Definitive Materials Filed by Investment Companies. (497)

Janus Investment Fund

Janus Diversified Alternatives Fund

Supplement dated June 28, 2013

to Currently Effective Prospectuses

The following replaces in its entirety the corresponding information under “Availability of Portfolio Holdings Information” found in the Shareholder’s Guide (or Shareholder’s Manual if you hold Class D Shares) of the Prospectus.

AVAILABILITY OF PORTFOLIO HOLDINGS INFORMATION

The Mutual Fund Holdings Disclosure Policies and Procedures adopted by Janus Capital and all mutual funds managed within the Janus fund complex are designed to be in the best interests of the funds and to protect the confidentiality of the funds’ portfolio holdings. The following describes policies and procedures with respect to disclosure of portfolio holdings.


	•	*Full Holdings.* The Fund is required to disclose its complete holdings in the quarterly holdings report on Form N-Q within 60 days of the end of the first and third fiscal quarters, and in the annual report and semiannual report to Fund shareholders. These reports (i) are available on the SEC’s website at http://www.sec.gov; (ii) may be reviewed and copied at the SEC’s Public Reference Room in Washington, D.C. (information on the Public Reference Room may be obtained by calling 1-800-SEC-0330); and (iii) are available without charge, upon request, by calling a Janus representative at 1-800-525-0020 (toll free). Portfolio holdings, consisting of the names of the holdings in alphabetical order, are generally available on a calendar quarter-end basis with a 60-day lag. Holdings are generally posted approximately two business days thereafter under Full Holdings for the Fund at janus.com/info (or, if applicable, under the Fund’s Holdings & Details tab at janus.com/allfunds if you hold Class D Shares).

The Fund may provide, upon request, historical full holdings on a monthly basis for periods prior to the previous quarter-end subject to a written confidentiality agreement, subject to preapproval of the Chief Compliance Officer and the Fund’s portfolio managers.


	•	*Top Holdings.* The Fund’s top portfolio holdings, consisting of security names only in alphabetical order and determined according to their notional value, are generally available monthly with a 15-day lag and on a calendar quarter-end basis with a 15-day lag.

	•	*Other Information.* Upon request only, the Fund may provide security breakdowns (e.g., industry, sector, regional, market capitalization, risk premia basket, and asset allocation), and portfolio level performance contribution information and statistics monthly with a 15-day lag and on a calendar quarter-end basis with a 15-day lag. Top performance contributors/detractors, consisting of security names in alphabetical order, are generally available monthly with a 15-day lag and on a calendar quarter-end basis with a 15-day lag.

Full portfolio holdings will remain available on the Janus websites at least until a Form N-CSR or Form N-Q is filed with the SEC for the period that includes the date as of which the website information is current. Janus Capital may exclude from publication on its websites all or any portion of portfolio holdings or change the time periods of disclosure as deemed necessary to protect the interests of the Janus funds. Under extraordinary circumstances, exceptions to the Mutual Fund Holdings Disclosure Policies and Procedures may be made by Janus Capital’s Chief Investment Officer(s) or their delegates. All exceptions shall be preapproved by the Chief Compliance Officer or his designee. Such exceptions may be made without prior notice to shareholders. A summary of the Fund’s portfolio holdings disclosure policies and procedures, which includes a discussion of any exceptions, is contained in the Fund’s statement of additional information.

Please retain this Supplement with your records.

Janus Investment Fund

Janus Diversified Alternatives Fund

Supplement dated June 28, 2013

to Currently Effective Statement of Additional Information

The following replaces in their entirety the corresponding paragraphs and bullet points found under the “Portfolio Holdings Disclosure Policies and Procedures” section of the Statement of Additional Information.

PORTFOLIO HOLDINGS DISCLOSURE POLICIES AND PROCEDURES


	•	*Full Holdings.* The Fund is required to disclose its complete holdings in the quarterly holdings report on Form N-Q within 60 days of the end of the first and third fiscal quarters, and in the annual report and semiannual report to Fund shareholders. These reports (i) are available on the SEC’s website at http://www.sec.gov; (ii) may be reviewed and copied at the SEC’s Public Reference Room in Washington, D.C. (information on the Public Reference Room may be obtained by calling 1-800-SEC-0330); and (iii) are available without charge, upon request, by calling a Janus representative at 1-800-525-0020 (toll free). Portfolio holdings, consisting of the names of the holdings in alphabetical order, are generally available on a calendar quarter-end basis with a 60-day lag. Holdings are generally posted approximately two business days thereafter under Full Holdings for the Fund at janus.com/info.


	•	*Top Holdings.* The Fund’s top portfolio holdings, consisting of security names only in alphabetical order and determined according to their notional value, are generally available monthly with a 15-day lag and on a calendar quarter-end basis with a 15-day lag.

	•	*Other Information.* Upon request only, the Fund may provide security breakdowns (e.g., industry, sector, regional, market capitalization, risk premia basket, and asset allocation), and portfolio level performance contribution information and statistics monthly with a 15-day lag and on a calendar quarter-end basis with a 15-day lag. Top performance contributors/detractors, consisting of security names in alphabetical order, are generally available monthly with a 15-day lag and on a calendar quarter-end basis with a 15-day lag.