STOCK TITAN

Prothena Corp Public Ltd Co (PRTA) holder buys 50,000 shares

Filing Impact
(Moderate)
Filing Sentiment
(Positive)
Form Type
4

Rhea-AI Filing Summary

PROTHENA CORP PUBLIC LTD CO major shareholder William P. Scully reported an open-market purchase of 50,000 ordinary shares on June 4, 2026 at a weighted average price of $9.3059 per share. Following this transaction, he holds 936,000 shares directly.

He also reports indirect holdings of 52,000 shares by his spouse and 80,000 shares by Manatee Equity Fund LLC, and disclaims beneficial ownership of these indirect positions except to the extent of his pecuniary interest.

Positive

  • None.

Negative

  • None.
Insider SCULLY WILLIAM P
Role null
Bought 50,000 shs ($465K)
Type Security Shares Price Value
Purchase Ordinary Shares, par value $0.01 per share 50,000 $9.3059 $465K
holding Ordinary Shares, par value $0.01 per share -- -- --
holding Ordinary Shares, par value $0.01 per share -- -- --
Holdings After Transaction: Ordinary Shares, par value $0.01 per share — 936,000 shares (Direct, null); Ordinary Shares, par value $0.01 per share — 80,000 shares (Indirect, By Manatee Equity Fund LLC)
Footnotes (1)
  1. The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $9.1000 to $9.4097, inclusive. The reporting person undertakes to provide to Prothena Corp Public Ltd Co, any security holder of Prothena Corp Public Ltd Co, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in footnote (1) to this Form 4. The reporting person disclaims beneficial ownership of these securities except to the extent of his pecuniary interest therein.
Open-market purchase 50,000 shares Ordinary shares bought on June 4, 2026
Purchase price $9.3059 per share Weighted average price for 50,000-share buy
Direct holdings after transaction 936,000 shares Direct ordinary shares following June 4, 2026 trade
Spouse indirect holdings 52,000 shares Ordinary shares held indirectly by spouse
Manatee Equity Fund LLC holdings 80,000 shares Ordinary shares held indirectly via Manatee Equity Fund LLC
Net share change 50,000 shares Net-buy shares from reported transactions
open-market purchase financial
"Purchase in open market or private transaction"
An open-market purchase is when an investor or a company buys shares on a public stock exchange at the going market price, rather than through a private deal. It matters to investors because these purchases change how many shares are available, can push the stock price up or signal confidence from large buyers, and often affect per-share metrics like earnings—think of it like someone buying lots of apples off a grocery shelf, reducing supply and potentially raising the price.
weighted average price financial
"The price reported in Column 4 is a weighted average price."
Weighted average price is the average price of a security where each trade or component is counted according to its size, so bigger trades pull the average more than smaller ones. Think of it like calculating the average cost of a grocery haul where items you bought more of have greater influence on the final per-item cost. Investors use it to understand the true average price paid or received, judge execution quality, and compare trading performance against market movement.
beneficial ownership financial
"The reporting person disclaims beneficial ownership of these securities"
Beneficial ownership means the person or entity that actually enjoys the benefits of owning shares or other assets — such as receiving dividends, voting rights, or price gains — even if the legal title is held in another name. For investors it matters because knowing who truly controls and profits from a company reveals who can influence decisions, exposes potential conflicts of interest or hidden concentration of power, and affects transparency and risk in the stock.
pecuniary interest financial
"except to the extent of his pecuniary interest therein."
indirect ownership financial
"ownership_type": "indirect""
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SEC Form 4
FORM 4UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940
OMB APPROVAL
OMB Number:3235-0287
Estimated average burden
hours per response:0.5
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.
1. Name and Address of Reporting Person*
SCULLY WILLIAM P

(Last)(First)(Middle)
771 MANATEE COVE

(Street)
VERO BEACH FLORIDA 32963

(City)(State)(Zip)

UNITED STATES

(Country)
2. Issuer Name and Ticker or Trading Symbol
PROTHENA CORP PUBLIC LTD CO [ PRTA ]
5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
DirectorX10% Owner
Officer (give title below)Other (specify below)
2a. Foreign Trading Symbol
3. Date of Earliest Transaction (Month/Day/Year)
06/04/2026
6. Individual or Joint/Group Filing (Check Applicable Line)
XForm filed by One Reporting Person
Form filed by More than One Reporting Person
4. If Amendment, Date of Original Filed (Month/Day/Year)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year)2A. Deemed Execution Date, if any (Month/Day/Year)3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4)
CodeVAmount(A) or (D)Price
Ordinary Shares, par value $0.01 per share06/04/2026P50,000A$9.3059(1)936,000D
Ordinary Shares, par value $0.01 per share80,000IBy Manatee Equity Fund LLC(2)
Ordinary Shares, par value $0.01 per share52,000IBy Spouse
Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (Month/Day/Year)3A. Deemed Execution Date, if any (Month/Day/Year)4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 6. Date Exercisable and Expiration Date (Month/Day/Year)7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4)
CodeV(A)(D)Date ExercisableExpiration DateTitleAmount or Number of Shares
Explanation of Responses:
1. The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $9.1000 to $9.4097, inclusive. The reporting person undertakes to provide to Prothena Corp Public Ltd Co, any security holder of Prothena Corp Public Ltd Co, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in footnote (1) to this Form 4.
2. The reporting person disclaims beneficial ownership of these securities except to the extent of his pecuniary interest therein.
Reid E. Buchanan by POA from William P. Scully06/05/2026
** Signature of Reporting PersonDate
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)

FAQ

What insider transaction did William P. Scully report for PROTHENA CORP PUBLIC LTD CO (PRTA)?

William P. Scully reported buying 50,000 Prothena ordinary shares in an open-market transaction. The weighted average price was $9.3059 per share, and the trade occurred on June 4, 2026, increasing his direct ownership stake in the company.

At what price did the Prothena insider buy 50,000 PRTA shares?

The 50,000 Prothena shares were purchased at a weighted average price of $9.3059. Footnotes state the individual trades occurred between $9.10 and $9.4097 per share, with full trade-by-trade details available upon request from the company or the SEC staff.

How many Prothena (PRTA) shares does William P. Scully now hold directly?

After the reported purchase, William P. Scully directly owns 936,000 Prothena ordinary shares. This total reflects his position following the 50,000-share open-market buy disclosed for June 4, 2026, and excludes additional indirect holdings reported separately.

What indirect Prothena shareholdings linked to William P. Scully are disclosed?

The filing reports 52,000 Prothena shares held indirectly through his spouse and 80,000 shares held indirectly through Manatee Equity Fund LLC. Scully disclaims beneficial ownership of these indirect holdings except to the extent of his pecuniary interest in the securities.

Does the Prothena insider Form 4 mention beneficial ownership disclaimers?

Yes. The filing states that William P. Scully disclaims beneficial ownership of certain indirectly held Prothena shares, except for his pecuniary interest. This language clarifies that legal or voting control over some indirectly reported positions may differ from his economic exposure.