Insider transactions

Briggs Morrison

CIK 1654430 · President, Head of R&D · last filed 2026-06-26

"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
$1.31M
Companies
8
Total Filings
64
Lifetime Open-Market Net
-$27.68M

Charts

Trading activity, where the exposure sits, and each trade against the stock price.

SNDX 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 month

Dollar 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

latest
OfficerDirector10% owner* stale (no filing in 3 yrs)

Most 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

Reported Address
C/O SYNDAX PHARMACEUTICALS, INC.
400 TOTTEN POND ROAD, SUITE 110
WALTHAM, MA 02451
Profile details as reported on the filer's SEC submissions — for individual insiders the address is often in care of the issuer. Related filers are identified from jointly filed SEC submissions and shared reported addresses. View filings on SEC EDGAR.

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
ARVN Director 111,548 $7.45 $831.0K -$2.18M 14 2026-06-26
CRSP Director — $51.47 — $0 2 2026-06-09
HOWL Director — $1.04 — $0 5 2025-06-13
Carisma Therapeutics Inc. (CARM) Delisted Director — $0.00 — $0 2 2024-06-27
Repare Therapeutics Inc. (RPTX) Delisted Director 4,800 $2.65 $12.7K $96.0K 5 2024-06-20
SNDX Director 34,836 $13.69 $476.9K -$25.70M 27 2024-02-09
Codiak BioSciences, Inc. (CDAK) Delisted Director 4,761 $0.06 $271 $100.0K 2 2021-02-17
NXTC Director — $5.71 — $0 2 2020-06-15

Recent Filings · Page 5 of 7

64 filings
Insider activity across all companies, newest first. Form 4 rows are post-trade confirmations (buys, sells, grants, exercises). Notice (144) rows are pre-trade notices of intent to sell restricted or control stock under Rule 144 — they may not all execute. Compare adjacent dates to see which notices became actual sales.
Filed Symbol Action Net Shares Net $ Link
2021-12-20 SNDX Mixed — -$319.9K EDGAR
2021-09-21 SNDX Mixed — -$904.8K EDGAR
2021-06-10 ARVN Grant (A) — $0 EDGAR
2021-05-14 Repare Therapeutics Inc. (RPTX) Delisted Grant (A) — $0 EDGAR
2021-05-04 HOWL Grant (A) — $0 EDGAR
2021-02-17 Codiak BioSciences, Inc. (CDAK) Delisted Buy (P) +4,761 $100.0K EDGAR
2021-02-10 SNDX Mixed — -$469.3K EDGAR
2021-02-05 SNDX Mixed +1,771 $21.3K EDGAR
2020-11-12 SNDX Mixed — -$1.03M EDGAR
2020-10-15 Codiak BioSciences, Inc. (CDAK) Delisted Grant (A) — $0 EDGAR
Showing 41–50 of 64
Page 5 of 7
Form 4 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.
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.