PRTA Prothena Corporation plc

NASDAQ
$8.24

Prothena Corporation plc (PRTA) Insider Activity

What the officers, directors and large holders did with their own shares. Only open-market purchases and sales count toward the totals — grants, option exercises and shares withheld for tax are compensation mechanics, not decisions, and they're listed separately below.

30D 90D 6M 1Y
Insider signal Bullish Insiders bought more than they sold over this window — uncommon at any size.
Cluster activity 1 buyer in the last 30 days 1 buyer in the last 90 days 2 sellers in the last 90 days
Insiders buying
1
9 transactions
Insiders selling
2
2 transactions
Purchases
$4.1M
459,500 shares
Sales
$136.0K
16,048 shares
Net activity
$4.0M
purchases less sales

How much of that selling was preplanned? 100% planned / 0% discretionary

10b5-1 plan sales $136.0K 2 transactions · 16,048 shares
Discretionary sales $0 0 transactions · 0 shares

Largest single sale: $71.1K.

Where they traded

Buy Sell Dot area is proportional to transaction value.

Last open-market purchase: September 2, 2026 , by SCULLY WILLIAM P .

Recent open-market activity

Date Insider Role Action Shares Price Value Held after
SCULLY WILLIAM P 10% Owner Buy 27,000 $9.47 $255.7K 827,000
SCULLY WILLIAM P 10% Owner Buy 50,000 $8.79 $439.4K 800,000
SCULLY WILLIAM P 2 fills 10% Owner Buy 37,500 $8.62 $323.2K 790,000
Isaacs Michael John General Counsel & Company Sec. Sell 10b5-1 8,386 $8.47 $71.1K 35,745 −19% of holding
Kingston Anne Evans Chief Strategy Officer Sell 10b5-1 7,662 $8.47 $64.9K 55,782 −12.1% of holding
SCULLY WILLIAM P 10% Owner Buy 20,000 $7.90 $158.0K 756,000
SCULLY WILLIAM P 10% Owner Buy 125,000 $8.17 $1.0M 1,061,000
SCULLY WILLIAM P 10% Owner Buy 50,000 $9.31 $465.3K 936,000
SCULLY WILLIAM P 10% Owner Buy 50,000 $9.43 $471.3K 886,000
SCULLY WILLIAM P 10% Owner Buy 100,000 $9.81 $981.3K 836,000

Form 4s are due within two business days of a transaction, so this is close to real time — unlike the quarterly 13F data on the Institutional tab. A single large sale often reflects a prearranged 10b5-1 plan rather than a fresh view, so read a pattern of sales rather than any one of them.