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James Topper Insider Profile
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James Topper, Director at Sierra Oncology, holds 6.83M shares in NewAmsterdam Pharma Company (Ticker: NAMS), holds 5.93M shares in Phathom Pharmaceuticals (Ticker: PHAT), holds 0.00 shares in Alpine Immune Sciences (Ticker: ALPN). Most recently, James Topper Bought ― shares of NewAmsterdam Pharma Company on Aug 13, 2025 for an estimated value of $11.29K.
Profitable Transactions
8 out of 13 Profitable Transactions
Average Return
+55.50%
Average return per transaction
Time Frame
Compare to
Insider Holdings
Insider Roles
Roles that James Topper holds in companies
Most Profitable Insider Trade
The most profitable trade made by James Topper
James Topper's Trading History
Sierra Oncology
Feb 16, 2017
―
Informative Buy
8.00M
―
Alpine Immune Sciences
May 20, 2024
―
Uninformative Sell
―
$0.00
AnaptysBio
Nov 18, 2020
Director, Ten Percent Owner
Uninformative Buy
―
$20.00M
Allena Pharmaceuticals
―
―
―
―
Aptinyx
Jun 26, 2018
―
Uninformative Buy
―
$306.25K
Entasis Therapeutics Holdings
Oct 02, 2018
―
Uninformative Buy
―
$2.96M
Phathom Pharmaceuticals
Jun 05, 2025
Director, Ten Percent Owner
Uninformative Buy
―
$73.81M
NewAmsterdam Pharma Company
Aug 13, 2025
Director
Informative Buy
11.29K
$167.07M
Portola Pharma
May 28, 2013
―
Uninformative Buy
―
$25.76M
Amicus
―
Director
―
$26.90M
La Jolla Pharma
Feb 26, 2009
―
Informative Sell
341.42K
$0.00
List of latest transactions for each holding click on a transaction to see James Topper's performance on stock
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James Topper insider profile FAQ
What is the percentage of profitable transactions made by James Topper?
The percentage of profitable transactions made by James Topper is 62%.
What is the average return per transaction made by James Topper?
The average return per transaction made by James Topper is 55.50%.
What stocks does James Topper hold?
James Topper holds: SRRA, ALPN, ANAB, ALNAQ, APTX, ETTX, PHAT, NAMS, PTLA, FOLD, LJPC stocks.
What was James Topper’s latest transaction?
James Topper latest transaction was an Informative Buy of $11.29K.
What was James Topper's most profitable transaction?
James Topper’s most profitable transaction was an Informative Buy of PHAT stock on May 13, 2025. The return on the trade was 259.80%.
What is James Topper's role in Sierra Oncology?
James Topper's role in Sierra Oncology is Director.
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