[JANUS HENDERSON LOGO]
Janus Henderson Mid Cap Value Fund 
Ticker:
JDPAX
Class A Shares
JMVIX
Class S Shares
JDPNX
Class N Shares
JMCVX
Class T Shares
 
JMVCX
Class C Shares
JMVAX
Class I Shares
JDPRX
Class R Shares
 
 
Summary Prospectus dated October 28, 2026
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.
 
Investment Objective
Janus Henderson Mid Cap Value Fund seeks capital appreciation.
 
Fees and Expenses of the Fund
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 58 of the Fund’s Prospectus and in the “Purchases” section on page 72 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. 
SHAREHOLDER FEES
(fees paid directly from your investment)
 
Class A
 
Class C
 
Class S
 
Class I
 
Class N
 
Class R
 
Class T
Maximum Sales Charge (load) Imposed on Purchases (as a
percentage of offering price)
5.75%
None
None
None
None
None
None
Maximum Deferred Sales Charge (load) (as a percentage of
the lower of original purchase price or redemption
proceeds)
None
1.00%
None
None
None
None
None
  
ANNUAL FUND OPERATING EXPENSES
(expenses that you pay each year as a percentage of the value
of your investment)
 
Class A
 
Class C
 
Class S
 
Class I
 
Class N
 
Class R
 
Class T
Management Fees(1)
0.52%
0.52%
0.52%
0.52%
0.52%
0.52%
0.52%
Distribution/Service (12b-1) Fees
0.25%
1.00%
0.25%
None
None
0.50%
None
Other Expenses
0.15%
0.17%
0.28%
0.14%
0.03%
0.29%
0.28%
Total Annual Fund Operating Expenses
0.92%
1.69%
1.05%
0.66%
0.55%
1.31%
0.80%
 
(1)
This fee may adjust up or down monthly based on the Fund’s performance relative to its benchmark index over the performance measurement period. For more information regarding performance-based advisory fees, refer to “Management Expenses” in the Fund’s Prospectus.
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: 
If Shares are redeemed:
1 Year
3 Years
5 Years
10 Years
Class A Shares
$ 663
$ 851
$ 1,055
$ 1,641
Class C Shares
$ 272
$ 533
$ 918
$ 1,793
Class S Shares
$ 107
$ 334
$ 579
$ 1,283
Class I Shares
$ 67
$ 211
$ 368
$ 822
1 | Janus Henderson Mid Cap Value Fund
If Shares are redeemed:
1 Year
3 Years
5 Years
10 Years
Class N Shares
$ 56
$ 176
$ 307
$ 689
Class R Shares
$ 133
$ 415
$ 718
$ 1,579
Class T Shares
$ 82
$ 255
$ 444
$ 990
  
If Shares are not redeemed:
1 Year
3 Years
5 Years
10 Years
Class A Shares
$ 663
$ 851
$ 1,055
$ 1,641
Class C Shares
$ 172
$ 533
$ 918
$ 1,793
Class S Shares
$ 107
$ 334
$ 579
$ 1,283
Class I Shares
$ 67
$ 211
$ 368
$ 822
Class N Shares
$ 56
$ 176
$ 307
$ 689
Class R Shares
$ 133
$ 415
$ 718
$ 1,579
Class T Shares
$ 82
$ 255
$ 444
$ 990
 
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 31% of the average value of its portfolio.
 
Principal investment strategies
The Fund pursues its investment objective by investing, under normal circumstances, at least 80% of its net assets (plus any borrowings for investment purposes) in equity securities of mid-cap companies with value characteristics. For purposes of the Fund’s 80% investment policy, mid-cap companies are those whose market capitalization falls, at the time of purchase, within the 12-month capitalization range of the Russell Midcap® Value Index. The market capitalizations within the index will vary, but as of June 30, 2026, they ranged from approximately $480 million to $79.64 billion. For purposes of the Fund’s 80% investment policy, the Fund considers a company to have value characteristics if the company’s securities are (i) represented in appropriate third-party value-oriented indices or (ii) exhibit characteristics of a value company, considering historical or projected price to earnings ratios and projected sales relative to the equity market.
The Fund may also invest in foreign securities, as well as in real estate investment trusts (“REITs”) and similar REIT-like entities. From time to time, the Fund may invest in shares of companies through initial public offerings.
The Fund focuses on companies whose stock prices are believed to be undervalued by the Fund’s portfolio management or that have fallen out of favor with the market.
As defensive value managers, portfolio management generally looks for companies with:
•
strong management teams;
•
strong and stable balance sheets and solid recurring free cash flows;
•
attractive relative and absolute valuation ratios or that have underperformed recently;
•
favorable reward to risk characteristics;
•
sustainable competitive advantages that are trading at attractive valuations; and
•
strong long-term prospects.
Portfolio management’s philosophy is to weigh a security’s downside risk before considering its upside potential, which may help provide an element of capital preservation.
As part of its investment process, portfolio management considers environmental, social, and governance (“ESG”) risks and opportunities (“ESG Factors”) that it believes are financially material, alongside other fundamental investment factors. Examples of potential financially material ESG Factors include: corporate governance, company culture, exposure to climate change, and human capital management. To assess ESG Factors, portfolio management uses issuer reports, third-party data, and internally-generated analyses and may engage directly with issuers. ESG Factors are one of many considerations in the investment decision-making process, may not be determinative in deciding to include or exclude an investment from the portfolio, and may not be considered for every investment decision.
2 | Janus Investment Fund
 
Principal investment risks
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. 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 financial institution failures, economic recessions, tariffs, trade disputes, terrorism, war, armed conflicts, including related sanctions, social unrest, natural disasters, and epidemics and pandemics) 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.
Value Investing Risk. Because different types of stocks tend to shift in and out of favor depending on market and economic conditions, “value” stocks may perform differently than other types of stocks and from the market as a whole, and can continue to be undervalued by the market for long periods of time. It is also possible that a value stock will never appreciate to the extent expected.
Mid-Sized Companies Risk. Investments in securities issued by mid-sized companies may involve greater risks than are customarily associated with larger, more established companies. Securities issued by mid-sized companies tend to be more volatile 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.
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. Accordingly, the Fund may underperform benchmark indices or other funds with similar investment objectives.
Equity Securities Risk. Equity securities are subject to changes in value, and their values may be more volatile than those of other asset classes. The value of the Fund’s portfolio may decrease if the value of an individual company or security, or multiple companies or securities, in the portfolio decreases. Further, regardless of how well individual companies or securities perform, the value of the Fund’s portfolio could also decrease if there are deteriorating economic or market conditions or perceptions regarding the industries in which the issuers of securities the Fund holds participate.
REIT Risk. REITs are subject to certain risks inherent in the direct ownership of real estate, including without limitation, a possible lack of mortgage funds and associated interest rate risks, overbuilding, property vacancies, increases in property taxes and operating expenses, changes in zoning laws, losses due to environmental damages and changes in neighborhood values and appeal to purchasers. In addition, a REIT could fail to qualify for tax-free pass-through of its income under the Internal Revenue Code of 1986, as amended, or fail to maintain its exemption from registration under the Investment Company Act of 1940, as amended, which could produce adverse economic consequences for the REIT and its investors, including the Fund. Dividends received by the Fund from a REIT generally will not constitute qualified dividend income.
Initial Public Offering Risk. The Fund’s purchase of shares issued in an initial public offering (“IPO”) exposes it to the risks associated with companies that have little operating history as public companies, as well as to the risks inherent in those sectors of the market where these new issuers operate. There can be no assurance that the Fund will identify favorable IPO investment opportunities.
Foreign Exposure Risk. Foreign 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. Investments in foreign securities, particularly those of issuers located in emerging market countries, tend to have greater exposure to liquidity risk than domestic securities. 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.
3 | Janus Henderson Mid Cap Value Fund
ESG Integration Risk. There is a risk that considering ESG Factors as part of the Fund’s investment process may fail to produce the intended results or that the Fund may perform differently from funds that have a similar investment style but do not formally incorporate such considerations in their strategy. Information related to ESG Factors provided by issuers and third parties, which portfolio management may utilize, continues to develop and may be incomplete or inaccurate, use different or inconsistent methodologies, or be applied differently across issuers and industries.
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.
 
Performance information
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.
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 additional 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. 
Annual Total Returns for Class T Shares (calendar year-end)
 
 
Best Quarter:
4th Quarter 2020
18.20%
Worst Quarter:
1st Quarter 2020
-29.37%
  
Class T Shares’ year-to-date return as of the calendar quarter ended
September 30, 2026
was
6.48%
.
 
4 | Janus Investment Fund
Average Annual Total Returns (periods ended 12/31/25)
 
 
 
 
1 Year
5 Years
10 Years
Class T Shares
Return Before Taxes
6.70%
8.75%
8.62%
Return After Taxes on Distributions
4.31%
6.46%
6.52%
Return After Taxes on Distributions and Sale of Fund Shares(1)
5.43%
6.63%
6.55%
Class A Shares – Return Before Taxes(2)
0.46%
7.30%
7.78%
Class C Shares – Return Before Taxes(3)
4.82%
7.85%
7.74%
Class S Shares – Return Before Taxes
6.38%
8.46%
8.34%
Class I Shares – Return Before Taxes
6.84%
8.89%
8.76%
Class N Shares – Return Before Taxes
6.94%
9.01%
8.88%
Class R Shares – Return Before Taxes
6.18%
8.20%
8.07%
Russell 3000® Index
(reflects no deduction for expenses, fees, or taxes)
17.15%
13.15%
14.29%
Russell Midcap® Value Index
(reflects no deduction for expenses, fees, or taxes)
11.05%
9.83%
9.78%
 
(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.
(2)
Calculated assuming maximum permitted sales loads.
(3)
The one year return is calculated to include the contingent deferred sales charge.
The Fund’s broad-based benchmark index is the Russell 3000 Index, due to regulatory requirements. The Fund’s additional benchmark index is the Russell Midcap Value Index, which has investment characteristics similar to those of the Fund. The indices are described below.
•
The Russell 3000 Index measures the performance of the largest 3,000 U.S. companies.
•
The Russell Midcap Value Index measures the performance of those Russell Midcap companies with lower price-to-book ratios and lower forecasted growth values.
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.
 
Management
Investment Adviser:  Janus Henderson Investors US LLC
Portfolio Management:  Jeff Chen, CFA, is Co-Portfolio Manager of the Fund, which he has co-managed since October 2026. Justin Tugman, CFA, is Executive Vice President and Co-Portfolio Manager of the Fund, which he has managed or co-managed since March 2015.
 
5 | Janus Henderson Mid Cap Value Fund
Purchase and sale of Fund shares
Minimum Investment Requirements 
Class A Shares, Class C Shares*, Class S Shares, Class I Shares†, Class R Shares, and Class T Shares
 
Non-retirement accounts
$2,500**
Certain tax-advantaged accounts or UTMA accounts
$500
Class N Shares
Retirement investors (investing through an adviser-assisted, employer-sponsored retirement plan)
None
Retail investors (investing through a financial intermediary omnibus account)
$2,500***
Institutional investors (investing directly with the Fund)
$1,000,000
 
†
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 $250,000 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.
***
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. You should contact your financial intermediary or refer to your 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.
 
Tax information
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).
 
Payments to broker-dealers and other financial intermediaries
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. Ask your salesperson or visit your financial intermediary’s website for more information.
6 | Janus Investment Fund

[JANUS HENDERSON LOGO]
Janus Henderson Mid Cap Value Fund 
Ticker:
JNMCX
Class D Shares
Summary Prospectus dated October 28, 2026
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.
 
Investment Objective
Janus Henderson Mid Cap Value Fund seeks capital appreciation.
 
Fees and Expenses of the Fund
This table describes the fees and expenses that you may pay if you buy, hold, and sell Shares of the Fund. 
ANNUAL FUND OPERATING EXPENSES
(expenses that you pay each year as a percentage of the value of your investment)
 
Class D
Management Fees(1)
0.52%
Other Expenses
0.16%
Total Annual Fund Operating Expenses
0.68%
 
(1)
This fee may adjust up or down monthly based on the Fund’s performance relative to its benchmark index over the performance measurement period. For more information regarding performance-based advisory fees, refer to “Management Expenses” in the Fund’s Prospectus.
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: 
 
1 Year
3 Years
5 Years
10 Years
Class D Shares
$ 69
$ 218
$ 379
$ 847
 
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 31% of the average value of its portfolio.
 
Principal investment strategies
The Fund pursues its investment objective by investing, under normal circumstances, at least 80% of its net assets (plus any borrowings for investment purposes) in equity securities of mid-cap companies with value characteristics. For purposes of the Fund’s 80% investment policy, mid-cap companies are those whose market capitalization falls, at the time of purchase, within the 12-month capitalization range of the Russell Midcap® Value Index. The market capitalizations within the index will vary, but as of June 30, 2026, they ranged from approximately $480 million to $79.64 billion. For purposes of the Fund’s 80% investment policy, the Fund considers a company to have value characteristics if the company’s securities are (i) represented in appropriate third-party value-oriented indices or (ii) exhibit characteristics of a value company, considering historical or projected price to earnings ratios and projected sales relative to the equity market.
The Fund may also invest in foreign securities, as well as in real estate investment trusts (“REITs”) and similar REIT-like entities. From time to time, the Fund may invest in shares of companies through initial public offerings.
The Fund focuses on companies whose stock prices are believed to be undervalued by the Fund’s portfolio management or that have fallen out of favor with the market.
1 | Janus Henderson Mid Cap Value Fund
As defensive value managers, portfolio management generally looks for companies with:
•
strong management teams;
•
strong and stable balance sheets and solid recurring free cash flows;
•
attractive relative and absolute valuation ratios or that have underperformed recently;
•
favorable reward to risk characteristics;
•
sustainable competitive advantages that are trading at attractive valuations; and
•
strong long-term prospects.
Portfolio management’s philosophy is to weigh a security’s downside risk before considering its upside potential, which may help provide an element of capital preservation.
As part of its investment process, portfolio management considers environmental, social, and governance (“ESG”) risks and opportunities (“ESG Factors”) that it believes are financially material, alongside other fundamental investment factors. Examples of potential financially material ESG Factors include: corporate governance, company culture, exposure to climate change, and human capital management. To assess ESG Factors, portfolio management uses issuer reports, third-party data, and internally-generated analyses and may engage directly with issuers. ESG Factors are one of many considerations in the investment decision-making process, may not be determinative in deciding to include or exclude an investment from the portfolio, and may not be considered for every investment decision.
 
Principal investment risks
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. 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 financial institution failures, economic recessions, tariffs, trade disputes, terrorism, war, armed conflicts, including related sanctions, social unrest, natural disasters, and epidemics and pandemics) 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.
Value Investing Risk. Because different types of stocks tend to shift in and out of favor depending on market and economic conditions, “value” stocks may perform differently than other types of stocks and from the market as a whole, and can continue to be undervalued by the market for long periods of time. It is also possible that a value stock will never appreciate to the extent expected.
Mid-Sized Companies Risk. Investments in securities issued by mid-sized companies may involve greater risks than are customarily associated with larger, more established companies. Securities issued by mid-sized companies tend to be more volatile 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.
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. Accordingly, the Fund may underperform benchmark indices or other funds with similar investment objectives.
Equity Securities Risk. Equity securities are subject to changes in value, and their values may be more volatile than those of other asset classes. The value of the Fund’s portfolio may decrease if the value of an individual company or security, or multiple companies or securities, in the portfolio decreases. Further, regardless of how well individual companies or securities perform, the value of the Fund’s portfolio could also decrease if there are deteriorating economic or market conditions or perceptions regarding the industries in which the issuers of securities the Fund holds participate.
2 | Janus Investment Fund
REIT Risk. REITs are subject to certain risks inherent in the direct ownership of real estate, including without limitation, a possible lack of mortgage funds and associated interest rate risks, overbuilding, property vacancies, increases in property taxes and operating expenses, changes in zoning laws, losses due to environmental damages and changes in neighborhood values and appeal to purchasers. In addition, a REIT could fail to qualify for tax-free pass-through of its income under the Internal Revenue Code of 1986, as amended, or fail to maintain its exemption from registration under the Investment Company Act of 1940, as amended, which could produce adverse economic consequences for the REIT and its investors, including the Fund. Dividends received by the Fund from a REIT generally will not constitute qualified dividend income.
Initial Public Offering Risk. The Fund’s purchase of shares issued in an initial public offering (“IPO”) exposes it to the risks associated with companies that have little operating history as public companies, as well as to the risks inherent in those sectors of the market where these new issuers operate. There can be no assurance that the Fund will identify favorable IPO investment opportunities.
Foreign Exposure Risk. Foreign 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. Investments in foreign securities, particularly those of issuers located in emerging market countries, tend to have greater exposure to liquidity risk than domestic securities. 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.
ESG Integration Risk. There is a risk that considering ESG Factors as part of the Fund’s investment process may fail to produce the intended results or that the Fund may perform differently from funds that have a similar investment style but do not formally incorporate such considerations in their strategy. Information related to ESG Factors provided by issuers and third parties, which portfolio management may utilize, continues to develop and may be incomplete or inaccurate, use different or inconsistent methodologies, or be applied differently across issuers and industries.
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.
 
Performance information
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.
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 additional 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. 
3 | Janus Henderson Mid Cap Value Fund
Annual Total Returns for Class D Shares (calendar year-end)
 
 
Best Quarter:
4th Quarter 2020
18.20%
Worst Quarter:
1st Quarter 2020
-29.28%
  
Class D Shares’ year-to-date return as of the calendar quarter ended
September 30, 2026
was
6.56%
.
 
Average Annual Total Returns (periods ended 12/31/25)
 
 
 
 
1 Year
5 Years
10 Years
Class D Shares
Return Before Taxes
6.77%
8.85%
8.72%
Return After Taxes on Distributions
4.31%
6.50%
6.58%
Return After Taxes on Distributions and Sale of Fund Shares(1)
5.49%
6.70%
6.63%
Russell 3000® Index
(reflects no deduction for expenses, fees, or taxes)
17.15%
13.15%
14.29%
Russell Midcap® Value Index
(reflects no deduction for expenses, fees, or taxes)
11.05%
9.83%
9.78%
 
(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 broad-based benchmark index is the Russell 3000 Index, due to regulatory requirements. The Fund’s additional benchmark index is the Russell Midcap Value Index, which has investment characteristics similar to those of the Fund. The indices are described below.
•
The Russell 3000 Index measures the performance of the largest 3,000 U.S. companies.
•
The Russell Midcap Value Index measures the performance of those Russell Midcap companies with lower price-to-book ratios and lower forecasted growth values.
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.
 
Management
Investment Adviser:  Janus Henderson Investors US LLC
Portfolio Management:  Jeff Chen, CFA, is Co-Portfolio Manager of the Fund, which he has co-managed since October 2026. Justin Tugman, CFA, is Executive Vice President and Co-Portfolio Manager of the Fund, which he has managed or co-managed since March 2015.
 
4 | Janus Investment Fund
Purchase and sale of Fund shares
 
Minimum Investment Requirements
To open a new regular Fund account
$2,500
To open a new regular Fund account with an automatic investment program of $50 per month
$100
To open a new UTMA account, Coverdell Education Savings Account, or a retirement Fund account
• without an automatic investment program
$1,000
• 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
 
You may generally purchase, exchange, or redeem Fund Shares on any business day by written request, 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 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.
 
Tax information
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).
 
Payments to broker-dealers and other financial intermediaries
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.
5 | Janus Henderson Mid Cap Value Fund