# EDGAR Filing Document

**Accession Number:** 0000277751
**File Stem:** 0001193125-23-016491
**Filing Date:** 2023-1
**Character Count:** 48638
**Document Hash:** 61b31e52850ab612a6a0f04b6e7aefba
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001193125-23-016491.hdr.sgml**: 20230127

**ACCESSION NUMBER**: 0001193125-23-016491

**CONFORMED SUBMISSION TYPE**: 497K

**PUBLIC DOCUMENT COUNT**: 3

**FILED AS OF DATE**: 20230127

**DATE AS OF CHANGE**: 20230126

**EFFECTIVENESS DATE**: 20230127

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** JANUS INVESTMENT FUND
- **CENTRAL INDEX KEY:** 0000277751
- **IRS NUMBER:** 840592523
- **STATE OF INCORPORATION:** MA

**FILING VALUES:**
- **FORM TYPE:** 497K
- **SEC ACT:** 1933 Act
- **SEC FILE NUMBER:** 002-34393
- **FILM NUMBER:** 23559108

**BUSINESS ADDRESS:**
- **STREET 1:** 151 DETROIT STREET
- **CITY:** DENVER
- **STATE:** CO
- **ZIP:** 80206
- **BUSINESS PHONE:** 303-333-3863

**MAIL ADDRESS:**
- **STREET 1:** 151 DETROIT STREET
- **CITY:** DENVER
- **STATE:** CO
- **ZIP:** 80206

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** JANUS FUND /MD/
- **DATE OF NAME CHANGE:** 19870701

## Series and Classes Contracts Data

### Janus Henderson Triton Fund (Series ID: S000010485)

| Class ID   | Class Name   | Ticker Symbol   |
|:---|:---|:---|
| C000028947 | Class T      | JATTX           |
| C000077722 | Class A      | JGMAX           |
| C000077723 | Class C      | JGMCX           |
| C000077724 | Class I      | JSMGX           |
| C000077725 | Class R      | JGMRX           |
| C000077726 | Class S      | JGMIX           |
| C000083530 | Class D      | JANIX           |
| C000114880 | Class N      | JGMNX           |

[JANUS HENDERSON LOGO]

**Janus Henderson Triton Fund** 

Ticker: JGMAX Class A Shares JGMIX Class S Shares JGMNX Class N Shares JATTX Class T Shares <br> JGMCX Class C Shares JSMGX Class I Shares JGMRX Class R Shares

**Summary Prospectus dated January 27, 2023**

***Before you invest, you may want to review the Fund's Prospectus, which contains more information about the Fund and its risks. You can find the Fund's Prospectus, reports to shareholders, and other information about the Fund online at janushenderson.com/info. You can also get this information at no cost by calling a Janus Henderson representative at 1-877-335-2687 or by sending an email request to prospectusrequest@janushenderson.com.***

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**Investment Objective**<br>

**Janus Henderson Triton Fund** seeks long-term growth of capital.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

**Fees and Expenses of the Fund**<br>

This table describes the fees and expenses that you may pay if you buy, hold, and sell Shares of the Fund. Each share class has different expenses, but represents an investment in the same Fund. For Class A Shares, you may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $50,000 in the Fund or in other Janus Henderson funds. More information about these and other discounts, as well as eligibility requirements for each share class, is available from your financial professional and in the "Purchases" section on page 97 of the Fund's Prospectus and in the "Purchases" section on page 79 of the Fund's Statement of Additional Information. In addition, please see Appendix A – Intermediary Sales Charge Waivers and Discounts. You may also incur brokerage commissions charged by your broker or financial intermediary when buying Class I Shares or Class N Shares of the Fund that are not reflected in the table or in the example below.

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| | | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|:---|
| **SHAREHOLDER FEES**<br> (fees paid directly from your investment)<br>| **Class A** | **Class C** | **Class S** | **Class I** | **Class N** | **Class R** | **Class T** |
| &nbsp;&nbsp;&nbsp;&nbsp; Maximum Sales Charge (load) Imposed on Purchases (as a <br> percentage of offering price)<br>| 5.75% |  |  |  |  |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp; Maximum Deferred Sales Charge (load) (as a percentage of <br> the lower of original purchase price or redemption <br> proceeds)<br>|  | 1.00% |  |  |  |  |  |
| **ANNUAL FUND OPERATING EXPENSES**<br> (expenses that you pay each year as a percentage of the value <br> of your investment)<br>| **Class A** | **Class C** | **Class S** | **Class I** | **Class N** | **Class R** | **Class T** |
| Management Fees | 0.64% | 0.64% | 0.64% | 0.64% | 0.64% | 0.64% | 0.64% |
| Distribution/Service (12b-1) Fees | 0.25% | 1.00% | 0.25% |  |  | 0.50% |  |
| Other Expenses | 0.41% | 0.10% | 0.27% | 0.12% | 0.02% | 0.28% | 0.27% |
| Total Annual Fund Operating Expenses | 1.30% | 1.74% | 1.16% | 0.76% | 0.66% | 1.42% | 0.91% |

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**EXAMPLE:**

The Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and reinvest all dividends and distributions. The Example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same. Class C Shares automatically convert to Class A Shares after eight years. The Example for Class C Shares for the ten-year period reflects the conversion to Class A Shares. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

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| | | | | |
|:---|:---|:---|:---|:---|
| **If Shares are redeemed:** | **1 Year** | **3 Years** | **5 Years** | **10 Years** |
| Class A Shares | $700 | $963 | $1247  | $2053 |
| Class C Shares | $277 | $548 | $944 | $1936 |
| Class S Shares | $118 | $368 | $638 | $1409 |
| Class I Shares | $78 | $243 | $422 | $942 |
| Class N Shares | $67 | $211 | $368 | $822 |

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1 \| Janus Henderson Triton Fund

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| | | | | |
|:---|:---|:---|:---|:---|
| **If Shares are redeemed:** | **1 Year** | **3 Years** | **5 Years** | **10 Years** |
| Class R Shares | $145 | $449 | $776 | $1702 |
| Class T Shares | $93 | $290 | $504 | $1120 |

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| | | | | |
|:---|:---|:---|:---|:---|
| **If Shares are not redeemed:** | **1 Year** | **3 Years** | **5 Years** | **10 Years** |
| Class A Shares | $700 | $963 | $1247  | $2053 |
| Class C Shares | $177 | $548 | $944 | $1936 |
| Class S Shares | $118 | $368 | $638 | $1409 |
| Class I Shares | $78 | $243 | $422 | $942 |
| Class N Shares | $67 | $211 | $368 | $822 |
| Class R Shares | $145 | $449 | $776 | $1702 |
| Class T Shares | $93 | $290 | $504 | $1120 |

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**Portfolio Turnover:** The Fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the Example, affect the Fund's performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 8% of the average value of its portfolio.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

**Principal investment strategies**<br>

The Fund pursues its investment objective by investing at least 50% of its equity assets in small- and medium-sized companies. The Fund may also invest in larger companies with strong growth potential. Small- and medium-sized companies are defined by the portfolio managers as those companies whose market capitalization falls within the range of companies in the Russell 2500<sup>tm</sup> Growth Index at the time of initial purchase. Market capitalization is a commonly used measure of the size and value of a company. The market capitalizations within the index will vary, but as of September 30, 2022, they ranged from approximately $4 million to $18.09 billion. The Fund may invest in shares of companies through initial public offerings and secondary offerings.

The portfolio managers apply a "bottom up" approach in choosing investments. In other words, the portfolio managers look at companies one at a time to determine if a company is an attractive investment opportunity and if it is consistent with the Fund's investment policies. Factors that the portfolio managers may consider in their fundamental analysis include a company's valuation, operating margins, or returns on capital. The portfolio managers will generally consider selling a position when, among other things, there is a deterioration in a company's competitive position or financials, a company reaches or exceeds its targeted value, or if a company's market capitalization exceeds the top of the small- and medium-sized range.

The Fund may also invest in foreign securities, which may include investments in emerging markets.

The Fund may seek to earn additional income through lending its securities to certain qualified broker-dealers and institutions on a short-term or long-term basis, in an amount equal to up to one-third of its total assets as determined at the time of the loan origination.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

**Principal investment risks**<br>

The biggest risk is that the Fund's returns will vary, and you could lose money. The Fund is designed for long-term investors seeking an equity portfolio, including common stocks. Common stocks tend to be more volatile than many other investment choices. The principal risks associated with investing in the Fund are set forth below.

***Market Risk.*** The value of the Fund's portfolio may decrease due to short-term market movements and over more prolonged market downturns. As a result, the Fund's net asset value may fluctuate and it may be more difficult to value or sell the Fund's holdings. Market risk may affect a single issuer, industry, economic sector, or the market as a whole. Market risk may be magnified if certain social, political, economic, and other conditions and events (such as terrorism, conflicts, including related sanctions, social unrest, natural disasters, epidemics and pandemics, including COVID-19) adversely interrupt the global economy and financial markets. It is important to understand that the value of your investment may fall, sometimes sharply, in response to changes in the market, and you could lose money.

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***Portfolio Management Risk.*** The Fund is an actively managed investment portfolio and is therefore subject to the risk that the investment strategies and research process employed for the Fund may fail to produce the intended results. The Fund may underperform its benchmark index or other mutual funds with similar investment objectives.

***Small- and Mid-Sized Companies Risk.*** Investments in securities issued by small- and mid-sized companies, which can include smaller, start-up companies offering emerging products or services, may involve greater risks than are customarily associated with larger, more established companies. For example, while small- and mid-sized companies may realize more substantial growth than larger or more established issuers, they may also suffer more significant losses as a result of their narrow product lines, limited operating history, greater exposure to competitive threats, limited financial resources, limited trading markets, and the potential lack of management depth. Securities issued by small- and mid-sized companies tend to be more volatile and somewhat more speculative than securities issued by larger or more established companies and may underperform as compared to the securities of larger or more established companies. These holdings are also subject to wider price fluctuations and tend to be less liquid than stocks of larger or more established companies, which could have a significant adverse effect on the Fund's returns, especially as market conditions change.

***Growth Securities Risk.*** Securities of companies perceived to be "growth" companies may be more volatile than other stocks and may involve special risks. If the portfolio managers' perception of a company's growth potential is not realized, the securities purchased may not perform as expected, reducing the Fund's returns. In addition, because different types of stocks tend to shift in and out of favor depending on market and economic conditions, "growth" stocks may perform differently from the market as a whole and other types of securities.

***Industry and Sector Risk.*** Although the Fund does not concentrate its investments in specific industries or sectors, it may have a significant portion of its assets invested in securities of companies conducting similar business, or business within the same economic sector. Companies in the same industry or economic sector may be similarly affected by economic or market events, making the Fund more vulnerable to unfavorable developments than funds that invest more broadly. As the Fund's portfolio becomes more concentrated, the Fund is less able to spread risk and potentially reduce the risk of loss and volatility. In addition, the Fund may be overweight or underweight in certain industries or sectors relative to its benchmark index, which may cause the Fund's performance to be more or less sensitive to developments affecting those sectors.

***Initial Public Offering and Secondary Offering Risk.*** Initial public offerings ("IPOs") and secondary offering shares frequently are volatile in price due to the absence of a prior public market, the small number of shares available for trading, and limited information about the issuer. Therefore, the Fund may hold IPO and secondary offering shares for a very short period of time. This may increase the portfolio turnover rate of the Fund and may lead to increased expenses for the Fund, such as commissions and transaction costs. Although IPOs and secondary offerings may have had a positive impact on the Fund's performance in the past, there can be no assurance that the Fund will identify favorable IPO and secondary offering investment opportunities in the future. In addition, as the Fund increases in size, the impact of IPOs and secondary offerings on the Fund's performance will generally decrease.

***Foreign Exposure Risk.*** Foreign markets, including emerging markets, can be more volatile than the U.S. market. As a result, the Fund's returns and net asset value may be affected by fluctuations in currency exchange rates or political or economic conditions in a particular country. In some foreign markets, there may not be protection against failure by other parties to complete transactions. It may not be possible for the Fund to repatriate capital, dividends, interest, and other income from a particular country or governmental entity. In addition, a market swing in one or more countries or regions where the Fund has invested a significant amount of its assets may have a greater effect on the Fund's performance than it would in a more geographically diversified portfolio. The Fund's investments in emerging market countries, if any, may involve risks greater than, or in addition to, the risks of investing in more developed countries.

***Securities Lending Risk.*** There is the risk that when portfolio securities are lent, the securities may not be returned on a timely basis, and the Fund may experience delays and costs in recovering the security or gaining access to the collateral provided to the Fund to collateralize the loan. If the Fund is unable to recover a security on loan, the Fund may use the collateral to purchase replacement securities in the market. There is a risk that the value of the collateral could decrease below the cost of the replacement security by the time the replacement investment is made, resulting in a loss to the Fund.

*An investment in the Fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.*

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

3 \| Janus Henderson Triton Fund

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**Performance information**<br>

The following information provides some indication of the risks of investing in the Fund by showing how the Fund's performance has varied over time. Class T Shares (formerly named Class J Shares, the initial share class) of the Fund commenced operations with the Fund's inception. Class A Shares, Class C Shares, Class S Shares, Class I Shares, and Class R Shares of the Fund commenced operations on July 6, 2009. Class N Shares of the Fund commenced operations on May 31, 2012.

• The performance shown for Class T Shares is calculated using the fees and expenses of Class T Shares in effect during the periods shown, net of any applicable fee and expense limitations or waivers.

• The performance shown for Class A Shares, Class C Shares, Class S Shares, and Class R Shares for periods prior to July 6, 2009, reflects the performance of the Fund's former Class J Shares, calculated using the fees and expenses of each respective share class, without the effect of any fee and expense limitations or waivers.

• The performance shown for Class I Shares for periods prior to July 6, 2009, reflects the performance of the Fund's former Class J Shares, calculated using the fees and expenses of Class J Shares, net of any applicable fee and expense limitations or waivers.

• The performance shown for Class N Shares for periods prior to May 31, 2012, reflects the performance of the Fund's Class T Shares, calculated using the fees and expenses of Class T Shares, net of any applicable fee and expense limitations or waivers.

If Class A Shares, Class C Shares, Class S Shares, Class I Shares, and Class R Shares of the Fund had been available during periods prior to July 6, 2009, or Class N Shares of the Fund had been available during periods prior to May 31, 2012, the performance shown for each respective share class may have been different. The performance shown for the periods following the Fund's commencement of Class A Shares, Class C Shares, Class S Shares, Class I Shares, Class N Shares, and Class R Shares reflects the fees and expenses of each respective share class, net of any applicable fee and expense limitations or waivers.

The bar chart depicts the change in performance from year to year during the periods indicated. The bar chart figures do not include any applicable sales charges that an investor may pay when they buy or sell Class A Shares or Class C Shares of the Fund. If sales charges were included, the returns would be lower. The table compares the Fund's average annual returns for the periods indicated to a broad-based securities market index, as well as to one or more supplemental indices that have investment characteristics similar to those of the Fund. All figures assume reinvestment of dividends and distributions. For certain periods, the Fund's performance reflects the effect of expense waivers. Without the effect of these expense waivers, the performance shown would have been lower.

*The Fund's past performance (before and after taxes) does not necessarily indicate how it will perform in the future. Updated performance information is available at janushenderson.com/performance or by calling 1-877-335-2687*.

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| |
|:---|
| **Annual Total Returns for Class T Shares** (calendar year-end) |
| &nbsp;&nbsp; ![](g86839imgffb75f3e1.jpg)<br>|

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

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| | | | | | |
|:---|:---|:---|:---|:---|:---|
| **Best Quarter:** | 2nd Quarter 2020 | **29.43%** | **Worst Quarter:** | 1st Quarter 2020 | **– 27.86%** |

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4 \| Janus Investment Fund

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| | | | | |
|:---|:---|:---|:---|:---|
| **Average Annual Total Returns** (periods ended 12/31/22) |  |  |  |  |
|  | **1 Year** | **5 Years** | **10 Years** | &nbsp;&nbsp; **Since** <br> **Inception**<br> **(2/25/05)**<br>|
| **Class T Shares** |  |  |  |  |
| Return Before Taxes | – 23.77% | 4.93% | 10.40% | 10.79% |
| Return After Taxes on Distributions | – 24.87% | 2.86% | &nbsp;&nbsp; 8.57% | &nbsp;&nbsp; 9.40% |
| Return After Taxes on Distributions and Sale of Fund Shares<sup>(1)</sup> <br>| – 13.31% | 3.85% | &nbsp;&nbsp; 8.36% | &nbsp;&nbsp; 9.02% |
| &nbsp;&nbsp;&nbsp;&nbsp; Russell 2500<sup>TM</sup> Growth Index<br> (reflects no deduction for expenses, fees, or taxes)<br>| – 26.21% | 5.97% | 10.62% | &nbsp;&nbsp; 8.80% |
| &nbsp;&nbsp;&nbsp;&nbsp; Russell 2000<sup>®</sup> Growth Index<br> (reflects no deduction for expenses, fees, or taxes)<br>| – 26.36% | 3.51% | &nbsp;&nbsp; 9.20% | &nbsp;&nbsp; 7.63% |
| **Class A Shares** |  |  |  |  |
| Return Before Taxes<sup>(2)</sup> <br>| – 28.30% | 3.47% | &nbsp;&nbsp; 9.52% | 10.22% |
| &nbsp;&nbsp;&nbsp;&nbsp; Russell 2500<sup>TM</sup> Growth Index<br> (reflects no deduction for expenses, fees, or taxes)<br>| – 26.21% | 5.97% | 10.62% | &nbsp;&nbsp; 8.80% |
| &nbsp;&nbsp;&nbsp;&nbsp; Russell 2000<sup>®</sup> Growth Index<br> (reflects no deduction for expenses, fees, or taxes)<br>| – 26.36% | 3.51% | &nbsp;&nbsp; 9.20% | &nbsp;&nbsp; 7.63% |
| **Class C Shares** |  |  |  |  |
| Return Before Taxes<sup>(3)</sup> <br>| – 24.93% | 4.15% | &nbsp;&nbsp; 9.52% | &nbsp;&nbsp; 9.86% |
| &nbsp;&nbsp;&nbsp;&nbsp; Russell 2500<sup>TM</sup> Growth Index<br> (reflects no deduction for expenses, fees, or taxes)<br>| – 26.21% | 5.97% | 10.62% | &nbsp;&nbsp; 8.80% |
| &nbsp;&nbsp;&nbsp;&nbsp; Russell 2000<sup>®</sup> Growth Index<br> (reflects no deduction for expenses, fees, or taxes)<br>| – 26.36% | 3.51% | &nbsp;&nbsp; 9.20% | &nbsp;&nbsp; 7.63% |
| **Class S Shares** |  |  |  |  |
| Return Before Taxes | – 23.94% | 4.66% | 10.12% | 10.49% |
| &nbsp;&nbsp;&nbsp;&nbsp; Russell 2500<sup>TM</sup> Growth Index<br> (reflects no deduction for expenses, fees, or taxes)<br>| – 26.21% | 5.97% | 10.62% | &nbsp;&nbsp; 8.80% |
| &nbsp;&nbsp;&nbsp;&nbsp; Russell 2000<sup>®</sup> Growth Index<br> (reflects no deduction for expenses, fees, or taxes)<br>| – 26.36% | 3.51% | &nbsp;&nbsp; 9.20% | &nbsp;&nbsp; 7.63% |
| **Class I Shares** |  |  |  |  |
| Return Before Taxes | – 23.63% | 5.08% | 10.57% | 10.93% |
| &nbsp;&nbsp;&nbsp;&nbsp; Russell 2500<sup>TM</sup> Growth Index<br> (reflects no deduction for expenses, fees, or taxes)<br>| – 26.21% | 5.97% | 10.62% | &nbsp;&nbsp; 8.80% |
| &nbsp;&nbsp;&nbsp;&nbsp; Russell 2000<sup>®</sup> Growth Index<br> (reflects no deduction for expenses, fees, or taxes)<br>| – 26.36% | 3.51% | &nbsp;&nbsp; 9.20% | &nbsp;&nbsp; 7.63% |
| **Class N Shares** |  |  |  |  |
| Return Before Taxes | – 23.58% | 5.18% | 10.68% | 10.95% |
| &nbsp;&nbsp;&nbsp;&nbsp; Russell 2500<sup>TM</sup> Growth Index<br> (reflects no deduction for expenses, fees, or taxes)<br>| – 26.21% | 5.97% | 10.62% | &nbsp;&nbsp; 8.80% |
| &nbsp;&nbsp;&nbsp;&nbsp; Russell 2000<sup>®</sup> Growth Index<br> (reflects no deduction for expenses, fees, or taxes)<br>| – 26.36% | 3.51% | &nbsp;&nbsp; 9.20% | &nbsp;&nbsp; 7.63% |
| **Class R Shares** |  |  |  |  |
| Return Before Taxes | – 24.12% | 4.41% | &nbsp;&nbsp; 9.85% | 10.24% |
| &nbsp;&nbsp;&nbsp;&nbsp; Russell 2500<sup>TM</sup> Growth Index<br> (reflects no deduction for expenses, fees, or taxes)<br>| – 26.21% | 5.97% | 10.62% | &nbsp;&nbsp; 8.80% |
| &nbsp;&nbsp;&nbsp;&nbsp; Russell 2000<sup>®</sup> Growth Index<br> (reflects no deduction for expenses, fees, or taxes)<br>| – 26.36% | 3.51% | &nbsp;&nbsp; 9.20% | &nbsp;&nbsp; 7.63% |

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(1) If the Fund incurs a loss, which generates a tax benefit, the Return After Taxes on Distributions and Sale of Fund Shares may exceed the Fund's other return figures.

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

(2) Calculated assuming maximum permitted sales loads.

(3) The one year return is calculated to include the contingent deferred sales charge.

The Fund's primary benchmark index is the Russell 2500 Growth Index. The Fund also compares its performance to the Russell 2000 Growth Index. The indices are described below.

• The Russell 2500 Growth Index measures the performance of those Russell 2500 companies with higher price-to-book ratios and higher forecasted growth values.

• The Russell 2000 Growth Index measures the performance of those Russell 2000 companies with higher price-to-book ratios and higher forecasted growth values.

After-tax returns are calculated using distributions for the Fund's Class T Shares (formerly named Class J Shares, the initial share class). After-tax returns are calculated using the historically highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on your individual tax situation and may differ from those shown in the preceding table. The after-tax return information shown above does not apply to Fund shares held through a tax-advantaged account, such as a 401(k) plan or an IRA.

After-tax returns are only shown for Class T Shares of the Fund. After-tax returns for the other classes of Shares will vary from those shown for Class T Shares due to varying sales charges (as applicable), fees, and expenses among the classes.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

**Management**<br>

**Investment Adviser:** Janus Henderson Investors US LLC

**Portfolio Managers: Jonathan D. Coleman**, CFA, is Executive Vice President and Lead Portfolio Manager of the Fund, which he has managed or co-managed since May 2013. **Scott Stutzman**, CFA, is Executive Vice President and Co-Portfolio Manager of the Fund, which he has co-managed since July 2016.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

**Purchase and sale of Fund shares**<br>

**Minimum Investment Requirements** 

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| | |
|:---|:---|
| **Class A Shares, Class C Shares**\***, Class S Shares, Class R Shares, and Class T Shares** |  |
| Non-retirement accounts | $2,500\*\* |
| Certain tax-advantaged accounts or UGMA/UTMA accounts | $500 |
| **Class I Shares** |  |
| Institutional investors (investing directly with the Fund) | $1000000 |
| Through an intermediary institution |  |
| &nbsp;&nbsp;&nbsp;&nbsp; • non-retirement accounts | $2,500† |
| &nbsp;&nbsp;&nbsp;&nbsp; • certain tax-advantaged accounts or UGMA/UTMA accounts | $500† |
| **Class N Shares** |  |
| Retirement investors (investing through an adviser-assisted, employer-sponsored retirement plan) |  |
| Retail investors (investing through a financial intermediary omnibus account) | $2,500\*\*\* |
| Institutional investors (investing directly with the Fund) | $1000000 |

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†

Exceptions to these minimums may apply for certain tax-advantaged, tax-qualified and retirement plans, including health savings accounts, accounts held through certain wrap programs, and certain retail brokerage accounts.

\*

The maximum purchase in Class C Shares is $500,000 for any single purchase.

\*\*

Class A, Class C, Class S, and Class T shares held through certain supermarket and/or self-directed brokerage accounts, or through wrap programs, may not be subject to these minimums. Please contact your financial intermediary for more information. For Class R shareholders, there is no investment minimum for defined contribution plans. Investors in a defined contribution plan through a third party administrator should refer to their plan document or contact their plan administrator for additional information regarding account minimums. <br>

\*\*\*

Investors in certain tax-advantaged accounts or accounts held through certain wrap programs or bank trust platforms may not be subject to this minimum.

Purchases, exchanges, and redemptions can generally be made only through institutional channels, such as financial intermediaries and retirement platforms. Class I Shares may be purchased directly by certain institutional investors who established Class I Shares accounts before August 4, 2017. You should contact your financial intermediary or refer to your

6 \| Janus Investment Fund

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plan documents for information on how to invest in the Fund. Requests must be received in good order by the Fund or its agents (financial intermediary or plan sponsor, if applicable) prior to the close of the trading session of the New York Stock Exchange in order to receive that day's net asset value. For additional information, refer to "Purchases," "Exchanges," and/or "Redemptions" in the Prospectus.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

**Tax information**<br>

The Fund's distributions are taxable, and will be taxed as ordinary income or capital gains, unless you are investing through a tax-advantaged arrangement, such as a 401(k) plan or an individual retirement account (in which case you may be taxed upon withdrawal of your investment from such account).

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

**Payments to broker-dealers and other financial intermediaries**<br>

If you purchase Class A Shares, Class C Shares, Class S Shares, Class I Shares, Class R Shares, or Class T Shares of the Fund through a broker-dealer or other financial intermediary (such as a bank), the Fund or its distributor (or its affiliates) may pay the intermediary for the sale of Fund shares and related services. These payments may create a conflict of interest by influencing the broker-dealer or other intermediary and your salesperson to recommend the Fund over another investment or to recommend one share class over another. There is some regulatory uncertainty concerning whether marketing support or other similar payments may be made or received in connection with Class I Shares where a financial intermediary has imposed its own sales charges or transaction fees. As a result, based on future regulatory developments, such payments may be terminated, or the Fund may prohibit financial intermediaries from imposing such sales charges or transaction fees in connection with Class I Shares. Ask your salesperson or visit your financial intermediary's website for more information.

7 \| Janus Henderson Triton Fund

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[JANUS HENDERSON LOGO]

**Janus Henderson Triton Fund** 

Ticker: JANIX Class D Shares

**Summary Prospectus dated January 27, 2023**

***Before you invest, you may want to review the Fund's Prospectus, which contains more information about the Fund and its risks. You can find the Fund's Prospectus, reports to shareholders, and other information about the Fund online at janushenderson.com/reports. You can also get this information at no cost by calling a Janus Henderson representative at 1-800-525-3713 or by sending an email request to prospectusorder@janushenderson.com.***

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**Investment Objective**<br>

**Janus Henderson Triton Fund** seeks long-term growth of capital.

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**Fees and Expenses of the Fund**<br>

This table describes the fees and expenses that you may pay if you buy, hold, and sell Shares of the Fund.

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| | |
|:---|:---|
| **ANNUAL FUND OPERATING EXPENSES**<br> (expenses that you pay each year as a percentage of the value of your investment)<br>| **Class D** |
| Management Fees | 0.64% |
| Other Expenses | 0.15% |
| Total Annual Fund Operating Expenses | 0.79% |

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**EXAMPLE:**

The Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated, reinvest all dividends and distributions, and then redeem all of your Shares at the end of each period. The Example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

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| | | | | |
|:---|:---|:---|:---|:---|
|  | **1 Year** | **3 Years** | **5 Years** | **10 Years** |
| Class D Shares | $81 | $252 | $439 | $978 |

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**Portfolio Turnover:** The Fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the Example, affect the Fund's performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 8% of the average value of its portfolio.

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**Principal investment strategies**<br>

The Fund pursues its investment objective by investing at least 50% of its equity assets in small- and medium-sized companies. The Fund may also invest in larger companies with strong growth potential. Small- and medium-sized companies are defined by the portfolio managers as those companies whose market capitalization falls within the range of companies in the Russell 2500<sup>tm</sup> Growth Index at the time of initial purchase. Market capitalization is a commonly used measure of the size and value of a company. The market capitalizations within the index will vary, but as of September 30, 2022, they ranged from approximately $4 million to $18.09 billion. The Fund may invest in shares of companies through initial public offerings and secondary offerings.

The portfolio managers apply a "bottom up" approach in choosing investments. In other words, the portfolio managers look at companies one at a time to determine if a company is an attractive investment opportunity and if it is consistent with the Fund's investment policies. Factors that the portfolio managers may consider in their fundamental analysis include a company's valuation, operating margins, or returns on capital. The portfolio managers will generally consider selling a position when, among other things, there is a deterioration in a company's competitive position or financials, a company reaches or exceeds its targeted value, or if a company's market capitalization exceeds the top of the small- and medium-sized range.

The Fund may also invest in foreign securities, which may include investments in emerging markets.

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The Fund may seek to earn additional income through lending its securities to certain qualified broker-dealers and institutions on a short-term or long-term basis, in an amount equal to up to one-third of its total assets as determined at the time of the loan origination.

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**Principal investment risks**<br>

The biggest risk is that the Fund's returns will vary, and you could lose money. The Fund is designed for long-term investors seeking an equity portfolio, including common stocks. Common stocks tend to be more volatile than many other investment choices. The principal risks associated with investing in the Fund are set forth below.

***Market Risk.*** The value of the Fund's portfolio may decrease due to short-term market movements and over more prolonged market downturns. As a result, the Fund's net asset value may fluctuate and it may be more difficult to value or sell the Fund's holdings. Market risk may affect a single issuer, industry, economic sector, or the market as a whole. Market risk may be magnified if certain social, political, economic, and other conditions and events (such as terrorism, conflicts, including related sanctions, social unrest, natural disasters, epidemics and pandemics, including COVID-19) adversely interrupt the global economy and financial markets. It is important to understand that the value of your investment may fall, sometimes sharply, in response to changes in the market, and you could lose money.

***Portfolio Management Risk.*** The Fund is an actively managed investment portfolio and is therefore subject to the risk that the investment strategies and research process employed for the Fund may fail to produce the intended results. The Fund may underperform its benchmark index or other mutual funds with similar investment objectives.

***Small- and Mid-Sized Companies Risk.*** Investments in securities issued by small- and mid-sized companies, which can include smaller, start-up companies offering emerging products or services, may involve greater risks than are customarily associated with larger, more established companies. For example, while small- and mid-sized companies may realize more substantial growth than larger or more established issuers, they may also suffer more significant losses as a result of their narrow product lines, limited operating history, greater exposure to competitive threats, limited financial resources, limited trading markets, and the potential lack of management depth. Securities issued by small- and mid-sized companies tend to be more volatile and somewhat more speculative than securities issued by larger or more established companies and may underperform as compared to the securities of larger or more established companies. These holdings are also subject to wider price fluctuations and tend to be less liquid than stocks of larger or more established companies, which could have a significant adverse effect on the Fund's returns, especially as market conditions change.

***Growth Securities Risk.*** Securities of companies perceived to be "growth" companies may be more volatile than other stocks and may involve special risks. If the portfolio managers' perception of a company's growth potential is not realized, the securities purchased may not perform as expected, reducing the Fund's returns. In addition, because different types of stocks tend to shift in and out of favor depending on market and economic conditions, "growth" stocks may perform differently from the market as a whole and other types of securities.

***Industry and Sector Risk.*** Although the Fund does not concentrate its investments in specific industries or sectors, it may have a significant portion of its assets invested in securities of companies conducting similar business, or business within the same economic sector. Companies in the same industry or economic sector may be similarly affected by economic or market events, making the Fund more vulnerable to unfavorable developments than funds that invest more broadly. As the Fund's portfolio becomes more concentrated, the Fund is less able to spread risk and potentially reduce the risk of loss and volatility. In addition, the Fund may be overweight or underweight in certain industries or sectors relative to its benchmark index, which may cause the Fund's performance to be more or less sensitive to developments affecting those sectors.

***Initial Public Offering and Secondary Offering Risk.*** Initial public offerings ("IPOs") and secondary offering shares frequently are volatile in price due to the absence of a prior public market, the small number of shares available for trading, and limited information about the issuer. Therefore, the Fund may hold IPO and secondary offering shares for a very short period of time. This may increase the portfolio turnover rate of the Fund and may lead to increased expenses for the Fund, such as commissions and transaction costs. Although IPOs and secondary offerings may have had a positive impact on the Fund's performance in the past, there can be no assurance that the Fund will identify favorable IPO and secondary offering investment opportunities in the future. In addition, as the Fund increases in size, the impact of IPOs and secondary offerings on the Fund's performance will generally decrease.

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***Foreign Exposure Risk.*** Foreign markets, including emerging markets, can be more volatile than the U.S. market. As a result, the Fund's returns and net asset value may be affected by fluctuations in currency exchange rates or political or economic conditions in a particular country. In some foreign markets, there may not be protection against failure by other parties to complete transactions. It may not be possible for the Fund to repatriate capital, dividends, interest, and other income from a particular country or governmental entity. In addition, a market swing in one or more countries or regions where the Fund has invested a significant amount of its assets may have a greater effect on the Fund's performance than it would in a more geographically diversified portfolio. The Fund's investments in emerging market countries, if any, may involve risks greater than, or in addition to, the risks of investing in more developed countries.

***Securities Lending Risk.*** There is the risk that when portfolio securities are lent, the securities may not be returned on a timely basis, and the Fund may experience delays and costs in recovering the security or gaining access to the collateral provided to the Fund to collateralize the loan. If the Fund is unable to recover a security on loan, the Fund may use the collateral to purchase replacement securities in the market. There is a risk that the value of the collateral could decrease below the cost of the replacement security by the time the replacement investment is made, resulting in a loss to the Fund.

*An investment in the Fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.*

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**Performance information**<br>

The following information provides some indication of the risks of investing in the Fund by showing how the Fund's performance has varied over time. Class D Shares of the Fund commenced operations on February 16, 2010, as a result of the restructuring of Class J Shares, the predecessor share class. The performance shown for Class D Shares for periods prior to February 16, 2010, reflects the performance of the Fund's former Class J Shares, calculated using the fees and expenses in effect during the periods shown, net of any applicable fee and expense limitations or waivers. If Class D Shares of the Fund had been available during periods prior to February 16, 2010, the performance shown may have been different. The performance shown for the periods following the Fund's commencement of Class D Shares reflects the fees and expenses of Class D Shares, net of any applicable fee and expense limitations or waivers.

The bar chart depicts the change in performance from year to year during the periods indicated. The table compares the Fund's average annual returns for the periods indicated to a broad-based securities market index, as well as to one or more supplemental indices that have investment characteristics similar to those of the Fund. All figures assume reinvestment of dividends and distributions. For certain periods, the Fund's performance reflects the effect of expense waivers. Without the effect of these expense waivers, the performance shown would have been lower.

*The Fund's past performance (before and after taxes) does not necessarily indicate how it will perform in the future. Updated performance information is available at janushenderson.com/allfunds or by calling 1-800-525-3713.* 

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|:---|
| **Annual Total Returns for Class D Shares** (calendar year-end) |
| &nbsp;&nbsp; ![](g753654img8500f6f81.jpg)<br>|

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| | | | | | |
|:---|:---|:---|:---|:---|:---|
| **Best Quarter:** | 2nd Quarter 2020 | **29.44%** | **Worst Quarter:** | 1st Quarter 2020 | **– 27.82%** |

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| | | | | |
|:---|:---|:---|:---|:---|
| **Average Annual Total Returns** (periods ended 12/31/22) |  |  |  |  |
|  | **1 Year** | **5 Years** | **10 Years** | &nbsp;&nbsp; **Since** <br> **Inception**<br> **(2/25/05)**<br>|
| **Class D Shares** |  |  |  |  |
| Return Before Taxes | – 23.68% | 5.04% | 10.52% | 10.87% |
| Return After Taxes on Distributions | – 24.76% | 3.00% | &nbsp;&nbsp; 8.69% | &nbsp;&nbsp; 9.48% |
| Return After Taxes on Distributions and Sale of Fund Shares<sup>(1)</sup> <br>| – 13.26% | 3.94% | &nbsp;&nbsp; 8.46% | &nbsp;&nbsp; 9.09% |
| &nbsp;&nbsp;&nbsp;&nbsp; Russell 2500<sup>TM</sup> Growth Index<br> (reflects no deduction for expenses, fees, or taxes)<br>| – 26.21% | 5.97% | 10.62% | &nbsp;&nbsp; 8.80% |
| &nbsp;&nbsp;&nbsp;&nbsp; Russell 2000<sup>®</sup> Growth Index<br> (reflects no deduction for expenses, fees, or taxes)<br>| – 26.36% | 3.51% | &nbsp;&nbsp; 9.20% | &nbsp;&nbsp; 7.63% |

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(1) If the Fund incurs a loss, which generates a tax benefit, the Return After Taxes on Distributions and Sale of Fund Shares may exceed the Fund's other return figures.

The Fund's primary benchmark index is the Russell 2500 Growth Index. The Fund also compares its performance to the Russell 2000 Growth Index. The indices are described below.

• The Russell 2500 Growth Index measures the performance of those Russell 2500 companies with higher price-to-book ratios and higher forecasted growth values.

• The Russell 2000 Growth Index measures the performance of those Russell 2000 companies with higher price-to-book ratios and higher forecasted growth values.

After-tax returns are calculated using distributions for the Fund's Class D Shares for the periods following February 16, 2010; and for the Fund's Class J Shares, the predecessor share class, for periods prior to February 16, 2010. If Class D Shares of the Fund had been available during these earlier periods, distributions may have been different and thus, after-tax returns may have been different from those shown. After-tax returns are calculated using the historically highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on your individual tax situation and may differ from those shown in the preceding table. The after-tax return information shown above does not apply to Fund shares held through a tax-advantaged account, such as a 401(k) plan or an IRA.

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**Management**<br>

**Investment Adviser:** Janus Henderson Investors US LLC

**Portfolio Managers: Jonathan D. Coleman**, CFA, is Executive Vice President and Lead Portfolio Manager of the Fund, which he has managed or co-managed since May 2013. **Scott Stutzman**, CFA, is Executive Vice President and Co-Portfolio Manager of the Fund, which he has co-managed since July 2016.

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**Purchase and sale of Fund shares**<br>

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| | |
|:---|:---|
| **Minimum Investment Requirements** |  |
| To open a new regular Fund account | $2500 |
| To open a new regular Fund account with an automatic investment program of $50 per month | $100 |
| To open a new UGMA/UTMA account, Coverdell Education Savings Account, or a retirement Fund account |  |
| &nbsp;&nbsp;&nbsp;&nbsp; • without an automatic investment program | $1000 |
| &nbsp;&nbsp;&nbsp;&nbsp; • with an automatic investment program of $50 per month | $100 |
| To add to any existing type of Fund account without an automatic investment program | $50 |

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You may generally purchase, exchange, or redeem Fund Shares on any business day by written request, wire transfer, telephone, and in most cases, online at janushenderson.com/individual. You may conduct transactions by mail (Janus Henderson, P.O. Box 219109, Kansas City, MO 64121-9109), or by telephone at 1-800-525-3713. Purchase, exchange, or redemption requests must be received in good order by the Fund or its agents prior to the close of the trading session of

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the New York Stock Exchange in order to receive that day's net asset value. For additional information, refer to "To Open an Account or Buy Shares," "To Exchange Shares," and/or "To Sell Shares" in the Prospectus.

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**Tax information**<br>

The Fund's distributions are taxable, and will be taxed as ordinary income or capital gains, unless you are investing through a tax-advantaged arrangement, such as a 401(k) plan or an individual retirement account (in which case you may be taxed upon withdrawal of your investment from such account).

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**Payments to broker-dealers and other financial intermediaries**<br>

With respect to share classes not offered in this Prospectus, the Fund or its distributor (or its affiliates) pay select broker-dealer firms or other financial intermediaries for the sale of Fund shares and related services. These payments may create a conflict of interest by influencing a broker-dealer or other intermediary or a salesperson to recommend the Fund over another investment or to recommend one share class over another.

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