Topper James N

SEC CIK: 0001341382

SEC filings (opens in a new tab)

In the past year, 1 open-market purchase filing worth $12.0M and no sales.

Current role at each company

PHAT Phathom Pharmaceuticals, Inc.Director, 10% Owneras of May 21, 2026
MBX MBX Biosciences, Inc.10% Owneras of Sep 30, 2025
HLVX HilleVax, Inc.10% Owneras of Sep 17, 2025
NAMS NewAmsterdam Pharma Co N.V.Directoras of Sep 17, 2025
ALPN Alpine Immune Sciences, Inc.Directoras of May 20, 2024

Show 2 more companies

ARQT Arcutis Biotherapeutics, Inc.10% Owneras of Oct 26, 2023
ANAB Anaptysbio, IncDirector, 10% Owneras of Jan 10, 2023

Open-market trades in the past year

Open-market purchases (P) and sales (S) filed in the last 365 days, not counting derivative securities or duplicate filings. Values leave out price outliers.

Bought: $12.0M; 1 filing
Sold: –; 0 filings
Net: +$12.0M; Bought minus sold
Companies: 1; With open-market trades

Trades

Every Form 4 that lists Topper James N as a reporting owner, including filings made jointly with others, grouped by company. Each row adds up one type of transaction in one filing. Only open-market purchases (P) and sales (S) are shown by default.

Transaction type

Role

Minimum value (USD)

Filed from

Filed to

Filing delay at least (days)

Filing delay at most (days)

MBX MBX Biosciences, Inc.

10% Owner2 trades

Insider trades
Filed (ET)	Trade date	Filing delay	Insider	Transaction	Shares	Avg price	Value	Holding change	Flags
Sep 30, 2025 (view filing)4:59 PM ET	Sep 26	4 days	Heron Patrick J and 4 othersDirector, 10% Owner	PPurchase	+666.7K	$18.00	+$12.0M	+14.6%5.22M after
Sep 17, 2024 (view filing)8:11 PM ET	Sep 16	1 day	Topper James N and 3 others10% Owner	PPurchase	+625.0K	$16.00	+$10.0M	+15.9%4.55M after	Duplicate filing

NAMS NewAmsterdam Pharma Co N.V.

Director8 trades

Insider trades
Filed (ET)	Trade date	Filing delay	Insider	Transaction	Shares	Avg price	Value	Holding change	Flags
Sep 17, 2025 (view filing)	Sep 15	2 days	Topper James NDirector	PPurchase	+660	$23.70	+$15.6K	0.0%3.03M after
Sep 10, 2025 (view filing)	Sep 8	2 days	Topper James NDirector	PPurchase	+1.26K	$24.99	+$31.5K	0.0%3.03M after
Aug 13, 2025 (view filing)	Aug 11	2 days	Topper James NDirector	PPurchase	+471	$23.98	+$11.3K	0.0%3.03M after
Jun 26, 2025 (view filing)	Jun 24-25	2 days	Topper James NDirector	PPurchase	+3.78K	$18.37	+$69.5K	+0.1%3.03M after	2 lots
Jun 18, 2025 (view filing)	Jun 16	2 days	Topper James NDirector	PPurchase	+8.58K	$19.50	+$167.4K	+0.3%3.02M after
Mar 28, 2025 (view filing)	Mar 26	2 days	Topper James NDirector	PPurchase	+1.14K	$22.49	+$25.5K	0.0%3.01M after
Mar 6, 2025 (view filing)	Mar 4	2 days	Topper James NDirector	PPurchase	+4.00K	$21.02	+$84.2K	+0.1%3.01M after
Mar 28, 2024 (view filing)	Mar 26	2 days	Topper James NDirector	PPurchase	+8.43K	$21.50	+$181.2K	+0.3%3.01M after

PHAT Phathom Pharmaceuticals, Inc.

Director, 10% Owner3 trades

Insider trades
Filed (ET)	Trade date	Filing delay	Insider	Transaction	Shares	Avg price	Value	Holding change	Flags
May 23, 2025 (view filing)	May 21	2 days	Topper James NDirector	PPurchase	+3.78K	$3.86	+$14.6K	+6.8%59.4K after
May 15, 2025 (view filing)	May 13-14	2 days	Topper James NDirector	PPurchase	+7.42K	$3.30	+$24.5K	+15.4%55.6K after	2 lots
May 13, 2025 (view filing)	May 9-12	4 days	Topper James NDirector	PPurchase	+48.2K	$3.17	+$152.8K	New position48.2K after	3 lots

ALPN Alpine Immune Sciences, Inc.

Director2 trades

Insider trades
Filed (ET)	Trade date	Filing delay	Insider	Transaction	Shares	Avg price	Value	Holding change	Flags
Apr 29, 2024 (view filing)	Apr 25	4 days	Topper James NDirector	SSale	−19	$64.57	−$1.23K	0.0%2.83M after
Feb 15, 2022 (view filing)5:00 PM ET	Feb 11	4 days	Topper James N and 4 othersDirector, 10% Owner	PPurchase	+112.7K	$7.10	+$800.0K	+8.2%1.48M after

ARQT Arcutis Biotherapeutics, Inc.