This proxy statement is furnished in connection with the solicitation by and on behalf of the Board of Trustees (the “Trustees” or the “Board”) of JNL Series Trust (the “Trust”), a Massachusetts business trust, of proxies to be voted at a Special Meeting (the “Meeting”) of shareholders (the “Shareholders”) of the JNL/Mellon MSCI KLD 400 Social Index Fund (the “Fund”), a series of the Trust, to be held on March 28, 2018,25, 2022, at 9:10:00 a.m. Eastern Time, in the offices of Jackson National Life Insurance Company (“Jackson National”), 1 Corporate Way, Lansing, Michigan 48951, and any adjournmentadjournments thereof, for the purposes set forth in the accompanying Notice of Special Meeting of Shareholders (the “Notice”).

Due to the COVID-19 pandemic, Shareholders who attend the Meeting will be required to practice social distancing and to abide by all state and local restrictions. Multiple conference rooms may be used, as applicable, depending on the number of attendees and a dial in number will be provided. Each room is subject to frequent cleanings.

The purpose of the Meeting is to consider and act upon the following proposalproposals with respect to the Funds noted belowFund and to transact such other business as may properly come before the Meeting or adjournments thereof:

The Notice, this proxy statement, and the accompanying voting instructions card were first mailed on or about February 22, 2018.

Additional information regarding the Trust can be found in the Trust’s most recent annual and semi-annual reportsreport to Shareholders.

The Amended and Restated By-Laws of JNL Seriesthe Trust, dated September 6, 2019 (the “By-Laws”), provide that, except as otherwise provided by law, the Amended and Restated Declaration of Trust dated June 1, 1994 and amended and restated on September 25, 2017 (the “By-Laws”“Declaration of Trust”) provide that, or the By-Laws, the holders of a majority of the shares issued and outstanding and entitled to vote at the Meeting, present in person, present by means of remote communication in a manner, if any, authorized by the Board in its sole discretion, or represented by proxy, shall constitute a quorum for the transaction of business at a Shareholders’ meeting, except where any provision of law or the Amended and Restated Declaration of Trust dated September 25, 2017 (the “Declaration of Trust”) permits or requires that holders of any series or class shall vote as a series or class, then a majority of the aggregate number of shares in that series or class that are entitled to vote shall be necessary to constitute a quorum for the transaction of business by that series or class at a Shareholders’ meeting.business. The presence of Jackson National and/or Jackson National Life Insurance Company of New York (“Jackson NY,” and together with Jackson National, the “Insurance Companies”), through the presence of an authorized representative, constitutes a quorum.

The By-Laws further provide that shares may be voted in person or by proxy. A proxy with respect to shares held in the name of two or more persons shall be valid if executed by any one of them unless at or prior to the exercise of the proxy the Trust receives a specific written notice to the contrary from any one of them. A proxy purporting to be executed by or on behalf of a Shareholder shall be deemed valid unless challenged at or prior to its exercise, and the burden of proving its invalidity shall rest on the challenger. At all meetings of Shareholders, unless inspectors of election have been appointed, all questions relating to the qualification of voters and the validity of proxies and the acceptance or rejection of votes shall be decided by the chairman of the meeting. Any person giving voting instructions may revoke them at any time prior to their exercise by submitting to the Secretary of the Trust a superseding voting instruction form or written notice of revocation. Voting instructions can be revoked until the Meeting date. Only the Contract Owner executing the voting instructions can revoke them. The Insurance Companies will vote the shares of eachthe Fund in accordance with all properly executed and unrevoked voting instructions. Unless otherwise specified in the proxy, the proxy shall apply to all shares of eachthe Fund owned by the Shareholder.

Generally, a simple majority of votes cast is sufficient to take or authorize action upon any matter which may be presented for a Shareholder vote, unless more than a simple majoritydifferent vote is required by law, the

Approval of Proposal 1 will require the affirmative vote of a majority of the votes cast by the holders of all of the Shares present or represented and voting on that Proposal.

Approval of Proposal 2 and Proposal 3 will require the affirmative vote of a majority of the outstanding voting securities of eachthe Fund, as that term is defined under the Investment Company Act of 1940, as amended, (the “1940 Act”), which is the lesser of (a) a vote of 67% or more of the Fund shares whose holders are present or represented by proxy at the meeting if the holders of more than 50% of all outstanding Fund shares are present in person or represented by proxy at the meeting, or (b) a vote of more than 50% of all outstanding Fund shares.

If the Proposal isProposals are approved by Shareholders of each respectivethe Fund, itthey will be implemented on or about April 30, 2018.

The Trust is organized as a Massachusetts business trust. Interests in the Funds, eachFund, a series of the Trust, are represented by shares. Shares of eachthe Fund currently are sold only to separate accounts of Jackson National or Jackson NYthe Insurance Companies to fund the benefits of variable life insurance and variable annuity contracts (“Variable Contracts”) issued by JacksonNational or Jackson NY (the “issuing insurers”),the Insurance Companies, to employee benefit plans of Jackson National or directly to JacksonNational, Jackson NY,the Insurance Companies, or to regulated investment companies.certain funds of the Trust organized as funds-of-funds. Although the issuing insurersInsurance Companies legally own all of the shares of the FundsFund held in their respective separate accounts that relate to Variable Contracts, a portion of the value of your Variable Contract is invested by the relevant issuing insurer,Insurance Company, as provided in your Variable Contract, in shares of the Funds.

You have the right under your Variable Contractthe interpretations of the 1940 Act to instruct the issuing insurerInsurance Company how to vote the shares attributable to your Variable Contract. The issuing insurer will vote all such shares in accordance with the voting instructions timely given by the ownersOwners of Variable Contracts (“Contract(the “Contract Owners”) with assets invested in the Funds.  Contract Owners at the close of business on February 2, 2018January 31, 2022 (the “Record Date”), will be entitled to notice of the Meeting and to instruct the relevant issuing insurerInsurance Company how to vote at the Meeting or any adjourned session. JacksonNational and Jackson NYThe Insurance Company will vote all such shares owned by themselves orin accordance with the voting instructions timely given by the plansContract Owners with assets invested in the Fund. Shares for which an Insurance Company receives a voting instruction card that is signed, dated, and timely returned but is not marked to indicate voting instructions will be treated as an instruction to vote the Shares in favor of a Proposal. Shares for which an Insurance Company receives no timely voting instructions from a Contract Owner will be voted by the applicable Insurance Company either for or against approval of the applicable Proposal, or as an abstention, in the same proportion as the Shares for which Contract Owners have provided voting instructions to the Insurance Company. The Insurance Companies and their affiliates will vote their own shares and shares held by other regulated investment companies in the same proportion as voting instructions timely given by Contract Owners.

Contract Owners may use the enclosed voting instructions form as a ballot to give their voting instructions for those shares attributable to their Variable Contracts as of the Record Date. When a Contract Owner completes the voting instructions form and sends it to the appropriate issuing insurer, that issuing insurer will vote the shares attributable to the Variable Contract of the Contract Owner in accordance with the Contract Owner’s instructions. If a Contract Owner merely signs and returns the form, the issuing insurer will vote those shares in favor of the Proposal. If the Contract Owner does not return the form, the issuing insurer will vote those shares in the same proportion as shares for which instructions were received from other Contract Owners.  As a result of proportionate voting, a small number of Contract Owners could determine the outcome of the Proposal. The issuing insurersInsurance Companies have fixed the close of business on March 26, 2018,24, 2022, as the last day on which voting instructions will be accepted.

Any authorized voting instructions will be valid for any adjournment of the Meeting. If the Trust receives an insufficient number of votes to approve thea Proposal, the Meeting may be adjourned to permit the solicitation of additional votes. Those persons named as proxies in the voting instructions have the discretion to vote for any such adjournment.

AtAny person giving voting instructions may revoke them at any time prior to the Meeting any person giving voting instructions may revoke their voting instructions by providingsubmitting to the Secretary of the Trust Insurance Companies a properly executed written revocation of such voting instructions and properly executing later-dated voting instructions by asuperseding voting instruction card, telephoneform or the Internet,written notice of revocation or by appearing and voting in person at the Meeting. Only the Contract Owner executing the voting instructions can revoke them. The issuing insurersInsurance Companies will vote the shares of the Funds Fund in accordance with all properly executed and unrevokedun-revoked voting instructions.

record .

Contract Owners may be deemed to have an indirect beneficial interest in the Fund shares owned by the separate accounts. As noted above, Contract Owners have the right to give instructions to the Jackson National and Jackson NYinsurance company Shareholders as to how to vote the Fund shares attributable to their Variable Contracts. As of February 2, 2018,  the followingJanuary 31, 2022, no persons may be deemed to have an indirect beneficial interest totaling more than 25% of the voting securities of the Funds :Fund.

9 

JNL/Mellon Capital Industrials Sector Fund (Class I)
	Contract Owner's Name/Address	Percent Ownership of Shares of each Fund
	WFCS LLC FBO David Raymond One North Jefferson Avenue MAC H0006 St. Louis, MO 63103	45.27%
JNL/Mellon Capital Materials Sector Fund (Class I)
	Contract Owner's Name/Address	Percent Ownership of Shares of each Fund
	Kenneth Lange 9684 Ridge Top Trail Clarkston, MI 48348	67.56%

CONTINGENCY PLAN

If the Proposal isProposals are not approved by Shareholders, the Board will consider what actions are appropriate and in the best interests of Shareholders of the Funds.Fund. While the Board has made no determination regarding this contingency, it is possible that the Board would determine to re-solicit Shareholders of the FundsFund to approve the Proposal.

Proposals.

OTHER BUSINESS

The Trustees do not intend to present and do not have reason to believe that others will present any other items of business at the Meeting. However, if other matters are properly presented to the Meeting for a vote, the proxies will be voted upon such matters in accordance with the judgment of the persons acting under the proxies.

6

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The Trust does not hold regular meetings of Shareholders. Shareholders wishing to submit proposals for inclusion in a proxy statement for a subsequent meeting of Shareholders should send their written proposals to the Secretary of the Trust at the address set forth on the first page of this proxy statement.

Proposals must be received a reasonable time prior to the date of a meeting of Shareholders to be considered for inclusion in the proxy materials for a meeting. Timely submission of a proposal does not, however, necessarily mean that the proposal will be included. Persons named as proxies for any subsequent meeting of Shareholders will vote in their discretion with respect to proposals submitted on an untimely basis.

SOLICITATION OF PROXIES AND CONTRACT OWNER VOTING INSTRUCTIONS

In addition to the mailing of these proxy materials, voting instructions may be solicited by letter, telephone or personal contact by officers or employees of the Trust, JNAM or Jackson National.

officers or employees of the Insurance Companies.

JNAM, as the Trust’s Administrator,administrator, has retained the services of BroadridgeDonnelley Financial Solutions, Inc.LLC (“DFS”), 35 West Wacker Drive, Chicago, Illinois 60601. Under the agreement between JNAM and DFS, DFS’s subcontractor, Mediant Communications (“Mediant”), 400 Regency Parkway, Suite 200, Cordwainer Dr., Ste. 201, Norwell, Massachusetts 02061, to assist in the mailing ofCary, North Carolina 27519 will provide proxy statementsdistribution, solicitation, and solicitation of voting instructions.tabulation services (the “Services”). The anticipated cost of the servicesServices to be provided by Broadridge Financial Solutions, Inc.Mediant in connection with this proxy solicitation is approximately $9,272.

$7,478.

The costs of the printing and mailing of the Notice, this proxy statement,Proxy Statement, and the accompanying voting instruction card, and the solicitation of Contract Owner voting instructions, will be paid by JNAM. The Trust is not expected to bear any significant expenses in connection with the Meeting or the solicitation of proxies and voting instructions.

PROMPT EXECUTION AND RETURN OF THE ENCLOSED VOTING INSTRUCTIONS FORM IS REQUESTED. A SELF-ADDRESSED, POSTAGE-PAID ENVELOPE IS ENCLOSED FOR YOUR CONVENIENCE.

	/s/ Mark D. Nerud
	Mark D. Nerud
	Trustee, President, and Chief Executive Officer
	Dated: February 9, 2018	2022
	Lansing, Michigan

Appendix A

Summary Prospectus – April 25, 2022April 26, 2021

JNL/Morningstar U.S. Sustainability Index Fund

(formerly, JNL/Mellon MSCI KLD 400 Social Index Fund)

Class A

Class I

7

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Investment Objective. The investment objective of the Fund is to seek to track the performance of the Morningstar^® US Sustainability Index℠MSCI KLD 400 Social Index, which is designed to provide broad US equity market exposure with loweran index composed of U.S. companies that have positive environmental, social and governance (“ESG”) riskcharacteristics as identified by the index provider.

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

The expenses do not reflect the expenses of the variable insurance contracts or the separate account through which you indirectly invest in the Fund, whichever may be applicable, and the total expenses would be higher if they were included.

You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.

Shareholder Fees
(fees paid directly from your investment)
Not Applicable

Expense Example. This example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. Also, this example does not reflect the expenses of the variable insurance contracts or the separate account through which you indirectly invest in the Fund, whichever may be applicable, and the total expenses would be higher if they were included. The table below shows the expenses you would pay on a $10,000 investment, assuming (1) 5% annual return; (2) redemption at the end of each time period; and (3) that the Fund operating expenses remain the same. The example also assumes that the Class I administrative fee waiver is discontinued after one year. Although your actual costs may be higher or lower, based on these assumptions, your costs would be:

Portfolio Turnover (% of average value of portfolio). 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. These costs, which are not reflected in Annual Fund Operating Expenses or in the Expense Example above, affect the Fund’s performance.

Principal Investment Strategies. The Fund, under normal circumstances, seeks to invest at least 80% of its assets (net assets plus the amount of any borrowings made for investment purposes) in securities included in the Morningstar^® US Sustainability Index℠ (the “Index”), including depositary receipts representing securities of the Index. The Fund seeks to track the investment results of the Index, which is designed to provide broad U.S. equity market exposure with lower ESG risk. The Index includes large- and mid-capitalization companies and employs a best-in-class stock selection process to reduce exposure to companies with high ESG risk relative to their sector peers, targeting coverage of 50% of the Morningstar^® US Large-Mid Cap Index (the “parent index”) by float-adjusted market capitalization. Sector constraints are applied to preserve market-like exposure. The Fund’s investments may be concentrated in certain industries to the extent such industries are represented in the Index.

As of December 31 , 2021, the Index consisted of 374 constituents identified by Morningstar Indexes (the “Index Provider”) and the full market capitalization range was $ 298 million to $ 2,142,191 million. The number of constituents in the Index is subject to the selection and eligibility criteria at the time of reconstitution. The Index is reconstituted semi-annually and implemented after the close of business on the third Friday of June and December and is effective the following Monday. The Index is rebalanced quarterly and implemented after the close of business on the third Friday of March, June, September, and December and is effective the following Monday. If Monday is a holiday, reconstitution or rebalancing is effective on the following business day.

The Index Provider defines sustainable investing as an approach that takes into account ESG factors and their impact throughout the investment process.

All constituents within the Index must meet the following criteria in sequence: (i) the security must have a current Sustainalytics ESG Risk Rating and Sustainalytics Controversy Score, (ii) the security’s Controversy Score must be 3 out of 5, or lower, (iii) the security must not have a ‘Severe’ Sustainalytics ESG Risk Rating, and (iv) the company must not derive more than 50% of its revenue from tobacco products, not have any involvement in the production of controversial weapons (land mines, for example) as defined by third-party Sustainalytics Global Compact Compliance Service exclusionary lists, not have any involvement in the manufacturing and sale of firearms to civilian customers, and not have any involvement in the manufacturing and sale of key components of small arms. The Index Provider selects the best-in-class companies in priority order of their Sustainalytics ESG Risk Ratings until they reach 50% coverage by float-adjusted market capitalization of the parent index. The companies with the lowest possible ESG Risk Ratings are selected for the Index, subject to sector weight constraints relative to the parent index.

Sustainalytics’ ESG Risk Ratings are designed to help investors identify and understand financially material ESG risks in their portfolio companies. Sustainalytics’ ESG Risk Ratings measure the degree to which a company’s economic value is driven by the magnitude of a company’s unmanaged ESG risks. Sustainalytics’ ESG Risk Ratings are composed of three building blocks that contribute to a company’s overall rating. These building blocks include Corporate Governance, material ESG issues (“MEIs”), and idiosyncratic ESG issues.  To be considered relevant in the ESG Risk Ratings, an issue must have a potentially substantial impact on the economic value of a company and, hence, its financial risk- and return profile from an investment perspective. The ESG Risk Rating is forward looking in the sense that it identifies these issues based on the typical business model and business environment a company is operating in. The final ESG Risk Rating score is calculated as the sum of all unmanaged risk. To determine unmanaged risk, Sustainalytics reviews three building blocks: Corporate Governance, MEIs’, and idiosyncratic ESG issues. Based on their quantitative scores, companies are grouped into one of five risk categories (negligible, low, medium, high, severe) per the chart below. A low score indicates a low level of ESG risk.

Mellon Investments Corporation, the Fund’s sub-adviser (“Sub-Adviser”), does not apply its own ESG screening criteria. The Sub-Adviser relies on the Index Provider to apply its screening criteria to portfolio companies included in the Index.

The Fund employs a passive investment approach, called indexing, which attempts to replicate the investment performance of the Index through full replication or representative sampling. The Fund does not employ traditional methods of active investment management,

which involves the buying and selling of securities based upon fundamental security analysis. The Fund attempts to replicate the Index by investing all or substantially all of its assets in the stocks that make up the Index.

When attempting to replicate an index such as the Index, portfolio turnover is generally reduced to security additions or deletions to the index, contract owner contributions and withdrawals, and reinvestment income. The Fund stays aligned with the benchmark automatically with the change in share price, due to the close similarity between the holdings of the Index and those of the Fund such that the replicated portfolio does not require rebalancing as a result of market movement. The Fund is managed and rebalanced to reflect the composition of the Index.

The Fund may also invest in a combination of exchange-traded funds (“ETFs”) and cash to maintain correlation to the Index to assist with the Index rebalances and to meet redemption or purchase requests.

The Fund may invest in financial futures, a type of exchange-traded derivative that may be used to obtain exposure to a variety of underlying assets, to provide liquidity for cash flows, to hedge dividend accruals or for other purposes that facilitate meeting the Fund’s objective. The Fund’s use of financial futures is intended to assist replicating the investment performance of the Index.

The Fund is a “non-diversified” fund, as defined in the Investment Company Act of 1940, as amended (the “1940 Act”), and may invest more of its assets in fewer issuers than “diversified” mutual funds.

The Fund seeks to track the investment results of the MSCI KLD 400 Social Index (the “Index”), which is a free float-adjusted market capitalization index designed to target U.S. companies that have positive environmental, social and governance (“ESG”) characteristics. As of December 31, 2020, the Index consisted of 403 companies identified by MSCI Inc. (the “Index Provider” or “MSCI”) from the universe of companies included in the MSCI USA IMI Index, which targets 99% of the market coverage of stocks that are listed for trading on the New York Stock Exchange (“NYSE”), NASDAQ Stock Market and the NYSE MKT LLC. MSCI analyzes each eligible company’s ESG performance using proprietary ratings covering ESG criteria. The ratings identify the following six to ten issues: climate change, natural resources, pollution and waste, environmental opportunities, human capital, product liability, stakeholder opposition, social opportunities, corporate governance, and corporate behavior. The ESG criteria includes, but is not limited to, a company’s level of exposure relating to a material issue and the company’s management process of that issue. To assess a company’s exposure to and management of ESG risks and opportunities, the MSCI collects data from at a segment or geographic level from academic, government datasets; publicly filed company reports; government databases; media; and similar sources. Companies that MSCI determines have significant involvement in the following businesses are not eligible for the Index: alcohol, tobacco, gambling, civilian firearms, nuclear power, military weapons, adult entertainment and genetically modified organisms. The Index may include large-, mid- or small capitalization companies. Components of the Index primarily include consumer discretionary, healthcare and information technology companies. The components of the Index, and the degree to which these components represent certain industries, are likely to change over time.

Mellon Investments Corporation (“Sub-Adviser”) uses a “passive” or indexing approach to try to achieve the Fund’s investment objective. Unlike many investment companies, the Fund does not try to “beat” the index it tracks and does not seek temporary defensive positions when markets decline or appear overvalued.

The Fund does not employ traditional methods of active investment management, such as actively buying and selling bonds based upon interest rate bets or sector rotation. Indexing may offer a cost-effective approach to gaining diversified market exposure over the long-term.

The Fund generally invests at least 90% of its assets in securities of the Index and in depositary receipts representing securities of the Index. The Fund may invest the remainder of its assets in certain futures, options and swap contracts, cash and cash equivalents, including shares of money market funds advised by the Sub-Adviser or its affiliates, as well as in securities not included in the Index, but which the Sub-Adviser believes will help the Fund track the Index. The Fund seeks to track the investment results of the Index before fees and expenses of the Fund.

The Fund may invest in financial futures, a type of derivative that may be used to obtain exposure to a variety of underlying assets, to provide liquidity for cash flows, to hedge dividend accruals or for other purposes that facilitate meeting the Fund’s objective. The Fund’s use of financial futures is intended to assist replicating the investment performance of the Index.

The Fund may invest in exchange-traded funds (“ETFs”) to assist with fund rebalances and to meet redemption or purchase requests. The Fund’s holdings are rebalanced on a regular basis to reflect changes in the composition of the Index.

The Fund seeks to track the investment results of the Index, which is a free float-adjusted market capitalization index designed to target U.S. companies that have ESG characteristics. The Fund’s investments may be concentrated in certain industries to the extent such industries are represented in the Index.

Principal Risks of Investing in the Fund. An investment in the Fund is not guaranteed. As with any mutual fund, the value of the Fund’s shares will change, and you could lose money by investing in the Fund. The principal risks associated with investing in the Fund include:

market restrictions, or other legal reasons, including regulatory limits or other restrictions on securities that may be purchased by the Investment Adviser and its affiliates.

Performance. The performance information shown provides some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual returns compared with those of a broad-based securities market index which has investment characteristics similar to those of the Fund. The Fund’s past performance is not necessarily an indication of how the Fund will perform in the future.

The returns shown in the bar chart and table do not include charges that will be imposed by variable insurance products. If these amounts were reflected, returns would be less than those shown.

Effective April 25, 2022, for consistency with the Fund’s principal investment strategies, the Fund will replace the MSCI KLD 400 Social Index with the Morningstar^® US Sustainability Index^SM as the Fund’s primary benchmark.

For consistency with the Fund’s principal investment strategies, the Fund added the Morningstar^® US Large-Mid Cap Index^SM as the Fund’s secondary benchmark.

Annual Total Returns as of December 31

Class A

Best Quarter (ended 6/30/2020): 21.40%; Worst Quarter (ended 3/31/2020): -18.35%

Annual Total Returns as of December 31

Class I

Best Quarter (ended 6/30/2020): 21.54%; Worst Quarter (ended 3/31/2020): -18.25%

Portfolio Management.

Investment Adviser to the Fund:
Jackson National Asset Management, LLC (“JNAM”)

Sub-Adviser:
Mellon Investments Corporation (“Mellon”)

Portfolio Managers:

Purchase and Redemption of Fund Shares

Only separate accounts of Jackson National Life Insurance Company (“Jackson”) or Jackson National Life Insurance Company of New York (“Jackson NY”) and series, including fund of funds, of registered investment companies in which either or both of those insurance companies invest may purchase shares of the Fund. You may invest indirectly in the Fund through your purchase of a variable annuity or life insurance contract issued by a separate account of Jackson or Jackson NY that invests directly, or through a fund of funds, in this Fund. Any minimum initial or subsequent investment requirements and redemption procedures are governed by the applicable separate account through which you invest indirectly.

This Fund serves as an underlying investment by insurance companies, affiliated investment companies, and retirement plans for funding variable annuity and life insurance contracts and retirement plans.

Tax Information

The Fund expects to be treated as a partnership for U.S. federal income tax purposes, and does not expect to make regular distributions (other than in redemption of Fund shares) to shareholders, which generally are the participating insurance companies investing in the Fund through separate accounts of Jackson or Jackson NY and mutual funds owned directly or indirectly by such separate accounts. You should consult the prospectus of the appropriate separate account or description of the plan for a discussion of the U.S. federal income tax consequences to you of your contract, policy, or plan.

Payments to Broker-Dealers and Financial Intermediaries

If you invest in the Fund under a variable insurance contract or a plan that offers a variable insurance contract as a plan option through a broker-dealer or other financial intermediary (such as a financial institution), the Fund and its related companies 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. Ask your salesperson or visit your financial intermediary’s Website for more information.

JNL/Mellon MSCI KLD 400 Social Index Fund

Class A

Class I

Investment Objective. The investment objective of the Fund is to seek to track the performance of the Morningstar^® US Sustainability Index℠MSCI KLD 400 Social Index, which is designed to provide broad US equity market exposure with loweran index composed of U.S. companies that have positive environmental, social and governance (“ESG”) riskcharacteristics as identified by the index provider.

Principal Investment Strategies.The Fund, under normal circumstances, seeks to invest at least 80% of its assets (net assets plus the amount of any borrowings made for investment purposes) in securities included in the Morningstar^® US Sustainability Index℠ (the “Index”), including depositary receipts representing securities of the Index. The Fund seeks to track the investment results of the Index, which is designed to provide diversified, broad U.S. equity market exposure with lower ESG risk. The Index includes large- and mid-capitalization companies and employs a best-in-class stock selection process to reduce exposure to companies with high ESG risk relative to their sector peers, targeting coverage of 50% of the Morningstar^® US Large-Mid Cap Index (the “parent index”) by float-adjusted market capitalization. Sector constraints are applied to preserve market-like exposure. The Fund’s investments may be concentrated in certain industries to the extent such industries are represented in the Index.

As of December 31 , 2021, the Index consisted of 374 constituents identified by Morningstar Indexes (the “Index Provider”) and the full market capitalization range was $ 298 million to $ 2,142,191 million. The number of constituents in the Index is subject to the selection and eligibility criteria at the time of reconstitution. The Index is reconstituted semi-annually and implemented after the close of business on the third Friday of June and December and is effective the following Monday. The Index is rebalanced quarterly and implemented after the close of business on the third Friday of March, June, September, and December and is effective the following Monday. If Monday is a holiday, reconstitution or rebalancing is effective on the following business day.

The Index Provider defines sustainable investing as an approach that takes into account ESG factors and their impact throughout the investment process.

All constituents within the Index must meet the following criteria in sequence: (i) the security must have a current Sustainalytics ESG Risk Rating and Sustainalytics Controversy Score, (ii) the security’s Controversy Score must be 3 out of 5, or lower, (iii) the security must not have a ‘Severe’ Sustainalytics ESG Risk Rating, and (iv) the company must not derive more than 50% of its revenue from tobacco products, not have any involvement in the production of controversial weapons (land mines, for example) as defined by third-party Sustainalytics Global Compact Compliance Service exclusionary lists, not have any involvement in the manufacturing and sale of firearms to civilian customers, and not have any involvement in the manufacturing and sale of key components of small arms. The Index Provider selects the best-in-class companies in priority order of their Sustainalytics ESG Risk Ratings until they reach 50% coverage by float-adjusted market capitalization of the parent index. The companies with the lowest possible ESG Risk Ratings are selected for the Index, subject to sector weight constraints relative to the parent index.

Sustainalytics’ ESG Risk Ratings are designed to help investors identify and understand financially material ESG risks in their portfolio companies. Sustainalytics’ ESG Risk Ratings measure the degree to which a company’s economic value is driven by the magnitude of a company’s unmanaged ESG risks. Sustainalytics’ ESG Risk Ratings are composed of three building blocks that contribute to a company’s overall rating. These building blocks include Corporate Governance, material ESG issues (“MEIs”), and idiosyncratic ESG issues.  To be considered relevant in the ESG Risk Ratings, an issue must have a potentially substantial impact on the economic value of a company and, hence, its financial risk- and return profile from an investment perspective. The ESG Risk Rating is forward looking in the sense that it identifies these issues based on the typical business model and business environment a company is operating in. The final ESG Risk Rating score is calculated as the sum of all unmanaged risk. To determine unmanaged risk, Sustainalytics reviews three building blocks: Corporate Governance, MEIs’, and idiosyncratic ESG issues. Based on their quantitative scores, companies are grouped into one of five risk categories (negligible, low, medium, high, severe) per the chart below. A low score indicates a low level of ESG risk.

The Fund employs a passive investment approach, called indexing, which attempts to replicate the investment performance of the Index through full replication or representative sampling. The Fund does not employ traditional methods of active investment management, which involves the buying and selling of securities based upon fundamental security analysis. The Fund attempts to replicate the Index by investing all or substantially all of its assets in the stocks that make up the Index.

When attempting to replicate an index such as the Index, portfolio turnover is generally reduced to security additions or deletions to the index, contract owner contributions and withdrawals, and reinvestment income. The Fund stays aligned with the benchmark automatically with the change in share price, due to the close similarity between the holdings of the Index and those of the Fund such that the replicated portfolio does not require rebalancing as a result of market movement. The Fund is managed and rebalanced to reflect the composition of the Index.

Indexing may offer a cost-effective investment approach to gaining diversified market exposure over the long term.

The Fund may also invest in a combination of exchange-traded funds (“ETFs”) and cash to maintain correlation to the Index to assist with the Index rebalances and to meet redemption or purchase requests.

The Fund may invest in financial futures, a type of exchange-traded derivative that may be used to obtain exposure to a variety of underlying assets, to provide liquidity for cash flows, to hedge dividend accruals or for other purposes that facilitate meeting the Fund’s objective. The Fund’s use of financial futures is intended to assist replicating the investment performance of the Index.

The Fund is a “non-diversified” fund, as defined in the Investment Company Act of 1940, as amended (the “1940 Act”), and may invest more of its assets in fewer issuers than “diversified” mutual funds.

The Fund seeks to track the investment results of the MSCI KLD 400 Social Index (the “Index” or “MSCI”), which is a free float-adjusted market capitalization index designed to target U.S. companies that have positive environmental, social and governance (“ESG”)

characteristics. As of December 31, 2020, the Index consisted of 403 companies identified by MSCI Inc. (the “Index Provider” or “MSCI”) from the universe of companies included in the MSCI USA IMI Index, which targets 99% of the market coverage of stocks that are listed for trading on the New York Stock Exchange (“NYSE”), NASDAQ Stock Market and the NYSE MKT LLC. MSCI analyzes each eligible company’s ESG performance using proprietary ratings covering ESG criteria. The ratings identify the following six to ten issues: climate change, natural resources, pollution and waste, environmental opportunities, human capital, product liability, stakeholder opposition, social opportunities, corporate governance, and corporate behavior. The ESG criteria includes, but is not limited to, a company’s level of exposure relating to a material issue and the company’s management process of that issue. To assess a company’s exposure to and management of ESG risks and opportunities, the MSCI collects data from at a segment or geographic level from academic, government datasets; publicly filed company reports; government databases; media; and similar sources. Companies that MSCI determines have significant involvement in the following businesses are not eligible for the Index: alcohol, tobacco, gambling, civilian firearms, nuclear power, military weapons, adult entertainment and genetically modified organisms. The Index may include large-, mid- or small capitalization companies. Components of the Index primarily include consumer discretionary, healthcare and information technology companies. The components of the Index, and the degree to which these components represent certain industries, are likely to change over time.

Mellon Investments Corporation (“Sub-Adviser”) uses a “passive” or indexing approach to try to achieve the Fund’s investment objective. Unlike many investment companies, the Fund does not try to “beat” the index it tracks and does not seek temporary defensive positions when markets decline or appear overvalued.

The Fund generally invests at least 90% of its assets in securities of the Index and in depositary receipts representing securities of the Index. The Fund may invest the remainder of its assets in certain futures, options and swap contracts, cash and cash equivalents, including shares of money market funds advised by the Sub-Adviser or its affiliates, as well as in securities not included in the Index, but which the Sub-Adviser believes will help the Fund track the Index. The Fund seeks to track the investment results of the Index before fees and expenses of the Fund.

The Fund may lend securities representing up to one-third of the value of the Fund’s total assets (including the value of any collateral received).

The Fund may invest in financial futures, a type of derivative that may be used to obtain exposure to a variety of underlying assets, to provide liquidity for cash flows, to hedge dividend accruals or for other purposes that facilitate meeting the Fund’s objective.

The Index is sponsored by MSCI, which is independent of the Fund and the Sub-Adviser. The Index Provider determines the composition and relative weightings of the securities in the Index and publishes information regarding the market value of the Index.

The Fund seeks to track the investment results of the Index, which is a free float-adjusted market capitalization index designed to target U.S. companies that have ESG characteristics. The Fund’s investments may be concentrated in certain industries to the extent such industries are represented in the Index. The Fund’s holdings are rebalanced on a regular basis to reflect changes in the composition of the Index.

Principal Risks of Investing in the Fund. An investment in the Fund is not guaranteed. As with any mutual fund, the value of the Fund’s shares will change, and you could lose money by investing in the Fund. The following descriptions of the principal risks do not provide any assurance either of the Fund’s investment in any particular type of security, or assurance of the Fund’s success in its investment selections, techniques and risk assessments. As an indexed portfolio, the Fund may not achieve its investment objective for a variety of reasons, the inability to purchase certain securities in the index, including changes in the financial condition of issuers (due to such factors as management performance, reduced demand or overall market changes), fluctuations in the financial markets, declines in overall securities prices, or country specific factors that would prevent the Fund from achieving its investment objective. The principal risks of investing in the Fund include:

Please see the “Glossary of Risks” section, which is set forth before the “Management of the Trust” section, for a description of these risks. There may be other risks that are not listed in this Prospectus that could cause the value of your investment in the Fund to decline and that could prevent the Fund from achieving its stated investment objective. This Prospectus does not describe all of the risks of every technique, investment strategy or temporary defensive position that the Fund may use. For additional information regarding the risks of investing in the Fund, please refer to the SAI.

Additional Information About the Other Investment Strategies, Other Investments and Risks of the Fund (Other than Principal Strategies/Risks). There may be additional risks that may affect the Fund’s ability to achieve its stated investment objective. Those additional risks are:

Please see the “Glossary of Risks” section, which is set forth before the “Management of the Trust” section in this Prospectus, for a description of these risks.

In addition, the performance of the Fund depends on the Sub-Adviser’s abilities to effectively implement the investment strategies of the Fund.

The SAI has more information about the Fund’s authorized investments and strategies, as well as the risks and restrictions that may apply to it.

The Sub-Adviser and Portfolio Management. Mellon Investments Corporation (“Mellon”) is a corporation organized under the laws of the State of Delaware and is an indirect subsidiary of The Bank of New York Mellon Corporation (“BNY Mellon Corp.”). Mellon is headquartered at BNY Mellon Center, One Boston Place, Boston, Massachusetts 02108.

Mellon supervises and manages the investment portfolio of the Fund and directs the purchase and sale of the Fund’s investment securities. Mellon utilizes teams of investment professionals acting together to manage the assets of the Fund. The team meets regularly to review portfolio holdings and to discuss purchase and sale activity. The team adjusts holdings in the portfolio as they deem appropriate in the pursuit of the Fund’s investment objectives. The individual members of the team who are jointly and primarily responsible for the day-to-day management of the Fund’s portfolio are:

Marlene Walker Smith is Director, Head of Equity Index - Portfolio Management at Mellon. Ms. Walker Smith joined Mellon in 1995. She leads a team of portfolio managers covering domestic and international index portfolios, as well as corporate actions. Ms. Walker Smith has been working in the investment industry since 1990. She holds an MBA from the University of Pittsburgh and a BA from Washington & Jefferson College.

David France, CFA, is Vice President and Senior Portfolio Manager at Mellon. Mr. France joined Mellon in 2009. He has been working in the investment industry since 2009. Mr. France is responsible for managing domestic and international equity indexing portfolios. He earned an MS in finance from Loyola University Maryland and a BSBA in accounting from Duquesne University. Mr. France holds the CFA^® designation and is a member of CFA Institute and CFA Society Pittsburgh.

Todd Frysinger, CFA, is Vice President and Senior Portfolio Manager at Mellon. Mr. Frysinger joined Mellon in 2007. Mr. Frysinger is responsible for managing domestic and international equity indexing portfolios. He earned an MS in finance from Boston College and a BS in finance and management from Elizabethtown College. He holds the CFA^® designation and is a member of CFA Institute and CFA Society Pittsburgh.

Vlasta Sheremeta, CFA, is Vice President and Senior Portfolio Manager at Mellon. Ms. Sheremeta joined Mellon in 2011. She has been working in the investment industry since 2010. Ms. Sheremeta is responsible for managing domestic and international equity indexing portfolios. Ms. Sheremeta earned an MBA from Carnegie Mellon University and a BS in business administration from the University of Pittsburgh. She holds the CFA^® designation, and is a member of CFA Institute and CFA Society Pittsburgh.

Michael Stoll is Vice President and Senior Portfolio Manager at Mellon. Mr. Stoll joined Mellon in 2005. He has been working in the investment industry since 2004. Mr. Stoll is responsible for managing domestic and international equity indexing portfolios. Mr. Stoll earned a BS in civil engineering from the University of California at Irvine, and an MBA and an MS in engineering from the University of California at Berkeley.

Ms. Walker Smith, Mr. France, Mr. Frysinger, Ms. Sheremeta and Mr. Stoll review trades proposed by the portfolio managers, review and monitor accounts, and approve corporate action responses for all domestic and international equity indexing funds and each has the authority to approve transactions to the Fund.

The SAI provides additional information about a portfolio manager’s compensation, other accounts managed, and ownership of securities in the Fund(s).

A discussion regarding the Board of Trustees’ basis for approving the sub-advisory agreement is available in the Fund’s Annual Report for the period ended December 31, 20212020.