Strategy. The Portfolio seeks to track the investment results of the MSCI KLD 400 Social Index (the Underlying Index), which is a free float-adjusted market capitalization index designed to provide exposure to U.S. companies that have positive environmental, social and governance (ESG) characteristics. As of December 31, 2024, the Underlying Index consisted of 402 securities 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 and the NASDAQ Stock Market. MSCI analyzes each eligible companys ESG performance using proprietary ratings covering ESG criteria, as described in more detail below. When … Show more… The Portfolio seeks to track the investment results of the MSCI KLD 400 Social Index (the Underlying Index), which is a free float-adjusted market capitalization index designed to provide exposure to U.S. companies that have positive environmental, social and governance (ESG) characteristics. As of December 31, 2024, the Underlying Index consisted of 402 securities 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 and the NASDAQ Stock Market. MSCI analyzes each eligible companys ESG performance using proprietary ratings covering ESG criteria, as described in more detail below. When selecting companies for the Underlying Index, MSCI also considers market capitalization and liquidity. Companies that MSCI determines have significant involvement in the following businesses are not eligible for the Underlying Index: fossil fuel extraction, fossil fuel reserves ownership, thermal coal power, alcohol, tobacco, gambling, nuclear weapons, controversial weapons, conventional weapons, civilian firearms, nuclear power, adult entertainment and genetically modified organisms. The Underlying Index may include large-, mid- or small-capitalization companies. The components of the Underlying Index are likely to change over time. The Underlying Index uses company ratings and research provided by MSCI ESG Research to determine eligibility. The following description is as of the date of this Prospectus and is subject to change as determined from time to time by MSCI: ? The Underlying Index uses research to identify companies that have demonstrated an ability to manage their ESG risks and opportunities. MSCI identifies key ESG issues that hold the greatest potential risk or opportunity for each industry sector: Environment Social Governance Carbon Emissions Labor Management Corporate Governance (Board Diversity; Executive Pay; Ownership and Control; Accounting) Product Carbon Footprint Human Capital Development Business Ethics Financing Environmental Impact Health and Safety Tax Transparency Climate Change Vulnerability Supply Chain Labor Standards Water Stress Product Safety and Quality Biodiversity and Land Use Chemical Safety Raw Material Sourcing Consumer Financial Protection Toxic Emissions and Waste Privacy and Data Security Packaging Material and Waste Responsible Investment Electronic Waste Controversial Sourcing Opportunities in Clean Tech Community Relations Opportunities in Green Building Opportunities in Nutrition and Health Opportunities in Renewable Energy Access to Finance Access to Healthcare MSCI analysts calculate the size of a companys exposure to each key issue based on an analysis of a companys business, then take into account the extent to which a company has developed strategies and demonstrated a strong track record of performance in managing its specific level of risks or opportunities. Using a sector-specific key issue weighting model, companies are rated and ranked in comparison to their sector peers. The companies in each sector undergo an annual review and are updated on a rolling basis as well as in response to major events. ? The Underlying Index uses research to identify those companies that are involved in very serious controversies involving the ESG impact of their operations or products and services. The MSCI research covers five categories of impact: environment, customers, human rights and community, labor rights and supply chain, and governance. Companies are scored based on an evaluation framework designed to be consistent with international norms and principles such as those expressed in declarations of the United Nations and its agencies. Companies deemed to be involved in the most severe controversies related to the ESG impact of their operations or products and services are excluded from the Underlying Index. The selection universe for the Underlying Index is large-, mid- and small-capitalization companies in the MSCI USA IMI Index. The Underlying Index targets a minimum of 200 large- and mid-capitalization constituents. The composition of the Underlying Index is reviewed on a quarterly basis. At each quarterly review, constituents are deleted from the Underlying Index if they are deleted from the MSCI USA IMI Index, if they fail the exclusion screens, or if their ESG ratings or scores fall below minimum standards. Additions are made to the Underlying Index to restore the number of constituents to 400 companies. All eligible securities of each issuer are included in the Underlying Index, so the Underlying Index may have more than 400 securities. The Underlying Index is rebalanced at the regular reviews in May, August, November and February. The Sub-Adviser uses a passive or indexing approach to try to achieve the Portfolios investment objective. Unlike many investment companies, the Portfolio does not try to beat the index it seeks to track and does not seek temporary defensive positions when markets decline or appear overvalued. Generally, the Sub-Adviser uses a replication indexing strategy to manage the Portfolio, although in certain instances the Sub-Adviser may use a representative sampling indexing strategy to manage the Portfolio. Replication is an indexing strategy that involves holding each security in the Underlying Index in approximately the same weight that the security represents in the Underlying Index. Representative sampling is an indexing strategy that involves investing in a representative sample of securities that collectively has an investment profile similar to that of the Underlying Index. The securities selected are expected to have, in the aggregate, investment characteristics (based on factors such as market capitalization and industry weightings), fundamental characteristics (such as return variability and yield) and liquidity measures similar to those of the Underlying Index. The Portfolio may or may not hold all of the securities in the Underlying Index. The Portfolio generally invests at least 90% of its total assets in securities of the Underlying Index and in depositary receipts representing securities of the Underlying Index. The Portfolio may invest the remainder of its assets in certain futures, options and swap contracts, cash and cash equivalents, including shares of money market funds, including affiliated money market funds, as well as in securities not included in the Underlying Index, but which the Sub-Adviser believes will help the Portfolio track the Underlying Index. The Portfolio seeks to track the investment results of the Underlying Index before fees and expenses of the Portfolio. The Portfolio may become non-diversified, as defined in the Investment Company Act of 1940, as amended, solely as a result of a change in relative market capitalization or index weighting of one or more constituents of the index that the Portfolio is designed to track. Show less