Bruce Booth

CIK 1451612 · last filed 2026-04-24

Bruce Booth is a corporate insider who has filed 77 SEC Form 4 insider transactions across 8 companies since 2015. The most recent filing, for KYMR, was dated Apr 24, 2026. Across all open-market trades the lifetime net is −$112.3M, making them a net seller over the disclosed history. Current disclosed insider exposure totals $143.5M across reported positions.

"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.

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Disclosed Exposure

$143.47M

Companies

8

Total Filings

77

Lifetime Open-Market Net

-$112.33M

Holdings By Company

Latest on-record share count from this person's most recent non-derivative Form 4 transaction in each company. Disclosed exposure = shares × current underlying price.
Symbol Role Shares Price Disclosed Exposure Lifetime OM Net Filings Latest Filed
KYMR Director 680,844 $86.20 $58.69M -$127.69M 21 2026-04-24
SION Director 2,360,156 $35.92 $84.78M -$21.01M 7 2025-10-21
Vigil Neuroscience, Inc. (VIGL) Delisted Director 0 $8.05 $0 $7.49M 11 2025-08-05
Tectonic Therapeutic, Inc. (AVRO) Delisted Director 5,567,289 $16.80 $93.53M $15.00M 7 2023-06-08
Dianthus Therapeutics, Inc. /DE/ (MGTA) Delisted Director 4,117,125 $11.19 $46.09M $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 3,142,580 $3.00M 5 2018-06-28
Larimar Therapeutics, Inc. (ZFGN) Delisted Director 4,638,028 $0 7 2018-01-05

Recent Filings

77 filings
Form 4 transactions across all companies, newest first.
Filed Symbol Action Net Shares Net $ Link
2026-04-24 KYMR Mixed −100 -$454.6K EDGAR
2026-04-16 KYMR Mixed −3,135 -$764.4K 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
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Codes: P = open-market purchase · S = open-market sale · A = grant/award · M = option exercise · F = tax withholding at vest · G = bona-fide gift · D = disposition to issuer · J = other (see filing footnote). Only P / S codes carry directional signal.