Strategy. In pursuing its investment objective, the Portfolio normally invests at least 80% of its assets (net assets plus any borrowings made for investment purposes) in equity securities of companies that are associated with natural resources companies, including those companies that are principally engaged in the research, development, manufacturing, extraction, distribution or sale of materials, energy, or goods related to the agriculture, energy, materials, or commodity-related industrials sectors. The Portfolio may also invest up to 50% of its total assets in foreign and emerging markets securities, including American Depositary Receipts (ADRs) and securities of companies in developing countries, which offer increasing opportunities for natural resource-related growth. Additionally, the Portfolio may invest in debt securities, including up to 10% of its total … Show more… In pursuing its investment objective, the Portfolio normally invests at least 80% of its assets (net assets plus any borrowings made for investment purposes) in equity securities of companies that are associated with natural resources companies, including those companies that are principally engaged in the research, development, manufacturing, extraction, distribution or sale of materials, energy, or goods related to the agriculture, energy, materials, or commodity-related industrials sectors. The Portfolio may also invest up to 50% of its total assets in foreign and emerging markets securities, including American Depositary Receipts (ADRs) and securities of companies in developing countries, which offer increasing opportunities for natural resource-related growth. Additionally, the Portfolio may invest in debt securities, including up to 10% of its total assets in debt securities rated below investment grade. The Portfolios subadviser, T. Rowe Price Associates, Inc. (T. Rowe Price), invests primarily in the common stocks of natural resource companies whose earnings and tangible assets could benefit from accelerating inflation. The Portfolio also may invest in other growth companies that T. Rowe Price believes have strong potential for earnings growth but do not own or develop natural resources. The relative percentages invested in natural resource and non-natural resource companies can vary depending on economic and monetary conditions and the Portfolios subadvisers outlook for inflation. Natural resource companies in which the Portfolio invests typically own, develop, refine, service or transport resources, including energy, metals, forest products, industrials, utilities, chemicals, real estate, and other basic commodities that can be produced and marketed profitably when both labor costs and prices are rising. In pursuing its investment objective, the Portfolio has the discretion to deviate from its normal investment criteria and purchase securities that the subadviser believes will provide an opportunity for substantial appreciation. These situations might arise when the subadviser believes a security could increase in value for a variety of reasons, including an extraordinary corporate event, a new product introduction or innovation, a favorable competitive development, or a change in management. The Portfolio may also invest in other investment companies, including exchange-traded funds, and illiquid investments. Show less