Prothena Corporation plc
US ˙ NasdaqGS ˙ IE00B91XRN20

Introduction

This page provides a comprehensive analysis of the known insider trading history of Tran Nguyen. Insiders are officers, directors, or significant investors in a company. It is illegal for insiders to make trades in their companies based on specific, non-public information. This does not mean it is illegal for them to make any trades in their own companies. However, they must report all trades to the SEC via a Form 4. Despite these restrictions, academic research suggests that insiders - in general - tend to outperform the market in their own companies.

Average Trade Profitability

The average trade profitability is the average return of all the open market purchases made by the insider in the last three years. To calculate this, we examine every open-market, unplanned purchase made by the insider, excluding all trades that were marked as part of a 10b5-1 trading plan. We then calculate the average performance of those trades over 3, 6, and 12 months, averaging each of those durations to generate a final performance metric for each trade. Finally, we average all of the performance metrics to calculate a performance metric for the insider. This list only includes insiders that have made at least three trades in the last two years.

If this insiders trade profitability is "N/A", then the insider either has not made any open-market purchases in the last three years, or the trades they’ve made are too recent to calculate a reliable performance metric.

Update Frequency: Daily

See the list of most profitable insider traders.

Companies with Reported Insider Positions

The SEC filings indicate Tran Nguyen has reported holdings or trades in the following companies:

Security Title Latest Reported Holdings
US:PRTA / Prothena Corporation plc Chief Strategy Officer and CFO 97,205
US:SRRA / Sierra Oncology Inc Director 30,000
US:SOMX / Somaxon Pharmaceuticals, Inc. SVP and CFO 0
How to Interpret the Charts

The following charts show the stock performance of securities subsequent to each open-market, non-planned trade made by Tran Nguyen. Non-planned trade are trades that were not made as part of a 10b5-1 trading plan. The stock performance is charted as cumulative percent change in share price. For example, if an insider trade was made on January 1, 2019, the chart will show the daily percent change of the security to the present day. If the share price were to go from $10 to $15 during this time, the cumulative percent change in share price would be 50%. A change in price from $10 to $20 would be 100%, and a change in price of $10 to $5 would be -50%.

Ultimately, we are trying to determine how closely the insider’s trades correlate to excess returns (positive or negative) in the share price in order to see if the insider is timing their trades to profit from insider information. Consider the situation where an insider was doing this. In this situation, we would expect either (a) positive returns after purchases, or (b) negative returns after sales. In the case of (a), the PURCHASE chart would show a series of upwardly sloping curves, indicating positive returns after each purchase transaction. In the case of (b), the SALE chart would show a series of downward sloping curves, indicating negative returns after each sale transaction.

However, this alone is not enough to draw conclusions. If, for example, the share price of the company was in a non-cyclical climb over many years, then we would expect all the post-purchase plots to be upwardly sloping. Likewise, non-cyclical declines over many years would result in downward sloping post-trade plots. Neither of these charts would suggest insider trading activity.

The strongest indicator would be a situation where the share price was extremely cyclical, and there were both positive signals in the PURCHASE chart and negative plots on the SALE chart. This situation would be highly suggestive of an insider that was timing trades to their financial advantage.

Insider Purchases PRTA / Prothena Corporation plc - Short Term Profit Analysis

In this section, we analyze the profitability of every unplanned, open-market insider purchase made in PRTA / Prothena Corporation plc. This analysis helps to understand if the insider consistently generates abnormal returns, and is worth following. This analysis is for one-year following each trade, and the results are theoretical.

The following table shows the most recent open market purchases that were not part of an automatic trading plan.

Trade Date Ticker Insider Reported
Shares
Reported
Price
Adjusted
Shares
Adjusted
Price
Cost Basis Days to
Max
Price at
Max
Max
Profit ($)
Max Return (%)
2017-03-09 PRTA Nguyen Tran 1,000 51.3172 1,000 51.3172 51,317 203 67.7500 16,433 32.02
2014-05-09 PRTA Nguyen Tran 2,200 19.6064 2,200 19.6064 43,134

Adjusted Price is the split-adjusted price. Adjusted Shares is the split-adjusted shares.

PRTA / Prothena Corporation plc Insider Trades
Insider Sales PRTA / Prothena Corporation plc - Short Term Loss Analysis

In this section, we analyze the short-term loss avoidance of every unplanned, open-market insider sale made in PRTA / Prothena Corporation plc. A consistent pattern of loss avoidance may suggest that future sale transactions may predict declines in price. This analysis is for one-year following each trade, and the results are theoretical.

The following table shows the most recent open market sales that were not part of an automatic trading plan.

Trade Date Ticker Insider Reported
Shares
Reported
Price
Adjusted
Shares
Adjusted
Price
Cost Basis Days to
Min
Price at
Min
Max Loss
Avoided ($)
Max Loss
Avoided (%)
There are no known unplanned open-market trades for this insider and security combination

Adjusted Price is the split-adjusted price. Adjusted Shares is the split-adjusted shares.

PRTA / Prothena Corporation plc Insider Trades
Insider Trading History

This table shows the complete list of insider trades made by Tran Nguyen as disclosed to the Securities Exchange Commission (SEC).

File Date Tran Date Form Ticker Security Code 10b5-1 Shares Remaining Shares Percent
Change
Share
Price
Tran
Value
Remaining
Value
2025-07-30 2025-07-28 4 PRTA PROTHENA CORP PUBLIC LTD CO
Ordinary Shares, par value $0.01 per share
A - Award 95,000 97,205 4,308.39
2025-02-14 2020-04-08 4 PRTA PROTHENA CORP PUBLIC LTD CO
Ordinary Shares, par value $0.01 per share
J - Other -995 2,205 -31.09
2023-05-17 2023-05-17 4 PRTA PROTHENA CORP PUBLIC LTD CO
Ordinary Shares, par value $0.01 per share
S - Sale X -100 3,200 -3.03 76.04 -7,604 243,328
2023-05-17 2023-05-17 4 PRTA PROTHENA CORP PUBLIC LTD CO
Ordinary Shares, par value $0.01 per share
S - Sale X -9,215 3,300 -73.63 75.44 -695,206 248,962
2023-05-17 2023-05-17 4 PRTA PROTHENA CORP PUBLIC LTD CO
Ordinary Shares, par value $0.01 per share
S - Sale X -37,044 12,515 -74.75 74.55 -2,761,475 932,941
2023-05-17 2023-05-17 4 PRTA PROTHENA CORP PUBLIC LTD CO
Ordinary Shares, par value $0.01 per share
S - Sale X -34,640 49,559 -41.14 73.54 -2,547,311 3,644,405
2023-05-17 2023-05-17 4 PRTA PROTHENA CORP PUBLIC LTD CO
Ordinary Shares, par value $0.01 per share
S - Sale X -14,001 84,199 -14.26 72.66 -1,017,325 6,117,975
2023-05-17 2023-05-17 4 PRTA PROTHENA CORP PUBLIC LTD CO
Ordinary Shares, par value $0.01 per share
M - Exercise 50,000 98,200 103.73 22.85 1,142,500 2,243,870
2023-05-17 2023-05-17 4 PRTA PROTHENA CORP PUBLIC LTD CO
Ordinary Shares, par value $0.01 per share
M - Exercise 45,000 48,200 1,406.25 29.81 1,341,450 1,436,842
2023-03-17 2023-03-15 4 PRTA PROTHENA CORP PUBLIC LTD CO
Ordinary Shares, par value $0.01 per share
S - Sale X -5,198 3,200 -61.90 48.68 -253,029 155,770
2023-03-17 2023-03-15 4 PRTA PROTHENA CORP PUBLIC LTD CO
Ordinary Shares, par value $0.01 per share
S - Sale X -4,802 8,398 -36.38 48.16 -231,285 404,485
2023-03-17 2023-03-15 4 PRTA PROTHENA CORP PUBLIC LTD CO
Ordinary Shares, par value $0.01 per share
M - Exercise 10,000 13,200 312.50 6.73 67,300 88,836
2023-02-17 2023-02-15 4 PRTA PROTHENA CORP PUBLIC LTD CO
Ordinary Shares, par value $0.01 per share
S - Sale X -664 3,200 -17.18 53.87 -35,771 172,389
2023-02-17 2023-02-15 4 PRTA PROTHENA CORP PUBLIC LTD CO
Ordinary Shares, par value $0.01 per share
S - Sale X -9,336 3,864 -70.73 53.30 -497,627 205,959
2023-02-17 2023-02-15 4 PRTA PROTHENA CORP PUBLIC LTD CO
Ordinary Shares, par value $0.01 per share
M - Exercise 10,000 13,200 312.50 6.73 67,300 88,836
2023-01-20 2023-01-18 4 PRTA PROTHENA CORP PUBLIC LTD CO
Ordinary Shares, par value $0.01 per share
S - Sale X -638 3,200 -16.62 56.97 -36,347 182,307
2023-01-20 2023-01-18 4 PRTA PROTHENA CORP PUBLIC LTD CO
Ordinary Shares, par value $0.01 per share
S - Sale X -2,085 3,838 -35.20 56.32 -117,436 216,172
2023-01-20 2023-01-18 4 PRTA PROTHENA CORP PUBLIC LTD CO
Ordinary Shares, par value $0.01 per share
S - Sale X -7,277 5,923 -55.13 55.18 -401,523 326,813
2023-01-20 2023-01-18 4 PRTA PROTHENA CORP PUBLIC LTD CO
Ordinary Shares, par value $0.01 per share
M - Exercise 10,000 13,200 312.50 6.73 67,300 88,836
2022-12-23 2022-12-21 4 PRTA PROTHENA CORP PUBLIC LTD CO
Ordinary Shares, par value $0.01 per share
S - Sale X -6,845 3,200 -68.14 59.21 -405,264 189,459
2022-12-23 2022-12-21 4 PRTA PROTHENA CORP PUBLIC LTD CO
Ordinary Shares, par value $0.01 per share
S - Sale X -3,155 10,045 -23.90 58.46 -184,426 587,181
2022-12-23 2022-12-21 4 PRTA PROTHENA CORP PUBLIC LTD CO
Ordinary Shares, par value $0.01 per share
M - Exercise 10,000 13,200 312.50 6.73 67,300 88,836
2022-11-25 2022-11-23 4 PRTA PROTHENA CORP PUBLIC LTD CO
Ordinary Shares, par value $0.01 per share
S - Sale X -1,469 3,200 -31.46 62.28 -91,488 199,292
2022-11-25 2022-11-23 4 PRTA PROTHENA CORP PUBLIC LTD CO
Ordinary Shares, par value $0.01 per share
S - Sale X -3,984 4,669 -46.04 61.28 -244,125 286,100
2022-11-25 2022-11-23 4 PRTA PROTHENA CORP PUBLIC LTD CO
Ordinary Shares, par value $0.01 per share
S - Sale X -4,547 8,653 -34.45 60.53 -275,241 523,787
2022-11-25 2022-11-23 4 PRTA PROTHENA CORP PUBLIC LTD CO
Ordinary Shares, par value $0.01 per share
M - Exercise 10,000 13,200 312.50 6.73 67,300 88,836
2022-10-21 2022-10-19 4 PRTA PROTHENA CORP PUBLIC LTD CO
Ordinary Shares, par value $0.01 per share
S - Sale X -171 3,200 -5.07 58.17 -9,948 186,159
2022-10-21 2022-10-19 4 PRTA PROTHENA CORP PUBLIC LTD CO
Ordinary Shares, par value $0.01 per share
S - Sale X -4,541 3,371 -57.39 57.30 -260,212 193,168
2022-10-21 2022-10-19 4 PRTA PROTHENA CORP PUBLIC LTD CO
Ordinary Shares, par value $0.01 per share
S - Sale X -2,520 7,912 -24.16 56.30 -141,885 445,475
2022-10-21 2022-10-19 4 PRTA PROTHENA CORP PUBLIC LTD CO
Ordinary Shares, par value $0.01 per share
S - Sale X -2,768 10,432 -20.97 55.04 -152,340 574,136
2022-10-21 2022-10-19 4 PRTA PROTHENA CORP PUBLIC LTD CO
Ordinary Shares, par value $0.01 per share
M - Exercise 10,000 13,200 312.50 6.73 67,300 88,836
2022-09-23 2022-09-21 4 PRTA PROTHENA CORP PUBLIC LTD CO
Ordinary Shares, par value $0.01 per share
S - Sale X -10,000 3,200 -75.76 30.75 -307,496 98,399
2022-09-23 2022-09-21 4 PRTA PROTHENA CORP PUBLIC LTD CO
Ordinary Shares, par value $0.01 per share
M - Exercise 10,000 13,200 312.50 6.73 67,300 88,836
2022-08-26 2022-08-24 4 PRTA PROTHENA CORP PUBLIC LTD CO
Ordinary Shares, par value $0.01 per share
S - Sale X -10,000 3,200 -75.76 30.17 -301,672 96,535
2022-08-26 2022-08-24 4 PRTA PROTHENA CORP PUBLIC LTD CO
Ordinary Shares, par value $0.01 per share
M - Exercise 10,000 13,200 312.50 6.73 67,300 88,836
2022-07-22 2022-07-22 4 PRTA PROTHENA CORP PUBLIC LTD CO
Ordinary Shares, par value $0.01 per share
S - Sale X -7,320 3,200 -69.58 32.55 -238,254 104,155
2022-07-22 2022-07-22 4 PRTA PROTHENA CORP PUBLIC LTD CO
Ordinary Shares, par value $0.01 per share
M - Exercise 7,320 10,520 228.75 6.73 49,264 70,800
2022-07-22 2022-07-21 4 PRTA PROTHENA CORP PUBLIC LTD CO
Ordinary Shares, par value $0.01 per share
S - Sale X -5 3,200 -0.16 33.69 -168 107,808
2022-07-22 2022-07-21 4 PRTA PROTHENA CORP PUBLIC LTD CO
Ordinary Shares, par value $0.01 per share
S - Sale X -20,555 3,205 -86.51 32.64 -670,925 104,613
2022-07-22 2022-07-21 4 PRTA PROTHENA CORP PUBLIC LTD CO
Ordinary Shares, par value $0.01 per share
M - Exercise 20,560 23,760 642.50 6.73 138,369 159,905
2022-07-22 2022-07-20 4 PRTA PROTHENA CORP PUBLIC LTD CO
Ordinary Shares, par value $0.01 per share
S - Sale X -16,984 3,200 -84.15 32.73 -555,922 104,743
2022-07-22 2022-07-20 4 PRTA PROTHENA CORP PUBLIC LTD CO
Ordinary Shares, par value $0.01 per share
S - Sale X -25,136 20,184 -55.46 32.32 -812,519 652,446
2022-07-22 2022-07-20 4 PRTA PROTHENA CORP PUBLIC LTD CO
Ordinary Shares, par value $0.01 per share
M - Exercise 42,120 45,320 1,316.25 6.73 283,468 305,004
2022-02-25 2022-02-23 4 PRTA PROTHENA CORP PUBLIC LTD CO
Stock Option (Right to Buy)
A - Award 85,000 85,000
2021-02-26 2021-02-25 4 PRTA PROTHENA CORP PUBLIC LTD CO
Stock Option (Right to Buy)
A - Award 84,000 84,000
2021-02-17 2021-02-12 4 PRTA PROTHENA CORP PUBLIC LTD CO
Employee Stock Option (Right to Buy)
A - Award 60,150 60,150
2021-02-17 2021-02-12 4 PRTA PROTHENA CORP PUBLIC LTD CO
Employee Stock Option (Right to Buy)
D - Sale to Issuer -80,000 0 -100.00
2021-02-17 2021-02-12 4 PRTA PROTHENA CORP PUBLIC LTD CO
Employee Stock Option (Right to Buy)
A - Award 39,062 39,062
2021-02-17 2021-02-12 4 PRTA PROTHENA CORP PUBLIC LTD CO
Employee Stock Option (Right to Buy)
D - Sale to Issuer -75,000 0 -100.00
2021-02-17 2021-02-12 4 PRTA PROTHENA CORP PUBLIC LTD CO
Employee Stock Option (Right to Buy)
A - Award 40,625 40,625
2021-02-17 2021-02-12 4 PRTA PROTHENA CORP PUBLIC LTD CO
Employee Stock Option (Right to Buy)
D - Sale to Issuer -65,000 0 -100.00
2021-02-17 2021-02-12 4 PRTA PROTHENA CORP PUBLIC LTD CO
Employee Stock Option (Right to Buy)
A - Award 50,000 50,000
2021-02-17 2021-02-12 4 PRTA PROTHENA CORP PUBLIC LTD CO
Employee Stock Option (Right to Buy)
D - Sale to Issuer -55,000 0 -100.00
2020-02-27 2020-02-25 4 PRTA Prothena Corp plc
Stock Option (Right to Buy)
A - Award 105,000 105,000
2019-06-12 2019-06-11 4 SRRA Sierra Oncology, Inc.
Stock Option (right to buy)
A - Award 30,000 30,000
2019-03-01 2019-02-27 4 PRTA Prothena Corp plc
Stock Option (right to buy)
A - Award 95,000 95,000
2018-06-25 2018-06-21 4 PRTA Prothena Corp plc
Stock Option (right to buy)
A - Award 250,000 250,000
2018-06-14 2018-06-12 4 SRRA Sierra Oncology, Inc.
Stock Option (right to buy)
A - Award 25,000 25,000
2018-02-23 2018-02-21 4 PRTA Prothena Corp plc
Stock Option (right to buy)
A - Award 80,000 80,000
2017-06-14 2017-06-13 4 SRRA Sierra Oncology, Inc.
Stock Option (right to buy)
A - Award 25,000 25,000
2017-03-09 2017-03-09 4 PRTA Prothena Corp plc
Ordinary Shares, par value $0.01 per share
P - Purchase 1,000 3,200 45.45 51.32 51,317 164,215
2017-02-24 2017-02-22 4 PRTA Prothena Corp plc
Stock Option (right to buy)
A - Award 75,000 75,000
2016-06-13 2016-06-09 4 DNAI ProNAi Therapeutics Inc
Stock Option (right to buy)
A - Award 77,670 77,670
2016-03-24 3 DNAI ProNAi Therapeutics Inc
No securities beneficially held
0
2016-02-26 2016-02-24 4 PRTA Prothena Corp plc
Stock Option (right to buy)
A - Award 65,000 65,000
2015-12-11 2015-12-09 4 PRTA Prothena Corp plc
Stock Option (right to buy)
M - Exercise -30,000 150,000 -16.67
2015-12-11 2015-12-09 4 PRTA Prothena Corp plc
Ordinary Shares, par value $0.01 per share
S - Sale X -2,100 2,200 -48.84 67.00 -140,704 147,405
2015-12-11 2015-12-09 4 PRTA Prothena Corp plc
Ordinary Shares, par value $0.01 per share
S - Sale X -19,731 4,300 -82.11 66.37 -1,309,515 285,384
2015-12-11 2015-12-09 4 PRTA Prothena Corp plc
Ordinary Shares, par value $0.01 per share
S - Sale X -8,169 24,031 -25.37 65.46 -534,756 1,573,108
2015-12-11 2015-12-09 4 PRTA Prothena Corp plc
Ordinary Shares, par value $0.01 per share
M - Exercise 30,000 32,200 1,363.64 6.73 201,900 216,706
2015-03-12 2015-03-11 4 PRTA Prothena Corp plc
Stock Option (right to buy)
A - Award 55,000 55,000
2014-05-12 2014-05-09 4 PRTA Prothena Corp plc
Ordinary Shares, par value $0.01 per share
P - Purchase 2,200 2,200 19.61 43,134 43,134
2014-02-06 2014-02-04 4 PRTA Prothena Corp plc
Stock Option (right to buy)
A - Award 45,000 45,000
2013-04-02 2013-04-01 4 PRTA Prothena Corp plc
Stock Option (right to buy)
A - Award 180,000 180,000
2013-03-08 2013-03-06 4 SOMX Pernix Sleep, Inc.
Common Stock
D - Sale to Issuer -42,419 0 -100.00
2013-01-03 2013-01-02 4 SOMX Somaxon Pharmaceuticals, Inc.
Common Stock
S - Sale X -412 49,949 -0.82 3.08 -1,269 153,843
2013-01-03 2012-12-31 4 SOMX Somaxon Pharmaceuticals, Inc.
Common Stock
A - Award 1,494 50,361 3.06
2012-11-20 2012-11-16 4 SOMX Somaxon Pharmaceuticals, Inc.
Common Stock
A - Award 30,000 52,617 132.64
2012-10-02 2012-09-30 4 SOMX Somaxon Pharmaceuticals, Inc.
Common Stock
A - Award 15,716 150,941 11.62
2012-07-03 2012-07-02 4 SOMX Somaxon Pharmaceuticals, Inc.
Common Stock
A - Award 15,992 135,225 13.41
2012-01-04 2012-01-03 4 SOMX Somaxon Pharmaceuticals, Inc.
Common Stock
S - Sale X -3,300 119,233 -2.69 0.48 -1,575 56,898
P
Open market or private purchase of non-derivative or derivative security
S
Open market or private sale of non-derivative or derivative security
A
Grant, award, or other acquisition of securities from the company (such as an option)
C
Conversion of derivative
D
Sale or transfer of securities back to the company
F
Payment of exercise price or tax liability using portion of securities received from the company
G
Gift of securities by or to the insider
K
Equity swaps and similar hedging transactions
M
Exercise or conversion of derivative security received from the company (such as an option)
V
A transaction voluntarily reported on Form 4
J
Other (accompanied by a footnote describing the transaction)