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): March 24, 2026

Commission File Number 001-38103

JANUS HENDERSON GROUP PLC

(Exact name of registrant as specified in its charter)

Jersey, Channel Islands	98-1376360
(State or other jurisdiction of	(I.R.S. Employer
incorporation or organization)	Identification No.)

201 Bishopsgate	EC2M3AE
London, United Kingdom	(Zip Code)
(Address of principal executive offices)

+44 (0) 20 7818 1818

(Registrant’s telephone number, including area code)

N/A

(Former name, former address and former fiscal year, if changed since last report)

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

Title of each class	Trading Symbol(s)	Name of each exchange on which registered
Common Stock, $1.50 Per Share Par Value	JHG	New York Stock Exchange

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))

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. o

Item 17.01 ~~Entry~~Regulation ~~into~~FD ~~a Material Definitive Agreement~~Disclosure.

On March 25, 2026, Janus Henderson Group plc (the “Company”) issued an investor presentation (the “Investor Presentation”) in connection with the previously announced Agreement and Plan of Merger, dated as of December 21, 2025, as amended by that certain Amendment No. 1 to ~~Agreement~~the Agreement and Plan of Merger, dated as of March 24, 2026, by and among the Company, Jupiter Company Limited, a company incorporated in Jersey (“Parent”), and Jupiter Merger Sub Limited, a company incorporated in Jersey and a wholly owned subsidiary of Parent (“Merger Sub”), pursuant to which Merger Sub will merge with and into the Company in accordance with the Companies (Jersey) Law 1991, with the Company continuing as the surviving company and a wholly owned subsidiary of Parent. A copy of the Investor Presentation is furnished as Exhibit 99.1 hereto.

OnThe ~~March~~information ~~24,~~in ~~2026,~~this ~~Janus~~Item ~~Henderson~~7.01 ~~Group~~and ~~plc (the~~Exhibit ~~“Company”),~~99.1 ~~entered~~attached ~~into~~hereto ~~Amendment~~is ~~No.~~intended 1 to ~~the~~be ~~Agreement~~furnished and ~~Plan~~shall ofnot ~~Merger~~be ~~(the~~deemed “~~Amendment~~filed”) ~~with Jupiter~~for ~~Company~~purposes ~~Limited,~~of aSection ~~company~~18 ~~incorporated in Jersey (“Parent”), and Jupiter Merger Sub Limited, a company incorporated in Jersey and a wholly owned subsidiary~~ of ~~Parent (“Merger Sub”), which amends~~ the ~~previously announced Agreement and~~ Securities ~~Plan~~Exchange ofAct ~~Merger, dated as~~ of ~~December 21, 2025~~ 1934 (the “~~Original~~Exchange ~~Merger Agreement~~Act”) ~~and,~~or ~~the Original Merger Agreement as amended, supplemented and~~ otherwise ~~modified~~subject byto the ~~Amendment,~~liabilities ~~the~~of ~~“Amended~~that ~~Merger Agreement”)~~section, ~~pursuant~~nor toshall ~~which Merger~~it ~~Sub~~be ~~will~~deemed ~~merge~~to ~~with~~be ~~and~~incorporated ~~into~~by ~~the~~reference ~~Company (the “Merger”)~~ in ~~accordance~~any ~~with~~filing ~~the~~under ~~Companies (Jersey) Law 1991, with~~ the ~~Company~~ Securities ~~continuing~~Act ~~as the surviving company and a wholly owned subsidiary~~ of ~~Parent.~~1933 or ~~Capitalized~~the Exchange ~~terms~~Act, ~~used~~except ~~but not defined herein shall~~as ~~have~~set ~~the~~forth ~~meanings~~by ~~ascribed~~specific toreference ~~such terms~~ in ~~the~~such ~~Amended Merger Agreement~~filing.

~~Under~~Forward ~~the~~Looking ~~terms of the Amendment, the Company, Parent and Merger Sub have agreed, as compared to the Original Merger Agreement and among other things, to:~~Statements

i.Certain ~~increase~~statements in this Form 8-K not based on historical facts are “forward-looking statements” within the ~~cash~~meaning ~~consideration~~of tothe befederal ~~paid~~securities bylaws. ~~Parent~~Such ~~for~~forward-looking statements ~~each~~involve ~~ordinary~~known ~~share~~and unknown risks and uncertainties that are difficult to predict and could cause our actual results, ~~par~~performance or ~~value~~achievements $1to differ materially from those discussed.50 ~~per~~These ~~share~~include statements as to our future expectations, ofbeliefs, plans, strategies, objectives, events, conditions, financial performance, prospects or future events, including with respect to the ~~Company~~timing ~~(collectively~~and anticipated benefits of pending and recently completed transactions and strategic partnerships, and expectations regarding opportunities that align with our strategy. In some cases, forward-looking statements can be identified by the use of words such as “~~Shares~~may,”) ~~issued~~“could,” “expect,” “intend,” “plan,” “seek,” “anticipate,” “believe,” “estimate,” “predict,” “potential,” “continue,” “likely,” “will,” “would,” and ~~outstanding~~similar ~~immediately~~words ~~prior~~and tophrases. ~~the~~Forward-looking ~~Effective~~statements ~~Time~~are ~~(except~~necessarily ~~for~~based ~~shares~~on ~~held~~estimates and assumptions that, while considered reasonable by ~~Parent~~us and asour ~~otherwise~~management, ~~provided~~are ininherently uncertain. Accordingly, you should not place undue reliance on forward-looking statements, which speak only as of the ~~Amended~~date ~~Merger~~they ~~Agreement)~~are ~~from~~made ~~$49.00~~and toare ~~$52~~not guarantees of future performance.00 ~~per~~We ~~Share~~do innot ~~cash,~~undertake ~~without~~any ~~interest;~~obligation to publicly update or revise these forward-looking statements.

~~ii.~~Various ~~modify~~risks, ~~the~~uncertainties, ~~amount~~assumptions ~~payable~~and factors that could cause our future results to differ materially from those expressed by the ~~Company~~forward-looking ifstatements ~~either~~included ~~Parent~~in orthis Form 8-K include, but are not limited to, the ~~Company~~impact ~~terminates~~of any alternative proposal, Janus Henderson’s ability to obtain the ~~Amended~~regulatory, shareholder ~~Merger~~and ~~Agreement~~other ~~because~~approvals required to consummate the proposed transaction and the timing of the ~~failure~~closing of the proposed transaction, including the risks that a condition to ~~obtain~~closing would not be satisfied within the ~~Required~~expected ~~Company~~timeframe ~~Vote~~or ~~from~~at aall ~~reimbursement~~or that the closing of the ~~certain~~proposed ~~fees~~transaction would not occur, the outcome of any legal proceedings that may be instituted against the parties and ~~expenses~~others ~~actually~~related to ~~incurred~~the bymerger agreement, that shareholder litigation in connection with the proposed transaction may affect the timing or occurrence of the proposed transaction or result in significant costs of defense, indemnification and liability, unanticipated difficulties or expenditures relating to the proposed transaction, including the impact of the transaction on ~~Parent~~Janus Henderson’s ~~behalf~~business, ~~not~~that tothe ~~exceed~~proposed ~~$111~~transaction generally may involve unexpected costs,~~420~~ liabilities or delays,~~000~~ that the business of Janus Henderson may suffer as a result of uncertainty surrounding the proposed transaction or the identity of the purchaser, tothat Janus Henderson may be adversely affected by other economic, business, and/or competitive factors, including the net asset value of assets in certain of Janus Henderson’s funds, and/or potential difficulties in employee retention as a ~~fixed~~result ~~payment~~of the announcement and pendency of ~~$118~~the proposed transaction,~~200~~ changes in interest rates and inflation,~~000~~ changes in trade policies (including the ~~“Expense~~imposition ~~Reimbursement~~of ~~Payment”~~new or increased tariffs);, volatility or disruption in financial markets, our investment performance as compared to third-party benchmarks or competitive products, redemptions, and other risks, uncertainties, assumptions, and factors discussed in our Annual Report on Form 10-K for the year ended December 31, 2025, and in other filings or furnishings made by Janus Henderson with the SEC from time to time.

~~iii.~~Important ~~increase~~Additional ~~the~~Information ~~fees~~and ~~payable by the Company upon termination of the Amended Merger Agreement under specified circumstances (including if the Company terminates the Amended Merger Agreement in order~~ Where to ~~enter~~Find into an alternative transaction that constitutes a Superior Proposal), from (a) $297,130,000 to $394,000,000 if the Expense Reimbursement Payment has not been paid or (b) $222,850,000 to $275,800,000 if the Expense Reimbursement Payment has been paid;It

~~iv.~~In ~~allow~~connection with the ~~Company~~proposed ~~to declare~~transaction, ~~set~~Janus Henderson ~~aside~~Group orplc ~~pay~~(“Janus Henderson”) filed a ~~quarterly~~definitive ~~dividend~~proxy ~~not~~statement towith ~~exceed~~the $1U.00S. ~~per~~Securities ~~share~~and ofExchange ~~Company~~Commission (the ~~Common~~“SEC”) ~~Stock~~on ~~beginning~~March ~~with~~11, ~~fiscal~~2026, ~~quarters~~which ~~commencing~~was first mailed to Janus Henderson’s shareholders on or ~~after~~about ~~July~~March 112, 2026,. ~~with~~Janus ~~declaration~~Henderson and ~~payment~~affiliates ~~dates~~of ~~consistent~~Janus Henderson jointly filed a transaction statement on Schedule 13E-3 on March 11, 2026. Janus Henderson may also file other documents with ~~past~~the ~~practice~~SEC regarding the proposed transaction, ~~and~~including ~~subject~~amendments or supplements to the ~~prior~~proxy statement ~~satisfaction~~or Schedule 13E-3. This communication is not a substitute for the proxy statement, the Schedule 13E-3 or ~~waiver~~any other document that may be filed by ~~Parent~~Janus ofHenderson ~~certain~~with ~~conditions~~the SEC. INVESTORS AND SECURITY HOLDERS OF JANUS HENDERSON ARE URGED TO READ THE PROXY STATEMENT, THE ~~including~~SCHEDULE ~~(but~~13E-3 ~~not~~AND ~~limited~~ANY ~~to)~~OTHER ~~receipt~~RELEVANT DOCUMENTS FILED WITH THE SEC CAREFULLY AND IN THEIR ENTIRETY, BECAUSE THEY CONTAIN OR WILL CONTAIN IMPORTANT INFORMATION. Investors and security holders may obtain the proxy statement and the Schedule 13E-3 and other documents that are filed with the SEC by Janus Henderson free of charge from the ~~(a)~~SEC’s ~~Required~~website ~~Company~~at ~~Vote~~https://www.sec.gov toor ~~approve~~through the ~~Merger~~investor ~~and~~relations section ~~(b)~~of ~~required~~Janus ~~Client~~Henderson’s ~~Consent~~website ~~Percentage;~~at ~~and~~https://ir.janushenderson.com.

v.Participants allow Parent to, following receipt of the Required Company Vote and subject to compliance with Applicable Law, make available to employees of the Company capacity for rollover and other equity purchase and/or participation opportunities, such employees to be identified based on their expressed interest and in ~~consultation with senior management of~~ the ~~Company, provided that no such opportunity shall create any obligation or other liability of the Company prior to the Closing.~~Solicitation

~~The~~Janus ~~foregoing~~Henderson ~~description~~and its directors and certain of ~~the~~its ~~Amendment~~executive officers and other employees may be deemed to be participants in the solicitation of proxies from Janus Henderson’s shareholders in connection with the ~~Amended~~proposed ~~Merger~~transaction. ~~Agreement~~Information ~~does~~about ~~not~~the ~~purport~~directors toand beexecutive aofficers ~~complete~~of ~~statement~~Janus Henderson and their ownership of Janus Henderson common shares is ~~qualified~~contained in ~~its~~the ~~entirety~~definitive byproxy ~~reference~~statement tofor Janus Henderson’s 2025 annual meeting of shareholders (the ~~Amendment~~“Annual Meeting Proxy Statement”), which iswas ~~attached~~filed aswith ~~Exhibit~~the 2.SEC on March 21, 2025, including under the headings “Proposal 1: toElection ~~this~~of ~~Current~~Directors,” ~~Report~~“Corporate onGovernance,” ~~Form~~“Board 8Compensation,” “Proposal 2: Advisory Say-Kon-Pay ~~and~~Vote ~~incorporated~~on ~~herein~~Executive byCompensation,” ~~reference~~“Executive Compensation,” “Executive Compensation Tables,” “Securities Ownership of Certain Beneficial Owners and Management” and “Our Executive Officers.” Additional information regarding the ~~Original~~persons ~~Merger~~who ~~Agreement~~may, under the rules of the SEC, be deemed participants in the solicitation of the shareholders ~~which~~of isJanus ~~attached~~Henderson asin ~~Exhibit~~connection ~~2.1~~with tothe proposed transaction, including a description of their direct or indirect interests, by security holdings or otherwise, has been included in the ~~previously~~definitive ~~filed~~proxy ~~Current~~statement ~~Report~~relating onto ~~Form~~the ~~8-K~~proposed ~~filed~~transaction. To the extent holdings of securities by potential participants (or the ~~Company~~identity onof ~~December~~such 22participants) have changed since the information printed in the Annual Meeting Proxy Statement, ~~2025~~such ~~with~~information has been or will be reflected on the Statements of Change in Ownership of Janus Henderson on ~~Securities~~Forms 3 and ~~Exchange~~4 ~~Commission~~filed with the SEC. Free copies of the proxy statement relating to the proposed transaction and ~~incorporated~~free ~~herein~~copies byof the other SEC filings to which reference is made in this paragraph may be obtained from the SEC’s website at https://www.sec.gov or through the investor relations section of Janus Henderson’s website at https://ir.janushenderson.com.

Item 8.01 Other Events.

On March 24, 2026, the Company issued a press release announcing the signing of the Amendment. A copy of the press release is attached as Exhibit 99.1 to this Current Report on Form 8-K and is incorporated herein by reference.

Forward Looking Statements

Certain statements in this Form 8-K not based on historical facts are “forward-looking statements” within the meaning of the federal securities laws. Such forward-looking statements involve known and unknown risks and uncertainties that are difficult to predict and could cause our actual results, performance or achievements to differ materially from those discussed. These include statements as to our future expectations, beliefs, plans, strategies, objectives, events, conditions, financial performance, prospects or future events, including with respect to the timing and anticipated benefits of pending and recently completed transactions and strategic partnerships, and expectations regarding opportunities that align with our strategy. In some cases, forward-looking statements can be identified by the use of words such as “may,” “could,” “expect,” “intend,” “plan,” “seek,” “anticipate,” “believe,” “estimate,” “predict,” “potential,” “continue,” “likely,” “will,” “would,” and similar words and phrases. Forward-looking statements are necessarily based on estimates and assumptions that, while considered reasonable by us and our management, are inherently uncertain. Accordingly, you should not place undue reliance on forward-looking statements, which speak only as of the date they are made and are not guarantees of future performance. We do not undertake any obligation to publicly update or revise these forward-looking statements.

Various risks, uncertainties, assumptions and factors that could cause our future results to differ materially from those expressed by the forward-looking statements included in this Form 8-K include, but are not limited to, the impact of any alternative proposal, Janus Henderson’s ability to obtain the regulatory, shareholder and other approvals required to consummate the proposed transaction and the timing of the closing of the proposed transaction, including the risks that a condition to closing would not be satisfied within the expected timeframe or at all or that the closing of the proposed transaction would not occur, the outcome of any legal proceedings that may be instituted against the parties and others related to the merger agreement, that shareholder litigation in connection with the proposed transaction may affect the timing or occurrence of the proposed transaction or result in significant costs of defense, indemnification and liability, unanticipated difficulties or expenditures relating to the proposed transaction, including the impact of the transaction on Janus Henderson’s business, that the proposed transaction generally may involve unexpected costs, liabilities or delays, that the business of Janus Henderson may suffer as a result of uncertainty surrounding the proposed transaction or the identity of the purchaser, that Janus Henderson may be adversely affected by other economic, business, and/or competitive factors, including the net asset value of assets in certain of Janus Henderson’s funds, and/or potential difficulties in employee retention as a result of the announcement and pendency of the proposed transaction, changes in interest rates and inflation, changes in trade policies (including the imposition of new or increased tariffs), volatility or disruption in financial markets, our investment performance as compared to third-party benchmarks or competitive products, redemptions, and other risks, uncertainties, assumptions, and factors discussed in our Annual Report on Form 10-K for the year ended December 31, 2025, and in other filings or furnishings made by Janus Henderson with the SEC from time to time.

Important Additional Information and Where to Find It

In connection with the proposed transaction, Janus Henderson Group plc (“Janus Henderson”) filed a definitive proxy statement with the U.S. Securities and Exchange Commission (the “SEC”) on March 11, 2026, which was first mailed to Janus Henderson’s shareholders on or about March 12, 2026. Janus Henderson and affiliates of Janus Henderson jointly filed a transaction statement on Schedule 13E-3 on March 11, 2026. Janus Henderson may also file other documents with the SEC regarding the proposed transaction, including amendments or supplements to the proxy statement or Schedule 13E-3. This communication is not a substitute for the proxy statement, the Schedule 13E-3 or any other document that may be filed by Janus Henderson with the SEC. INVESTORS AND SECURITY HOLDERS OF JANUS HENDERSON ARE URGED TO READ THE PROXY STATEMENT, THE SCHEDULE 13E-3 AND ANY OTHER RELEVANT DOCUMENTS FILED WITH THE SEC CAREFULLY AND IN THEIR ENTIRETY, BECAUSE THEY CONTAIN OR WILL CONTAIN IMPORTANT INFORMATION. Investors and security holders may obtain the proxy statement and the Schedule 13E-3 and other documents that are filed with the SEC by Janus Henderson free of charge from the SEC’s website at https://www.sec.gov or through the investor relations section of Janus Henderson’s website at https://ir.janushenderson.com.

Participants in the Solicitation

Janus Henderson and its directors and certain of its executive officers and other employees may be deemed to be participants in the solicitation of proxies from Janus Henderson’s shareholders in connection with the proposed transaction. Information about the directors and executive officers of Janus Henderson and their ownership of Janus Henderson common shares is contained in the definitive proxy statement for Janus Henderson’s 2025 annual meeting of shareholders (the “Annual Meeting Proxy Statement”), which was filed with the SEC on March 21, 2025, including under the headings “Proposal 1: Election of Directors,” “Corporate Governance,” “Board Compensation,” “Proposal 2: Advisory Say-on-Pay Vote on Executive Compensation,” “Executive Compensation,” “Executive Compensation Tables,” “Securities Ownership of Certain Beneficial Owners and Management” and “Our Executive Officers.” Additional information regarding the persons who may, under the rules of the SEC, be deemed participants in the solicitation of the shareholders of Janus Henderson in connection with the proposed transaction, including a description of their direct or indirect interests, by security holdings or otherwise, has been included in the definitive proxy statement relating to the proposed transaction. To the extent holdings of securities by potential participants (or the identity of such participants) have changed since the information printed in the Annual Meeting Proxy Statement, such information has been or will be reflected on the Statements of Change in Ownership of Janus Henderson on Forms 3 and 4 filed with the SEC. Free copies of the proxy statement relating to the proposed transaction and free copies of the other SEC filings to which reference is made in this paragraph may be obtained from the SEC’s website at https://www.sec.gov or through the investor relations section of Janus Henderson’s website at https://ir.janushenderson.com.

Item 9.01 Financial Statements and Exhibits

(d) Exhibits

The following exhibits ~~listed on the Exhibit Index~~ are ~~incorporated herein~~being byfurnished ~~reference~~herewith.

Exhibit Number		Description
2.1*		Amendment No. 1 to the Agreement and Plan of Merger, dated as of March 24, 2026, by and among Janus Henderson Group plc, Jupiter Company Limited, and Jupiter Merger Sub Limited.
99.1		Janus Henderson Group plc Investor Presentation.
99.1		Press Release, dated as of March 24, 2026.
104		Cover Page Interactive Data File (embedded within the Inline XBRL document).
* Certain schedules and attachments have been omitted pursuant to Item 601(a)(5) of Regulation S-K.

Signature

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: March 2425, 2026

	JANUS HENDERSON GROUP PLC


	By:	/s/ Michelle Rosenberg
	Name:	Michelle Rosenberg
	Title:	General Counsel and Company Secretary

Filing Compare · JANUS HENDERSON GROUP PLC