Bruce Booth
CIK 1451612 · last filed 2026-07-02
"Disclosed insider exposure" sums this person's most-recently-reported share counts across each company they're an insider in, multiplied by the current underlying price. It is not net worth — it misses retail holdings, private investments, real estate, index funds, and any company where the person isn't an SEC-reporting insider. For informational purposes only.
Charts
Trading activity, where the exposure sits, and each trade against the stock price.
KYMR price and trades
Daily close with each Form 4 filing on this company marked: green = open-market buy, red = open-market sale, purple = grants, exercises, gifts and other non-market transactions. Marker size scales with the dollar value.
Shares held
Shares owned after each reported transaction on this company (direct holdings as reported).
Open-market buying and selling
by monthDollar value of open-market purchases (code P, up) and sales (code S, down) across all companies, by filing month. Grants, exercises and gifts are excluded.
Exposure by company
latestMost recently reported shares × current price. Faded bars (*) have had no filing in 3 years, so the person may no longer hold them. Click a bar to chart that company.
Filer Profile
SUITE 320
WALTHAM, MA 02451
Holdings By Company
| Symbol | Role | Shares | Price | Disclosed Exposure | Lifetime OM Net | Filings | Latest Filed |
|---|---|---|---|---|---|---|---|
| KYMR | Director | 475,805 | $104.78 | $49.85M | -$263.36M | 27 | 2026-07-02 |
| SION | Director | 2,360,156 | $3.89 | $9.18M | -$21.01M | 8 | 2026-06-18 |
| Vigil Neuroscience, Inc. (VIGL) Delisted | Director | 0 | $8.05 | $0 | $7.49M | 11 | 2025-08-05 |
| Tectonic Therapeutic, Inc. (AVRO) Delisted | Director | 463,941 | $16.80 | $7.79M | $15.00M | 7 | 2023-06-08 |
| Dianthus Therapeutics, Inc. /DE/ (MGTA) Delisted | Director | 257,320 | $11.19 | $2.88M | $9.75M | 7 | 2022-06-30 |
| Cogent Biosciences, Inc. (UMRX) Delisted | Director | 3,184,446 | — | — | $1.13M | 12 | 2020-07-06 |
| Viridian Therapeutics, Inc.\DE (MGEN) Delisted | Director | 209,505 | — | — | $3.00M | 5 | 2018-06-28 |
| Larimar Therapeutics, Inc. (ZFGN) Delisted | Director | 386,502 | — | — | $0 | 7 | 2018-01-05 |
Recent Filings · Page 2 of 9
86 filings| Filed | Symbol | Action | Net Shares | Net $ | Link |
|---|---|---|---|---|---|
| 2026-04-14 | KYMR | Notice (144) | −24,000 | -$2.12M | EDGAR |
| 2026-03-04 | KYMR | Sell (S) | −81,866 | -$7.38M | EDGAR |
| 2025-12-12 | KYMR | Sell (S) | −236,588 | -$21.70M | EDGAR |
| 2025-10-21 | SION | Sell (S) | −88,878 | -$3.04M | EDGAR |
| 2025-10-20 | SION | Sell (S) | −286,369 | -$9.25M | EDGAR |
| 2025-10-15 | SION | Sell (S) | −194,932 | -$5.94M | EDGAR |
| 2025-10-07 | SION | Sell (S) | −49,546 | -$1.49M | EDGAR |
| 2025-10-01 | SION | Sell (S) | −78,693 | -$2.37M | EDGAR |
| 2025-08-05 | Vigil Neuroscience, Inc. (VIGL) Delisted | Disp (D) | −5,841,874 | $0 | EDGAR |
| 2025-06-26 | KYMR | Grant (A) | — | $0 | EDGAR |
Notice (144 / 144/A): Form 144 is a notice of intent to sell restricted/control stock under Rule 144, filed before the sale; 144/A is an amendment. Many notices are pre-scheduled under Rule 10b5-1 plans. A Form 4 with code S typically follows within a few days when the planned sale executes; missing follow-up Form 4s suggest the notice was cancelled or modified.