not applicable (e.g. RSUs).
Initial ownership (Form 3) 3 holdings
Securities held when first becoming an insider, per SEC Form 3.