Todd Fennell revealed as 10% owner of Prothena

PROTHENA CORP PUBLIC LTD CO (PRTA) reported that Todd W. Fennell filed an initial statement of beneficial ownership on Form 3 as a ten percent owner.

Rhea-AI Filing Summary

PROTHENA CORP PUBLIC LTD CO (PRTA) reported that Todd W. Fennell filed an initial statement of beneficial ownership on Form 3 as a ten percent owner. The filing does not list any specific transactions or current holdings, and shows no reported purchases, sales, or derivative exercises.

Key Figures

Buy transactions: 0 Sell transactions: 0 Derivative exercises: 0 +2 more

5 metrics

Buy transactions 0 Number of reported purchase transactions in this Form 3

Sell transactions 0 Number of reported sale transactions in this Form 3

Derivative exercises 0 Number of derivative exercise transactions in this Form 3

Gift transactions 0 Number of reported gift dispositions in this Form 3

Net buy/sell shares 0 Net shares bought or sold across all reported transactions

Key Terms

ten percent owner, beneficial ownership, Form 3

3 terms

ten percent owner regulatory

"reported as a ten percent owner of PROTHENA"

beneficial ownership regulatory

"filed an initial statement of beneficial ownership on Form 3"

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.

Form 3 regulatory

"filed an initial statement of beneficial ownership on Form 3"

Form 3 is the initial public filing that officers, directors and large shareholders must submit to report their ownership of a company’s securities when they become insiders. It acts like an opening inventory sheet that gives investors a starting point to see who holds significant stakes and to spot later trades or potential conflicts of interest, helping assess insider confidence and transparency.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What does this Form 3 filing mean for PROTHENA (PRTA)?

The Form 3 indicates that Todd W. Fennell is a ten percent owner of PROTHENA. It is an initial disclosure of insider status and does not report any specific stock transactions or current position details.

Did Todd W. Fennell buy or sell PRTA shares in this Form 3?

No transactions are reported in this Form 3. The transaction summary shows 0 buys, 0 sells, and 0 derivative exercises, indicating this filing only establishes insider status, not trading activity.

What insider role is reported for Todd W. Fennell at PROTHENA (PRTA)?

Todd W. Fennell is reported as a ten percent owner of PROTHENA. He is not listed as a director or officer in this filing, and no officer title is provided.

Does this PROTHENA (PRTA) Form 3 show any derivative positions?

The filing reports 0 derivative transactions and an empty derivative position summary. This means no options, warrants, or similar derivative holdings are disclosed in this particular Form 3.

Is there any 10b5-1 trading plan disclosed in this PRTA Form 3?

There is no indication of a Rule 10b5-1 trading plan in this Form 3. The related field is null, and no footnote references a pre-arranged trading plan.

AI-generated analysis. How Rhea-AI works. Not financial advice.

Understanding Insider Trading Forms →

See more from StockTitan in Google Search and AI answers. Adds StockTitan as a preferred source · opens Google

Add on Google Not now

Accepted by SEC EDGAR 08/18/2026 - 04:16 PM EDT Learn about SEC filing dates

SEC Form 3

FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

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:			3235-0104
Estimated average burden
hours per response:			0.5

1. Name and Address of Reporting Person^*

Fennell Todd W.

(Last) (First) (Middle)

979 BEACHLAND BOULEVARD

(Street)

VERO BEACH FLORIDA 32963

(City) (State) (Zip)

UNITED STATES

(Country)

2. Date of Event Requiring Statement (Month/Day/Year)
08/18/2026

3. Issuer Name and Ticker or Trading Symbol
PROTHENA CORP PUBLIC LTD CO [ PRTA ]

3a. Foreign Trading Symbol

5. If Amendment, Date of Original Filed (Month/Day/Year)

4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director	X	10% Owner
	Officer (give title below)		Other (specify below)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

No securities are beneficially owned.

	Reid E. Buchanan by POA from Todd W. Fennell	08/18/2026
	** Signature of Reporting Person	Date
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 5 (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 3: SEC 1473 (03-26)