Prothena Corporation PLC (PRTA)

In the last 90 days, Prothena Corporation PLC saw insider activity with a net buy value of $1.92 million. This includes significant buying by William P. Scully totaling approximately $2.45 million across multiple transactions. A proposed sale of $740,000 by Michael J. Malecek was also noted.
Stock chart
Ticker: PRTA Exchange: NSM


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Purchase Sale Planned purchase Planned sale Net purchase Net sale Activity signal Earnings
Top insiders
Trades
MALECEK MICHAEL J
Previous Officer
1 sale — total 100,000 USD
Proposed sale 9 Jun 2026
Value US$101,787.17 | Price 223.12 | Shares 94,333
Buy 4 Jun 2026
Value US$951,022.87 | Price 401.54 | Shares 1,780
Buy 2 Jun 2026
Value US$100,000.00 | Price 9.43 | Shares 1,000
Buy 22 May 2026
Value US$100,000.00 | Price 9.81 | Shares 1,000
Sale 6 May 2025
Value US$15,164,712.29 | Price 7.64 | Shares 1,984,053
Sale 5 May 2025
Value US$7,930,165.69 | Price 8.11 | Shares 977,693
Sale 2 May 2025
Value US$27,744,929.35 | Price 8.36 | Shares 3,317,938
Buy 14 Jan 2025
Value US$1,279,040.00 | Price 12.79 | Shares 100,000
Buy 31 Dec 2024
Value US$389,640.00 | Price 12.99 | Shares 30,000
Buy 31 Dec 2024
Value US$10,715.20 | Price 13.39 | Shares 800
Buy 31 Dec 2024
Value US$16,038.24 | Price 13.37 | Shares 1,200
Buy 20 Dec 2024
Value US$31,813.00 | Price 15.91 | Shares 2,000
Buy 18 Dec 2024
Value US$1,022,669.74 | Price 13.93 | Shares 73,436
Proposed sale 24 Jan 2024
Value US$170,000.00 | Price 34.00 | Shares 5,000
Planned sale 24 Jan 2024
Value US$170,000.00 | Price 34.00 | Shares 5,000
Proposed sale 20 Dec 2023
Value US$186,450.00 | Price 37.29 | Shares 5,000
Planned sale 20 Dec 2023
Value US$124,408.57 | Price 37.45 | Shares 3,322
Planned sale 20 Dec 2023
Value US$61,543.17 | Price 36.68 | Shares 1,678
Proposed sale 30 Nov 2023
Value US$170,000.00 | Price 34.00 | Shares 5,000
Planned sale 30 Nov 2023
Value US$170,000.00 | Price 34.00 | Shares 5,000
Proposed sale 25 Oct 2023
Value US$206,350.00 | Price 41.27 | Shares 5,000
Planned sale 25 Oct 2023
Value US$12,430.11 | Price 42.28 | Shares 294
Planned sale 25 Oct 2023
Value US$120,718.00 | Price 41.38 | Shares 2,917
Planned sale 25 Oct 2023
Value US$72,043.21 | Price 40.27 | Shares 1,789
Proposed sale 11 Oct 2023
Value US$189,160.00 | Price 47.29 | Shares 4,000
Planned sale 11 Oct 2023
Value US$21,198.20 | Price 47.74 | Shares 444
Planned sale 11 Oct 2023
Value US$165,786.41 | Price 46.62 | Shares 3,556
Proposed sale 4 Oct 2023
Value US$237,000.00 | Price 47.40 | Shares 5,000
Planned sale 4 Oct 2023
Value US$31,355.26 | Price 47.29 | Shares 663
Planned sale 4 Oct 2023
Value US$201,729.05 | Price 46.51 | Shares 4,337
Proposed sale 27 Sep 2023
Value US$241,050.00 | Price 48.21 | Shares 5,000
Planned sale 27 Sep 2023
Value US$19,519.18 | Price 48.31 | Shares 404
Planned sale 27 Sep 2023
Value US$217,365.52 | Price 47.29 | Shares 4,596
Proposed sale 25 Sep 2023
Value US$1,750,000.00 | Price 50.00 | Shares 35,000
Proposed sale 19 Sep 2023
Value US$261,806.50 | Price 52.36 | Shares 5,000
Planned sale 19 Sep 2023
Value US$261,807.00 | Price 52.36 | Shares 5,000
Proposed sale 13 Sep 2023
Value US$110,780.00 | Price 55.39 | Shares 2,000
Planned sale 13 Sep 2023
Value US$110,952.20 | Price 55.48 | Shares 2,000
Proposed sale 13 Sep 2023
Value US$221,560.00 | Price 55.39 | Shares 4,000
Planned sale 13 Sep 2023
Value US$6,379.02 | Price 55.96 | Shares 114
Planned sale 13 Sep 2023
Value US$215,584.01 | Price 55.48 | Shares 3,886
Proposed sale 6 Sep 2023
Value US$273,050.00 | Price 54.61 | Shares 5,000
Planned sale 6 Sep 2023
Value US$331.62 | Price 55.27 | Shares 6
Planned sale 6 Sep 2023
Value US$273,471.94 | Price 54.76 | Shares 4,994
Proposed sale 30 Aug 2023
Value US$275,066.00 | Price 55.01 | Shares 5,000
Planned sale 30 Aug 2023
Value US$786.94 | Price 56.21 | Shares 14
Planned sale 30 Aug 2023
Value US$147,551.23 | Price 55.39 | Shares 2,664
Planned sale 30 Aug 2023
Value US$126,727.79 | Price 54.58 | Shares 2,322
Proposed sale 18 Aug 2023
Value US$285,922.00 | Price 57.18 | Shares 5,000
Planned sale 18 Aug 2023
Value US$285,922.50 | Price 57.18 | Shares 5,000
Proposed sale 16 Aug 2023
Value US$234,844.00 | Price 58.71 | Shares 4,000
Planned sale 16 Aug 2023
Value US$24,025.27 | Price 59.91 | Shares 401
Planned sale 16 Aug 2023
Value US$81,216.66 | Price 59.15 | Shares 1,373
Planned sale 16 Aug 2023
Value US$129,602.17 | Price 58.22 | Shares 2,226
Proposed sale 16 Aug 2023
Value US$117,480.00 | Price 58.74 | Shares 2,000
Planned sale 16 Aug 2023
Value US$22,341.45 | Price 59.74 | Shares 374
Planned sale 16 Aug 2023
Value US$44,079.19 | Price 58.93 | Shares 748
Planned sale 16 Aug 2023
Value US$51,059.39 | Price 58.15 | Shares 878
Proposed sale 2 Aug 2023
Value US$268,181.60 | Price 67.05 | Shares 4,000
Planned sale 2 Aug 2023
Value US$15,588.63 | Price 68.07 | Shares 229
Planned sale 2 Aug 2023
Value US$252,592.89 | Price 66.98 | Shares 3,771
Proposed sale 2 Aug 2023
Value US$335,072.00 | Price 67.01 | Shares 5,000
Planned sale 2 Aug 2023
Value US$22,288.09 | Price 67.95 | Shares 328
Planned sale 2 Aug 2023
Value US$312,783.86 | Price 66.95 | Shares 4,672
Proposed sale 26 Jul 2023
Value US$311,638.00 | Price 62.33 | Shares 5,000
Planned sale 26 Jul 2023
Value US$39,309.05 | Price 63.40 | Shares 620
Planned sale 26 Jul 2023
Value US$119,297.36 | Price 62.69 | Shares 1,903
Planned sale 26 Jul 2023
Value US$153,031.78 | Price 61.78 | Shares 2,477
Proposed sale 19 Jul 2023
Value US$345,943.00 | Price 69.19 | Shares 5,000
Planned sale 19 Jul 2023
Value US$72,459.00 | Price 70.08 | Shares 1,034
Planned sale 19 Jul 2023
Value US$273,484.26 | Price 68.96 | Shares 3,966
Proposed sale 12 Jul 2023
Value US$135,026.60 | Price 67.51 | Shares 2,000
Proposed sale 12 Jul 2023
Value US$270,025.60 | Price 67.51 | Shares 4,000
Planned sale 12 Jul 2023
Value US$54,358.40 | Price 67.95 | Shares 800
Planned sale 12 Jul 2023
Value US$215,667.20 | Price 67.40 | Shares 3,200
Abbreviations B: Buy, S: Sell, PP: Planned purchase, PlS: Planned sale, PrS: Proposed sale, O: Option / Other
Notification date Transaction date B/S Transaction type Insider and/or position Nb. shares
Price
Value
Number of shares Price Value Details
2026-06-09 2026-06-09 PrS Proposed sale

Previous Officer

Officer
94,333
223.12
US$101,787
94,333 223.12 US$101,787
2026-06-05 2026-06-04 B Purchase Large shareholder
1,780 +49.9%
401.54
US$951,023
1,780 +49.9% 401.54 US$951,023
2026-06-03 2026-06-02 B Purchase Large shareholder
42,184 -34.6%
375.66
US$1,382,951
42,184 -34.6% 375.66 US$1,382,951
2026-05-26 2026-05-22 B Purchase Large shareholder
1,000 +13.6%
9.81
US$100,000
1,000 +13.6% 9.81 US$100,000
2025-05-06 2025-05-06 S Sale Large shareholder
1,984,053 -27.2%
7.64
US$15,164,712
1,984,053 -27.2% 7.64 US$15,164,712
2025-05-06 2025-05-05 S Sale Large shareholder
977,693 -11.8%
8.11
US$7,930,166
977,693 -11.8% 8.11 US$7,930,166
2025-05-06 2025-05-02 S Sale Large shareholder
3,317,938 -28.6%
8.36
US$27,744,929
3,317,938 -28.6% 8.36 US$27,744,929
2025-05-02 2025-01-14 B Purchase Large shareholder
100,000 +15.7%
12.79
US$1,279,040
100,000 +15.7% 12.79 US$1,279,040
2025-05-02 2024-12-31 B Purchase Large shareholder
30,000 +4.8%
12.99
US$389,640
30,000 +4.8% 12.99 US$389,640
2025-05-02 2024-12-31 B Purchase Large shareholder
800 +0.1%
13.39
US$10,715
800 +0.1% 13.39 US$10,715
2025-05-02 2024-12-31 B Purchase Large shareholder
1,200 +0.2%
13.37
US$16,038
1,200 +0.2% 13.37 US$16,038
2025-05-02 2024-12-20 B Purchase Large shareholder
2,000 +0.3%
15.91
US$31,813
2,000 +0.3% 15.91 US$31,813
2025-05-02 2024-12-18 B Purchase Large shareholder
73,436 +6.0%
13.93
US$1,022,670
73,436 +6.0% 13.93 US$1,022,670
2024-01-24 2024-01-24 PrS Proposed sale

Officer

Officer
5,000
34.00
US$170,000
5,000 34.00 US$170,000
2024-01-24 2024-01-24 PlS Planned sale

Chief Accounting Officer

Officer
5,000 -100.0%
34.00
US$170,000
5,000 -100.0% 34.00 US$170,000
2023-12-20 2023-12-20 PrS Proposed sale

Officer

Officer
5,000
37.29
US$186,450
5,000 37.29 US$186,450
2023-12-20 2023-12-20 PlS Planned sale

Chief Accounting Officer

Officer
3,322 -100.0%
37.45
US$124,409
3,322 -100.0% 37.45 US$124,409
2023-12-20 2023-12-20 PlS Planned sale

Chief Accounting Officer

Officer
1,678 -33.6%
36.68
US$61,543
1,678 -33.6% 36.68 US$61,543
2023-11-30 2023-11-30 PrS Proposed sale

Officer

Officer
5,000
34.00
US$170,000
5,000 34.00 US$170,000
2023-11-30 2023-11-30 PlS Planned sale

Chief Accounting Officer

Officer
5,000 -100.0%
34.00
US$170,000
5,000 -100.0% 34.00 US$170,000
2023-10-25 2023-10-25 PrS Proposed sale

Officer

Officer
5,000
41.27
US$206,350
5,000 41.27 US$206,350
2023-10-25 2023-10-25 PlS Planned sale

Chief Accounting Officer

Officer
294 -100.0%
42.28
US$12,430
294 -100.0% 42.28 US$12,430
2023-10-25 2023-10-25 PlS Planned sale

Chief Accounting Officer

Officer
2,917 -90.8%
41.38
US$120,718
2,917 -90.8% 41.38 US$120,718
2023-10-25 2023-10-25 PlS Planned sale

Chief Accounting Officer

Officer
1,789 -35.8%
40.27
US$72,043
1,789 -35.8% 40.27 US$72,043
2023-10-11 2023-10-11 PrS Proposed sale

Officer

Officer
4,000
47.29
US$189,160
4,000 47.29 US$189,160
2023-10-11 2023-10-11 PlS Planned sale

Chief Operating Officer

Officer
444 -100.0%
47.74
US$21,198
444 -100.0% 47.74 US$21,198
2023-10-11 2023-10-11 PlS Planned sale

Chief Operating Officer

Officer
3,556 -88.9%
46.62
US$165,786
3,556 -88.9% 46.62 US$165,786
2023-10-04 2023-10-04 PrS Proposed sale

Officer

Officer
5,000
47.40
US$237,000
5,000 47.40 US$237,000
2023-10-04 2023-10-04 PlS Planned sale

Chief Regulatory Officer

Officer
663 -100.0%
47.29
US$31,355
663 -100.0% 47.29 US$31,355
2023-10-04 2023-10-04 PlS Planned sale

Chief Regulatory Officer

Officer
4,337 -86.7%
46.51
US$201,729
4,337 -86.7% 46.51 US$201,729
2023-09-27 2023-09-27 PrS Proposed sale

Officer

Officer
5,000
48.21
US$241,050
5,000 48.21 US$241,050
2023-09-27 2023-09-27 PlS Planned sale

Chief Legal Officer

Officer
404 -100.0%
48.31
US$19,519
404 -100.0% 48.31 US$19,519
2023-09-27 2023-09-27 PlS Planned sale

Chief Legal Officer

Officer
4,596 -91.9%
47.29
US$217,366
4,596 -91.9% 47.29 US$217,366
2023-09-25 2023-09-25 PrS Proposed sale

Director

Non-Executive Director
35,000
50.00
US$1,750,000
35,000 50.00 US$1,750,000
2023-09-19 2023-09-19 PrS Proposed sale

Officer

Officer
5,000
52.36
US$261,806
5,000 52.36 US$261,806
2023-09-19 2023-09-19 PlS Planned sale

Chief Accounting Officer

Officer
5,000 -100.0%
52.36
US$261,807
5,000 -100.0% 52.36 US$261,807
2023-09-13 2023-09-13 PrS Proposed sale

Officer

Officer
2,000
55.39
US$110,780
2,000 55.39 US$110,780
2023-09-13 2023-09-13 PrS Proposed sale

Officer

Officer
4,000
55.39
US$221,560
4,000 55.39 US$221,560
2023-09-13 2023-09-13 PlS Planned sale

Chief Operating Officer

Officer
114 -100.0%
55.96
US$6,379
114 -100.0% 55.96 US$6,379
2023-09-13 2023-09-13 PlS Planned sale

Chief Operating Officer

Officer
3,886 -97.2%
55.48
US$215,584
3,886 -97.2% 55.48 US$215,584
2023-09-13 2023-09-13 PlS Planned sale

Chief Medical Officer

Officer
2,000 -100.0%
55.48
US$110,952
2,000 -100.0% 55.48 US$110,952
2023-09-06 2023-09-06 PrS Proposed sale

Officer

Officer
5,000
54.61
US$273,050
5,000 54.61 US$273,050
2023-09-06 2023-09-06 PlS Planned sale

Chief Regulatory Officer

Officer
6 -100.0%
55.27
US$332
6 -100.0% 55.27 US$332
2023-09-06 2023-09-06 PlS Planned sale

Chief Regulatory Officer

Officer
4,994 -99.9%
54.76
US$273,472
4,994 -99.9% 54.76 US$273,472
2023-08-30 2023-08-30 PrS Proposed sale

Officer

Officer
5,000
55.01
US$275,066
5,000 55.01 US$275,066
2023-08-30 2023-08-30 PlS Planned sale

Chief Legal Officer

Officer
14 -100.0%
56.21
US$787
14 -100.0% 56.21 US$787
2023-08-30 2023-08-30 PlS Planned sale

Chief Legal Officer

Officer
2,664 -99.5%
55.39
US$147,551
2,664 -99.5% 55.39 US$147,551
2023-08-30 2023-08-30 PlS Planned sale

Chief Legal Officer

Officer
2,322 -46.4%
54.58
US$126,728
2,322 -46.4% 54.58 US$126,728
2023-08-18 2023-08-18 PrS Proposed sale

Officer

Officer
5,000
57.18
US$285,922
5,000 57.18 US$285,922
2023-08-18 2023-08-18 PlS Planned sale

Chief Accounting Officer

Officer
5,000 -100.0%
57.18
US$285,922
5,000 -100.0% 57.18 US$285,922
2023-08-16 2023-08-16 PrS Proposed sale

Officer

Officer
4,000
58.71
US$234,844
4,000 58.71 US$234,844
2023-08-16 2023-08-16 PrS Proposed sale

Officer

Officer
2,000
58.74
US$117,480
2,000 58.74 US$117,480
2023-08-16 2023-08-16 PlS Planned sale

Chief Operating Officer

Officer
401 -100.0%
59.91
US$24,025
401 -100.0% 59.91 US$24,025
2023-08-16 2023-08-16 PlS Planned sale

Chief Operating Officer

Officer
1,373 -77.4%
59.15
US$81,217
1,373 -77.4% 59.15 US$81,217
2023-08-16 2023-08-16 PlS Planned sale

Chief Operating Officer

Officer
2,226 -55.6%
58.22
US$129,602
2,226 -55.6% 58.22 US$129,602
2023-08-16 2023-08-16 PlS Planned sale

Chief Medical Officer

Officer
374 -100.0%
59.74
US$22,341
374 -100.0% 59.74 US$22,341
2023-08-16 2023-08-16 PlS Planned sale

Chief Medical Officer

Officer
748 -66.7%
58.93
US$44,079
748 -66.7% 58.93 US$44,079
2023-08-16 2023-08-16 PlS Planned sale

Chief Medical Officer

Officer
878 -43.9%
58.15
US$51,059
878 -43.9% 58.15 US$51,059
2023-08-02 2023-08-02 PrS Proposed sale

Officer

Officer
4,000
67.05
US$268,182
4,000 67.05 US$268,182
2023-08-02 2023-08-02 PrS Proposed sale

Officer

Officer
5,000
67.01
US$335,072
5,000 67.01 US$335,072
2023-08-02 2023-08-02 PlS Planned sale

Chief Regulatory Officer

Officer
328 -100.0%
67.95
US$22,288
328 -100.0% 67.95 US$22,288
2023-08-02 2023-08-02 PlS Planned sale

Chief Regulatory Officer

Officer
4,672 -93.4%
66.95
US$312,784
4,672 -93.4% 66.95 US$312,784
2023-08-02 2023-08-02 PlS Planned sale

Chief Scientific Officer

Officer
229 -100.0%
68.07
US$15,589
229 -100.0% 68.07 US$15,589
2023-08-02 2023-08-02 PlS Planned sale

Chief Scientific Officer

Officer
3,771 -94.3%
66.98
US$252,593
3,771 -94.3% 66.98 US$252,593
2023-07-26 2023-07-26 PrS Proposed sale

Officer

Officer
5,000
62.33
US$311,638
5,000 62.33 US$311,638
2023-07-26 2023-07-26 PlS Planned sale

Chief Legal Officer

Officer
620 -100.0%
63.40
US$39,309
620 -100.0% 63.40 US$39,309
2023-07-26 2023-07-26 PlS Planned sale

Chief Legal Officer

Officer
1,903 -75.4%
62.69
US$119,297
1,903 -75.4% 62.69 US$119,297
2023-07-26 2023-07-26 PlS Planned sale

Chief Legal Officer

Officer
2,477 -49.5%
61.78
US$153,032
2,477 -49.5% 61.78 US$153,032
2023-07-19 2023-07-19 PrS Proposed sale

Officer

Officer
5,000
69.19
US$345,943
5,000 69.19 US$345,943
2023-07-19 2023-07-19 PlS Planned sale

Chief Accounting Officer

Officer
1,034 -100.0%
70.08
US$72,459
1,034 -100.0% 70.08 US$72,459
2023-07-19 2023-07-19 PlS Planned sale

Chief Accounting Officer

Officer
3,966 -79.3%
68.96
US$273,484
3,966 -79.3% 68.96 US$273,484
2023-07-12 2023-07-12 PrS Proposed sale

Officer

Officer
2,000
67.51
US$135,027
2,000 67.51 US$135,027
2023-07-12 2023-07-12 PrS Proposed sale

Officer

Officer
4,000
67.51
US$270,026
4,000 67.51 US$270,026
2023-07-12 2023-07-12 PlS Planned sale

Chief Operating Officer

Officer
800 -100.0%
67.95
US$54,358
800 -100.0% 67.95 US$54,358
2023-07-12 2023-07-12 PlS Planned sale

Chief Operating Officer

Officer
3,200 -80.0%
67.40
US$215,667
3,200 -80.0% 67.40 US$215,667