[8-K] PROTHENA CORP PUBLIC LTD CO Reports Material Event

Rhea-AI Filing Summary

Prothena Corporation plc reported the results of an extraordinary general meeting of shareholders held on November 19, 2025. Shareholders considered a single proposal to approve a reduction of the Company’s capital to create distributable reserves.

The proposal was approved with 37,779,052 votes in favor, 46,738 against, and 45,906 abstentions. Creating distributable reserves is an Irish corporate law mechanism that can give a company more flexibility to make future distributions, such as dividends or other returns of value, if its board later chooses to do so and other legal requirements are met. This update reflects a change in Prothena’s capital structure authorization rather than an immediate financial transaction.

Insights

Equity Capital Markets Analyst

Prothena shareholders approved a capital reduction to create distributable reserves.

Prothena Corporation plc obtained shareholder approval on November 19, 2025 to reduce its capital to create distributable reserves under Irish law. The vote was overwhelmingly supportive, with 37,779,052 shares voting for the proposal versus 46,738 against and 45,906 abstaining.

Distributable reserves are a key prerequisite for distributions such as dividends or certain forms of capital return. This step does not itself announce any distribution, but it updates the company’s legal capital structure so that, if the board later decides and other conditions are satisfied, it has more flexibility to use accumulated value for shareholder distributions.

From an equity perspective, this is a structural and governance development rather than an immediate earnings or cash-flow event. Its practical implications will depend on any future decisions the board may make regarding dividends, share repurchases, or other forms of return of capital, which are not specified in this update.

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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

_______________________________________________________

FORM 8-K 

_______________________________________________________

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the

Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): November 19, 2025

_______________________________________________________

PROTHENA CORPORATION PUBLIC LIMITED COMPANY

(Exact name of registrant as specified in its charter)

_______________________________________________________

Ireland

001-35676

98-1111119

(State or Other Jurisdiction of Incorporation)

(Commission File Number)

(IRS Employer Identification No.)

77 Sir John Rogerson's Quay, Block C

Grand Canal Docklands

Dublin 2,

D02 VK60,

Ireland

(Address of principal executive offices, including Zip Code)

Registrant’s telephone number, including area code: 011-353-1-236-2500

___________________________________________________

(Former Name or Former Address, if Changed Since Last Report.) 

___________________________________________________

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of Each Class			Trading Symbol			Name of Each Exchange on Which Registered
Ordinary Shares, par value $0.01 per share			PRTA			The Nasdaq Global Select Market

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

                                        Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 5.07. Submission of Matters to a Vote of Security Holders.

On November 19, 2025, Prothena Corporation plc (the “Company”) held an extraordinary general meeting of shareholders, at which the Company’s shareholders voted on the following proposal, which is described in the Company’s definitive proxy statement filed with the Securities and Exchange Commission on October 7, 2025:

Proposal No. 1: Approval of a Reduction of the Company’s Capital to Create Distributable Reserves. The shareholders approved a reduction of the Company’s capital to create distributable reserves.

For						Against						Abstain
37,779,052						46,738						45,906

Item 9.01.    Financial Statements and Exhibits.

(d)    Exhibits

    

Exhibit No.						Description
104						Cover Page Interactive Data File (embedded within the Inline XBRL document)

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

Date:

November 19, 2025

PROTHENA CORPORATION PLC

By:

/s/ Tran B. Nguyen

Name:

Tran B. Nguyen

Title:

Chief Strategy Officer and Chief Financial Officer

FAQ

What did Prothena (PRTA) shareholders approve at the November 19, 2025 meeting?

Shareholders of Prothena Corporation plc approved a reduction of the Company’s capital to create distributable reserves at an extraordinary general meeting held on November 19, 2025.

How did Prothena shareholders vote on the capital reduction proposal?

For the capital reduction proposal, 37,779,052 votes were cast in favor, 46,738 against, and 45,906 abstained, indicating strong support for creating distributable reserves.

Why is creating distributable reserves important for Prothena (PRTA)?

Creating distributable reserves under Irish law can provide Prothena with greater flexibility to make future shareholder distributions, such as dividends or certain capital returns, if its board later decides to do so and all legal requirements are satisfied.

Does this Prothena 8-K mean a new dividend or share buyback is announced?

No specific dividend or share buyback is announced. The update reports shareholder approval of a capital reduction to create distributable reserves, which is a structural step that could allow such actions in the future if the board chooses.

What form did Prothena (PRTA) use to report this shareholder vote?

Prothena reported the shareholder vote on the capital reduction proposal on a Form 8-K under the item covering the submission of matters to a vote of security holders.

Who signed the Prothena report on the shareholder vote?

The report was signed on behalf of Prothena Corporation plc by Tran B. Nguyen, the Company’s Chief Strategy Officer and Chief Financial Officer.