Prothena Corporation plc
US ˙ NasdaqGS ˙ IE00B91XRN20

SecurityPRTA / Prothena Corporation plc
InstitutionWalleye Capital LLC
Latest Disclosed Ownership277,168 shares
Latest Disclosed Value $ 2,694,073
Walleye Capital LLC ownership in PRTA / Prothena Corporation plc

On May 13, 2026 - Walleye Capital LLC filed a 13F-HR/A form disclosing ownership of 277,168 shares of Prothena Corporation plc (US:PRTA) valued at $2,694,073 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 13, 2026 disclosing 156,035 shares of Prothena Corporation plc. This represents a change in shares of 77.63% during the quarter. The current value of the position is $2,472,339 USD.

Walleye Capital LLC has a history of taking positions in derivatives of the underlying security (PRTA) in the form of stock options. The firm currently holds call options representing 200 of underlying shares valued at $1,944 USD and put options representing 0 of underlying shares valued at $0 USD .

Note: prior versions of this page mistakenly stated that the share values represented the number of options, not the number of underlying shares. For more information on the data backing these reports, please see the SEC document Frequently Asked Questions About Form 13F.

Institutional Ownership: 13F and NPORT Filings

The Security and Class in the table below are shown exactly as filed by the investor. We do our best to track continuity of investments through acquisitions, and this will be reflected in the table as changes in names. In addition to descriptive data, performance of the investment is shown over time. To calculate quarterly performance, we first calculate cost basis of the shares purchased during the quarter, then use that to calculate gross profit. Quarterly return is Gross Profit / Starting Portfolio value.

Note that cost basis is calculated and stored in thousands, so small quarterly changes in shares frequently result in a cost basis of zero.

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Institutional Put/Call Ratios
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In addition to reporting standard equity and debt issues, institutions with more than 100MM assets under management must also disclose their put and call option holdings. Since put options generally indicate negative sentiment, and call options indicate positive sentiment, we can get a sense of the overall institutional sentiment by plotting the ratio of puts to calls. The chart to the right plots the historical put/call ratio for this instrument.

Using Put/Call Ratio as an indicator of investor sentiment overcomes one of the key deficiencies of using total institutional ownership, which is that a significant amount of assets under management are invested passively to track indices. Passively-managed funds do not typically buy options, so the put/call ratio indicator more closely tracks the sentiment of actively-managed funds.

PRTA / Prothena Corporation plc Historical Put/Call Ratio
Disclosed Equity Positions (from 13F/NPORT Filings)
File
Date
Effective
Date
Form Security Class ID Avg Price
Paid (Est)
Reported
Shares
ΔShares ΔShares
(%)
Reported
Value
(x1000)
ΔValue
(%)
Alloc
(%)
ΔAlloc ΔAlloc (%) Cost Basis
(x1000)
Unrealized
Gain/Loss
(x1000)
2026-05-13 2026-03-31 13F/A-1 PROTHENA CORP SHS G72800108 277,168 121,133 77.63 2,694 80.81 0.0112
2026-05-08 2026-03-31 13F PROTHENA CORP SHS G72800108 277,168 121,133 2,694 0.0112
2026-02-13 2025-12-31 13F PROTHENA CORP SHS G72800108 156,035 155,972 247,574.60 1,490 0.0046
2025-11-14 2025-09-30 13F PROTHENA CORP SHS G72800108 63 -1,995 -96.94 1 -100.00 0.0000
2025-08-13 2025-06-30 13F PROTHENA CORP SHS G72800108 2,058 2,058 12 0.0000
2025-05-14 2025-03-31 13F PROTHENA CORP SHS G72800108 0 -14,953 -100.00 0 -100.00
2025-02-13 2024-12-31 13F PROTHENA CORP SHS G72800108 14,953 14,953 207 0.0005
2024-11-14 2024-09-30 13F PROTHENA CORP SHS G72800108 0 -46,098 -100.00 0 -100.00
2024-08-14 2024-06-30 13F PROTHENA CORP SHS G72800108 46,098 44,879 3,681.62 951 3,070.00 0.0017
2024-05-15 2024-03-31 13F PROTHENA CORP SHS G72800108 1,219 1,219 30 0.0001
2024-02-14 2023-12-31 13F PROTHENA CORP SHS G72800108 0 -4,286 -100.00 0 -100.00
2023-11-21 2023-09-30 13F/A-1 PROTHENA CORP SHS G72800108 4,286 -51,366 -92.30 207 -94.58 0.0005
2023-11-14 2023-09-30 13F PROTHENA CORP SHS G72800108 4,286 -51,366 207 0.0005
2023-08-14 2023-06-30 13F PROTHENA CORP SHS G72800108 55,652 55,652 3,800 0.0138
2019-08-14 2019-06-30 13F PROTHENA CORP SHS G72800108 0 -7,319 -100.00 0 -100.00
2019-08-14 2019-03-31 13F/A-1 PROTHENA CORP SHS G72800108 7,319 7,319 89 0.0147
2019-05-15 2019-03-31 13F PROTHENA CORP SHS G72800108 7,319 89
Disclosed Call Options
File
Date
Effective
Date
Form Security Class ID Opt Avg Share
Price
Shares ΔShares
(%)
Value
(x1000)
ΔValue
(%)
Prior Allocation
(%)
Allocation
(%)
ΔAllocation
(%)
Cost Basis
(x1000)
Profit
(x1000)
Return
(%)
2026-05-13 2026-03-31 13F/A PROTHENA CORP SHS Call 200 -99.43 2 -99.70 n/a n/a n/a
2026-05-08 2026-03-31 13F PROTHENA CORP SHS Call 200 2 n/a n/a n/a
2026-02-13 2025-12-31 13F PROTHENA CORP SHS Call 35,300 -25.37 337 -26.90 n/a n/a n/a
2025-11-14 2025-09-30 13F PROTHENA CORP SHS Call 47,300 48.28 462 138.86 n/a n/a n/a
2025-08-13 2025-06-30 13F PROTHENA CORP SHS Call 31,900 194 n/a n/a n/a
2024-11-14 2024-09-30 13F PROTHENA CORP SHS Call 0 -100.00 0 -100.00 n/a n/a n/a
2024-08-14 2024-06-30 13F PROTHENA CORP SHS Call 800 -88.06 17 -90.30 n/a n/a n/a
2024-05-15 2024-03-31 13F PROTHENA CORP SHS Call 6,700 166 n/a n/a n/a
2023-11-21 2023-09-30 13F/A PROTHENA CORP SHS Call 0 -100.00 0 -100.00 n/a n/a n/a
2023-11-14 2023-09-30 13F PROTHENA CORP SHS Call 0 0 n/a n/a n/a
2023-08-14 2023-06-30 13F PROTHENA CORP SHS Call 2,900 198 n/a n/a n/a
2019-08-14 2019-06-30 13F PROTHENA CORP SHS Call 0 -100.00 0 -100.00 n/a n/a n/a
2019-08-14 2019-03-31 13F/A PROTHENA CORP SHS Call 5,300 64 n/a n/a n/a
2019-05-15 2019-03-31 13F PROTHENA CORP SHS Call 5,300 64 n/a n/a n/a
Disclosed Put Options
File
Date
Effective
Date
Form Security Class ID Opt Avg Share Price Shares ΔShares
(%)
Value
(x1000)
ΔValue
(%)
Prior Allocation
(%)
Allocation
(%)
ΔAllocation
(%)
Cost Basis
(x1000)
Profit
(x1000)
Return
(%)
2026-05-13 2026-03-31 13F/A PROTHENA CORP SHS Put 0 -100.00 0 -100.00 n/a n/a n/a
2026-05-08 2026-03-31 13F PROTHENA CORP SHS Put 0 0 n/a n/a n/a
2026-02-13 2025-12-31 13F PROTHENA CORP SHS Put 800 -70.37 8 -73.08 n/a n/a n/a
2025-11-14 2025-09-30 13F PROTHENA CORP SHS Put 2,700 26 n/a n/a n/a
2025-05-14 2025-03-31 13F PROTHENA CORP SHS Put 0 -100.00 0 -100.00 n/a n/a n/a
2025-02-13 2024-12-31 13F PROTHENA CORP SHS Put 100 1 n/a n/a n/a
2024-11-14 2024-09-30 13F PROTHENA CORP SHS Put 0 -100.00 0 -100.00 n/a n/a n/a
2024-08-14 2024-06-30 13F PROTHENA CORP SHS Put 8,300 88.64 171 58.33 n/a n/a n/a
2024-05-15 2024-03-31 13F PROTHENA CORP SHS Put 4,400 109 n/a n/a n/a
2024-02-14 2023-12-31 13F PROTHENA CORP SHS Put 0 -100.00 0 -100.00 n/a n/a n/a
2023-11-21 2023-09-30 13F/A PROTHENA CORP SHS Put 700 133.33 34 65.00 n/a n/a n/a
2023-11-14 2023-09-30 13F PROTHENA CORP SHS Put 700 34 n/a n/a n/a
2023-08-14 2023-06-30 13F PROTHENA CORP SHS Put 300 20 n/a n/a n/a
Legend
Shares
The total number of shares held by the institution at the end of the reporting period (the effective date). This is provided in the filing.
Value
The total value of the shares as of the effective date. This is provided in the filing.
Avg. Share Price
The weighted average share price of the shares held by the institution. We use FIFO accounting to determine this price
Class
This is the security class as indicated by the filer. There are a variety of values for this field. Common values include "EC" = equity common, "EP" - equity preferred
Allocation (%)
The percent of the institution's portfolio that this position represents. This is provided in NPORT filings. For 13F filings, we calculate it.
Change in Allocation
The change in allocation from the prior reporting period. This is calculated as current allocation - prior allocation.
Change in Allocation (%)
The percent change in allocation from the prior reporting period. This is calculated as (current allocation - prior allocation) / prior allocation.
Cost Basis
The total cost of the shares held. This is calculated as reported shares * avg. share price
Unrealized Gain/Loss
This is the market value of the position as of the effective date minus the cost basis.