Posner Brian S
Director | SEC CIK: 0001372455
Comprehensive Trading Performance Summary
The investment footprint of Posner Brian S as disclosed via official SEC Form 4 filings provides a critical window into professional capital allocation strategies. By tracking this specific portfolio, investors can analyze how this individual moves capital across different boards and sectors. High-conviction moves by key stakeholders often serve as leading indicators for future market performance, as they reflect the intimate operational knowledge and fiduciary confidence of those closest to the company's decision-making process. Monitoring these strategic accumulation or exit patterns helps bridge the gap between institutional boardrooms and the retail investment community.
| Filing Date | Trade Date | Ticker | Company Name | Industry | Relationship | Type | Price | Qty | Total, $ | Owned After | Change, % |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 2026-04-01 20:27 | 2026-03-30 | DYN | Dyne Therapeutics, Inc. | Pharmaceutical Preparations | Director | BUY | $17.08 | 2,000 | $34,160 | 15,500 | +14.8% |
| 2026-03-13 20:46 | 2026-03-11 | DYN | Dyne Therapeutics, Inc. | Pharmaceutical Preparations | Director | BUY | $19.35 | 2,000 | $38,700 | 13,500 | +17.4% |
| 2026-03-12 20:29 | 2026-03-11 | ACGL | ARCH CAPITAL GROUP LTD. | Fire, Marine & Casualty Insurance | Director | SELL | $17.12 | 3,000 | $51,345 | 2,000 | -60.0% |
| 2026-03-10 21:33 | 2026-03-06 | DYN | Dyne Therapeutics, Inc. | Pharmaceutical Preparations | Director | BUY | $15.06 | 3,000 | $45,180 | 11,500 | +35.3% |
| 2025-08-04 23:23 | 2025-08-01 | ACGL | ARCH CAPITAL GROUP LTD. | Fire, Marine & Casualty Insurance | Director | BUY | $17.34 | 1,000 | $17,338 | 5,000 | +25.0% |
| 2022-11-02 01:39 | 2022-10-28 | ACGL | ARCH CAPITAL GROUP LTD. | Fire, Marine & Casualty Insurance | Director | BUY | $17.60 | 2,000 | $35,200 | 4,000 | +100.0% |
| 2022-05-03 00:35 | 2022-04-29 | ACGL | ARCH CAPITAL GROUP LTD. | Fire, Marine & Casualty Insurance | Director | BUY | $19.23 | 2,000 | $38,450 | 2,000 | +100.0% |
| 2021-06-16 01:14 | 2021-06-14 | ACGL | ARCH CAPITAL GROUP LTD. | Fire, Marine & Casualty Insurance | Director | SELL | $25.24 | 4,000 | $100,971 | 2,000 | -66.7% |
| 2021-06-08 02:02 | 2021-06-04 | BIIB | BIOGEN INC. | Biological Products, (No Diagnostic Substances) | Director | SELL | $274.17 | 360 | $98,701 | 7,400 | -4.6% |
| 2020-05-15 21:12 | 2020-05-13 | ACGL | ARCH CAPITAL GROUP LTD. | Fire, Marine & Casualty Insurance | Director | BUY | $22.16 | 1,000 | $22,159 | 103,801 | +1.0% |
| 2020-05-08 23:57 | 2020-05-06 | ACGL | ARCH CAPITAL GROUP LTD. | Fire, Marine & Casualty Insurance | Director | BUY | $23.72 | 1,000 | $23,718 | 92,685 | +1.1% |
| 2019-12-04 01:58 | 2019-12-02 | BIIB | BIOGEN INC. | Biological Products, (No Diagnostic Substances) | Director | SELL | $292.35 | 1,055 | $308,429 | 6,995 | -13.1% |
| 2018-11-30 00:52 | 2018-11-28 | ACGL | ARCH CAPITAL GROUP LTD. | Fire, Marine & Casualty Insurance | Director | BUY | $25.05 | 1,000 | $25,051 | 85,127 | +1.2% |
| 2018-11-06 23:00 | 2018-11-05 | ACGL | ARCH CAPITAL GROUP LTD. | Fire, Marine & Casualty Insurance | Director | BUY | $22.45 | 2,500 | $56,124 | 2,500 | +100.0% |
| 2018-05-04 23:05 | 2018-05-03 | ACGL | ARCH CAPITAL GROUP LTD. | Fire, Marine & Casualty Insurance | Director | BUY | $78.63 | 3,000 | $235,876 | 25,439 | +13.4% |
| 2017-08-10 23:50 | 2017-08-09 | BIVV | N/A | Other | Director | BUY | $59.19 | 1,000 | $59,190 | 6,693 | +17.6% |
| 2017-06-12 23:29 | 2017-06-09 | BIIB | BIOGEN INC. | Biological Products, (No Diagnostic Substances) | Director | SELL | $256.31 | 1,084 | $277,840 | 6,330 | -14.6% |
| 2017-05-25 00:03 | 2017-05-24 | BIVV | N/A | Other | Director | BUY | $53.86 | 2,000 | $107,724 | 5,693 | +54.2% |
| 2016-11-22 00:05 | 2016-11-18 | ACGL | ARCH CAPITAL GROUP LTD. | Fire, Marine & Casualty Insurance | Director | BUY | $21.88 | 6,000 | $131,271 | 6,000 | +100.0% |
| 2015-06-23 23:14 | 2015-06-22 | BIIB | BIOGEN INC. | Biological Products, (No Diagnostic Substances) | Director | SELL | $415.00 | 470 | $195,050 | 5,275 | -8.2% |
| 2015-06-17 01:54 | 2015-06-15 | BIIB | BIOGEN INC. | Biological Products, (No Diagnostic Substances) | Director | SELL | $386.64 | 400 | $154,656 | 5,745 | -6.5% |
| 2013-08-20 16:00 | 2013-08-19 | ACGL | ARCH CAPITAL GROUP LTD. | Fire, Marine & Casualty Insurance | Director | BUY | $23.58 | 2,500 | $58,947 | 7,500 | +50.0% |
| 2013-08-06 00:23 | 2013-08-02 | ACGL | ARCH CAPITAL GROUP LTD. | Fire, Marine & Casualty Insurance | Director | BUY | $25.25 | 5,000 | $126,231 | 5,000 | +100.0% |
| 2013-06-13 23:23 | 2013-06-11 | BIIB | BIOGEN INC. | Biological Products, (No Diagnostic Substances) | Director | SELL | $219.62 | 2,020 | $443,632 | 8,130 | -19.9% |
| 2013-03-19 22:15 | 2013-03-18 | BIIB | BIOGEN INC. | Biological Products, (No Diagnostic Substances) | Director | SELL | $174.81 | 4,500 | $786,645 | 10,150 | -30.7% |
| 2012-11-21 00:39 | 2012-11-19 | BGMD | N/A | Other | Director | BUY | $1.17 | 10,000 | $11,650 | 20,000 | +100.0% |
| 2012-06-11 18:22 | 2012-06-07 | BIIB | BIOGEN INC. | Biological Products, (No Diagnostic Substances) | Director | OPT+S | $135.00 | 2,500 | $337,500 | 12,630 | 0.0% |
| 2012-06-05 22:41 | 2012-06-04 | BIIB | BIOGEN INC. | Biological Products, (No Diagnostic Substances) | Director | OPT+S | $126.45 | 2,400 | $303,480 | 12,630 | 0.0% |
| 2012-05-24 04:17 | 2012-05-22 | BGMD | N/A | Other | Director | BUY | $4.04 | 10,000 | $40,400 | 10,000 | +100.0% |
| 2011-08-31 18:44 | 2011-08-29 | BIIB | BIOGEN INC. | Biological Products, (No Diagnostic Substances) | Director | OPT+S | $92.53 | 15,000 | $1,387,895 | 12,630 | 0.0% |
| 2011-05-27 22:15 | 2011-05-25 | BIIB | BIOGEN INC. | Biological Products, (No Diagnostic Substances) | Director | OPT+S | $94.09 | 25,975 | $2,444,027 | 9,730 | 0.0% |
| 2006-10-11 19:06 | 2006-10-11 | SCD | LMP CAPITAL & INCOME FUND INC. | Other | Officer - Officer of the Adviser | BUY | $17.95 | 5,000 | $89,750 | 5,000 | +100.0% |
Tracking Multi-Role Insiders: Posner Brian S
High-level stakeholders like Posner Brian S, whether acting as directors, officers, or 10% owners, often possess unique cross-sector insights. Monitoring a specific CIK like 0001372455 allows investors to identify recurring patterns of trading success across various industries. When a large 10% shareholder or a key beneficial owner moves capital, it often signals a strategic shift in institutional or private conviction.
SEC Transparency for Key Stakeholders
Every market move made by Posner Brian S is a matter of public record under federal law. By aggregating Form 4 filings, we provide transparency into the portfolios of major players who hold significant influence. Following the money of those with a 10% stake or executive power helps bridge the information gap between the boardroom and the retail investor.
UNDERSTANDING THE DATA
FILING DATE: The date and time when the transaction was reported to the SEC. This is when the public first receives the information.
TRADE DATE: The actual day the insider executed the purchase or sale in the market.
INDUSTRY: The specific market sector the company operates in. Useful for identifying broader institutional capital flows across sectors.
OWNED AFTER: The total number of shares held by the insider following the transaction. This highlights the insider's remaining conviction in the company.
CHANGE %: The percentage increase or decrease of the insider's total position. Large percentage changes often carry more weight than the dollar amount alone.
TRADE TYPES DEFINITIONS
BUY: An open market purchase. Typically indicates an insider's belief that the stock is undervalued or poised for growth.
SELL: An open market sale. While often used for diversification or liquidity, large or unexpected sales can be a warning signal.
OPT+S (OPTION EXERCISE & SALE): This occurs when an insider exercises their stock options and sells them immediately. Often part of a structured compensation plan.