William Seybold - Net Worth and Insider Trading
William Seybold Net Worth
The estimated net worth of William Seybold is at least $2 Million dollars as of 2026-09-11. William Seybold is the of Generation Bio Co and owns about 383,764 shares of Generation Bio Co (GBIO) stock worth over $2 Million. Details can be seen in William Seybold's Latest Holdings Summary section.
Disclaimer: The insider information is derived from SEC filings. The estimated net worth is based on the final shares held after open market or private purchases and sales of common stock with a transaction code of "P" or "S" on Form 4, assuming that William Seybold has not made any transactions after 2020-06-16 and currently still holds the listed stock(s). Please note that this estimate may not reflect the actual net worth.
Transaction Summary of William Seybold
William Seybold Insider Ownership Reports
Based on ownership reports from SEC filings, as the reporting owner, William Seybold owns 6 companies in total, including Generation Bio Co (GBIO) , Nexvet Biopharma PLC (NVET) , and Playa Hotels & Resorts NV (PLYA) among others .
Click here to see the complete history of William Seybold’s form 4 insider trades.
Insider Ownership Summary of William Seybold
| Ticker | Company | Transaction Date | Type of Owner |
|---|---|---|---|
| GBIO | Generation Bio Co | 2020-06-16 | 10 percent owner & other: Member of Group Owning 10% |
| NVET | Nexvet Biopharma PLC | 2017-07-31 | 10 percent owner & other: Member of Group Owning 10% |
| PLYA | Playa Hotels & Resorts NV | 2017-03-11 | 10 percent owner & other: Member of Group Owning 10% |
 | | 2017-06-16 | 10 percent owner & other: Member of Group Owning 10% |
| | 2022-12-07 | other: Member of a Group Owning 10% |
| | 2025-08-06 | other: Member of a Group Owning 10% |
William Seybold Latest Holdings Summary
William Seybold currently owns a total of 1 stock. William Seybold owns 383,764 shares of Generation Bio Co (GBIO) as of June 16, 2020, with a value of $2 Million.
Latest Holdings of William Seybold
| Ticker | Company | Latest Transaction Date | Shares Owned | Current Price ($) | Current Value ($) |
|---|---|---|---|---|---|
| GBIO | Generation Bio Co | 2020-06-16 | 383,764 | 5.34 | 2,049,300 |
Holding Weightings of William Seybold
William Seybold Form 4 Trading Tracker
According to the SEC Form 4 filings, William Seybold has made a total of 0 transactions in Generation Bio Co (GBIO) over the past 5 years. The most-recent trade in Generation Bio Co is the acquisition of 40,000 shares on June 16, 2020, which cost William Seybold around $8 Million.
Insider Trading History of William Seybold
* The information on this page (including Insider Trading Shares, Share Changes, Cost, etc.) is sourced exclusively from Form 4 filings and does not incorporate any data from 13F or 13D/G filings. As a result, it may differ from the values shown on the Guru page.
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William Seybold Trading Performance
GuruFocus tracks the stock performance after each of William Seybold's buying transactions within different timeframes. To be detailed, the average return of stocks after 3 months bought by William Seybold is 48.56%. GuruFocus also compares William Seybold's trading performance to market benchmark return within the same time period. The performance of stocks bought by William Seybold within 3 months outperforms 1 times out of 1 transactions in total compared to the return of S&P 500 within the same period.
You can select different timeframes to see how William Seybold's insider trading performs compared to the benchmark.
Performance of William Seybold
Average Return
Outperforming Transactions
| 1 Month | 3 Months | 6 Months | 1 Year | 2 Years | 3 Years | |
|---|---|---|---|---|---|---|
| Return(%) | -5.42 | | | | | |
| Relative Return to S&P 500(%) | -8.33 | | | | | |
William Seybold Ownership Network
Ownership Network List of William Seybold
Ownership Network Relation of William Seybold
William Seybold Owned Company Details
What does Generation Bio Co do?
Who are the key executives at Generation Bio Co?
William Seybold is the 10 percent owner & other: Member of Group Owning 10% of Generation Bio Co. Other key executives at Generation Bio Co include CHIEF FINANCIAL OFFICER Kevin John Conway , CHIEF OPERATING OFFICER Antoinette Paone , and INTERIM CEO AND PRESIDENT Yalonda Howze .
Generation Bio Co (GBIO) Insider Trades Summary
In summary, during the past 3 months, insiders sold 0 shares of Generation Bio Co (GBIO) in total and bought 0 shares, with a net sale of 0 shares. During the past 18 months, 0 shares of Generation Bio Co (GBIO) were sold and 0 shares were bought by its insiders, resulting in a net sale of 0 shares.
Generation Bio Co (GBIO)'s detailed insider trading history can be found in Insider Trading Tracker table.
Generation Bio Co Insider Transactions
William Seybold Mailing Address
Above is the net worth, insider trading, and ownership report for William Seybold. Based on the public information released on the U.S. Securities and Exchange Commission (SEC) website, William Seybold's mailing address is: San Francisco Ca 94111.
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