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): February 1927, 2026

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PROTHENA CORPORATION PUBLIC LIMITED COMPANY

(Exact name of registrant as specified in its charter)

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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 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 27.~~02.~~01 ~~Results~~Regulation ~~of Operations and Financial Condition~~FD.

~~The~~On ~~information~~February in27, ~~Item 2.02~~2026, ofProthena ~~this~~Corporation ~~Current~~plc ~~Report~~(the on"Company") ~~Form~~issued ~~8-K~~a ~~and~~press ~~Exhibit~~release ~~99.1~~announcing ~~attached~~a ~~hereto~~share ~~shall~~repurchase ~~not~~plan beunder ~~deemed~~which ~~“filed”~~the ~~for~~Company ~~purposes~~may ofrepurchase ~~Section 18~~up ofto ~~the~~$100.0 ~~Securities~~million ~~Exchange Act~~ of ~~1934,~~the asCompany's ~~amended~~outstanding ~~(the~~ordinary ~~“Exchange Act”)~~shares, orpar ~~otherwise~~value ~~subject~~$0.01 toper ~~the~~share. ~~liabilities~~A copy of that ~~section.~~press Itrelease ~~may~~is ~~only~~attached beas ~~incorporated~~Exhibit by99.1 ~~reference~~to inthis ~~another~~Current ~~filing~~Report ~~under~~on ~~the~~Form ~~Exchange~~8-K ~~Act~~and oris ~~the~~incorporated ~~Securities~~herein ~~Act of 1933, as amended, if such subsequent filing specifically incorporate~~ by reference ~~the information furnished pursuant to Item 2~~.~~02 (including Exhibit 99.1) of this Current Report.~~

OnThe ~~February 19,~~information ~~2026,~~in ~~Prothena~~Item ~~Corporation~~7.01 ~~plc~~of ~~issued~~this aCurrent ~~press~~Report ~~release~~on ~~announcing~~Form ~~its~~8-K ~~financial~~and ~~results~~Exhibit 99.1 attached hereto shall not be deemed “filed” for purposes of Section 18 of the ~~fourth~~Securities ~~quarter~~Exchange ~~and~~Act ~~fiscal~~of ~~year~~1934, ~~ended~~as ~~December 31~~amended (the “Exchange Act”), ~~2025.~~or Aotherwise ~~copy~~subject to the liabilities of that ~~press~~section. ~~release~~It ismay ~~furnished~~only asbe ~~Exhibit~~incorporated ~~99.1~~by toreference ~~this~~in ~~Current~~another ~~Report~~filing onunder ~~Form~~the ~~8-K~~Exchange ~~and~~Act isor ~~incorporated~~the ~~herein~~Securities Act of 1933, as amended, if such subsequent filing specifically incorporate by reference the information furnished pursuant to Item 7.01 (including Exhibit 99.1) of this Current Report.

Item 98.01. ~~Financial~~Other ~~Statements and Exhibits~~Events.

On February 27, 2026, the Company announced a share repurchase plan under which the Company may repurchase up to $100.0 million of the Company's outstanding ordinary shares, par value $0.01 per share. The share repurchase plan will expire on December 31, 2026, may be suspended or discontinued at any time, and does not obligate the company to acquire any amount of ordinary shares.


Item 9.01			Financial Statements and Exhibits.

(d) Exhibits.

Exhibit No.						Description
99.1						Press Release dated February 1927, 2026
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:

February 1927, 2026

PROTHENA CORPORATION PLC

By:

/s/ Tran B. Nguyen

Name:

Tran B. Nguyen

Title:

Chief ~~Financial~~Strategy Officer and Chief ~~Strategy~~Financial Officer

Filing Compare · PROTHENA CORP PUBLIC LTD CO