Investment Objective

Seeks long-term growth of capital.

Fees and Expenses of the Portfolio

This table describes the fees and expenses that you may pay if you buy, hold, and sell shares of the Portfolio. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the table and example below. The table does not reflect fees or expenses that may be charged in connection with variable annuities and variable life insurance policies issued by the insurance companies which offer the Portfolio as an underlying investment option. If such charges were included, the following fees and expenses would be higher.

Shareholder Fees (fees paid directly from your investment): —

Example. This Example is intended to help you compare the cost of investing your variable contract assets in the Portfolio with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Portfolio for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. The costs indicated below do not reflect the additional expenses of variable contracts. These costs would be higher if variable contract charges were added. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Portfolio Turnover. The Portfolio 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 Example, affect the Portfolio’s performance. During the most recent fiscal year, the Portfolio’s portfolio turnover rate was 41% of the average value of its portfolio.

Principal Investment Strategies

The Portfolio is managed by AllianceBernstein L.P. (“AllianceBernstein”) under a sub-advisory agreement with the Adviser. The Portfolio invests primarily in a diversified portfolio of equity securities with relatively smaller capitalizations as compared to the overall U.S. market. Under normal circumstances, the Portfolio invests at least 80% of its net assets in the equity securities of mid-capitalization companies with public stock market capitalization (based upon shares available for trading on an unrestricted basis) within the range of the market capitalization of companies constituting the Russell Midcap^® Index at the time of investment. As of March 31, 2023, the capitalization range of the Russell Midcap^® Index was between $542.82 million and $58.83 billion. Because the Portfolio’s definition of mid-capitalization companies is dynamic, the limits on market capitalization will change with the markets. In the future, the Portfolio may define mid-capitalization companies using a different classification system.

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In managing the Portfolio, AllianceBernstein diversifies between portions, or “sleeves”, of the Portfolio that utilize active and passive strategies. The Portfolio targets a strategic allocation of 50% of the Portfolio’s net assets to an actively managed sleeve, with the remaining 50% managed in a passive strategy that seeks to track the performance of the Russell Midcap^® Index, an unmanaged securities index, although the allocation may range between 35% - 65%, with the objective of achieving a style balanced portfolio with attractive risk adjusted returns relative to its benchmark, the Russell Midcap^® Index, over full market cycles. The active and passive sleeves are rebalanced back to target weights should they exceed pre-defined thresholds.

Active Sleeve: The Portfolio’s active sleeve is comprised of two components, a US Mid-Cap Growth strategy and a US Mid-Cap Value strategy that are periodically rebalanced back to target weights should they exceed pre-defined thresholds.

US Mid-Cap Growth: The Portfolio’s investment policies emphasize investments in companies that are demonstrating improving financial results and a favorable earnings outlook. The Portfolio may invest in foreign securities.

When selecting securities, AllianceBernstein typically looks for companies that have strong, experienced management teams, strong market positions, and the potential to support greater than expected earnings growth rates. In making specific investment decisions for the Portfolio, AllianceBernstein combines fundamental and quantitative analysis in its stock selection process. The Portfolio may periodically invest in the securities of companies that are expected to appreciate due to a development particularly or uniquely applicable to that company regardless of general business conditions or movements of the market as a whole.

US Mid-Cap Value: The Portfolio invests in companies that are determined by AllianceBernstein to be undervalued, using AllianceBernstein’s fundamental value approach. In selecting securities for the Portfolio’s portfolio, AllianceBernstein uses its fundamental and quantitative research to identify companies whose long-term earnings power is not reflected in the current market price of their securities.

In selecting securities for the Portfolio, AllianceBernstein looks for companies with attractive valuation (for example, with attractive price to free cash flow ratios) and compelling success factors (for example capital discipline and return on equity). AllianceBernstein uses this information to calculate an expected return and ranking. The rankings are used to determine prospective candidates for possible addition to the portfolio. Typically, AllianceBernstein focuses its research on the most attractive 40% of the universe.

AllianceBernstein typically projects a company’s financial performance over a full economic cycle, including a trough and a peak, within the context of forecasts for real economic growth, inflation and interest rate changes. AllianceBernstein focuses on the valuation implied by the current price, relative to the earnings the company will be generating five years from now, or “normalized” earnings, assuming average mid-economic cycle growth for the fifth year.

Generally, a security is sold when it no longer meets appropriate valuation criteria, although sales may be delayed when positive return trends are favorable. Typically, growth in the size of a company’s market capitalization relative to other domestically traded companies will not cause the Portfolio to dispose of the security.

AllianceBernstein seeks to manage overall portfolio volatility relative to the universe of companies that comprise the lowest 20% of the total U.S. market capitalization by favoring promising securities that offer the best balance between return and targeted risk. At times, the Portfolio may favor or disfavor a particular sector compared to that universe of companies. The Portfolio may invest significantly in companies involved in certain sectors that constitute a material portion of the universe of small- and mid-capitalization companies.

Passive Sleeve: The Portfolio’s passive component seeks to track the Russell Midcap^® Index (the “Index”) using a representative sampling of Index constituents, and rebalances annually on the same schedule as the Index, as well as quarterly to add eligible IPOs, also on the same schedule as the Index. The Index seeks to measure the mid-cap segment of the US equity market and employs a free-float adjusted market capitalization-weighted approach.

Derivatives

The Portfolio invests principally in equity securities but may also invest in other types of securities, such as preferred stocks. The Portfolio, at times, invests in shares of exchange-traded funds (“ETFs”) in lieu of making direct investments in securities. ETFs may provide more efficient and economical exposure to the types of companies and geographic locations in which the Portfolio seeks to invest than direct investments. The Portfolio may also invest up to 20% of its total assets in rights and warrants, which are instruments that entitle the holder to purchase an equity security at a specific price for a specific period of time.

The Portfolio may enter into derivatives transactions, such as options, futures contracts, forwards and swaps to manage risk and to seek to generate additional returns. The Portfolio may use options strategies involving the purchase and/or writing of various combinations of call and/or put options, including on individual securities and stock indices, futures contracts (including futures

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contracts on individual securities and stock indices) or shares of ETFs. These transactions may be used, for example, in an effort to earn extra income, to adjust exposure to individual securities or markets, or to protect all or a portion of the Portfolio’s portfolio from a decline in value, sometimes within certain ranges.

Principal Risks

There is no assurance that the Portfolio will meet its investment objective. The value of your investment in the Portfolio and the amount of the return you receive on your investment may fluctuate significantly. You could lose money, or have less return than the market in general, by investing in the Portfolio. The principal risks of investing in the Portfolio are:

Market Risk — A security’s price may change in response to changes in conditions in securities markets in general. Markets tend to move in cycles with periods of rising prices and periods of falling prices. They can decline for many reasons, including adverse political or economic developments domestically or abroad, changes in investor psychology, or heavy institutional selling. Different types of stocks sometimes shift into and out of favor with investors. For example, at times the market may not favor growth-oriented stocks. Instead, it might favor value stocks or not favor stocks at all. If the Portfolio focuses on a particular investment style, its performance will sometimes be better or worse than the performance of funds focusing on other types of investments. A significant national or international event, natural disaster or widespread health crisis, such as the COVID-19 global pandemic, could cause substantial market volatility, exchange trading suspensions and closures, severe market dislocations and liquidity constraints, impact the ability to complete redemptions, and affect the Portfolio’s performance.

Medium Capitalization Company Risk — Medium capitalization company stock prices tend to be more volatile, and the stock tends to be less liquid than those of larger, better established companies. Medium capitalization companies are also sometimes more subject to failure.

Growth Strategy Risk — Growth stocks may be more volatile than other stocks because they are generally more sensitive to investor perceptions of the issuing company’s growth of earnings potential. Also, since growth companies usually invest a high portion of earnings in their business, growth stocks may lack the dividends of value stocks that can cushion stock prices in a falling market.

Value Strategy Risk — Because the portfolio managers are assessing intrinsic value of companies, their assessment of value may be incorrect and the securities may be appropriately priced by the market. In such cases the expected return for such securities may be lower than expected.

Issuer Risk — The value of a security may decline for reasons related to the issuer, such as earnings stability, overall financial soundness, management performance and reduced demand for the issuer’s goods or services.

Foreign Investments Risk — Foreign investments involve risks not normally encountered with domestic securities. These include political, regulatory and economic instability in some countries, the imposition of economic sanctions, changes in currency rates and market inefficiencies. The laws of some foreign countries may limit the Portfolio’s ability to invest in securities of certain issuers organized under the laws of those countries. Trade tensions and economic sanctions on individuals and companies can contribute to market volatility. This may adversely impact the Portfolio’s performance.

Currency Risk — Exchange rates for currencies fluctuate daily. The Portfolio’s net asset value and returns may experience increased volatility as a result of its exposure to foreign currencies through direct holdings of such currencies or holdings of non-U.S. dollar denominated securities.

Sector Risk — A certain sector may not perform as well as companies in other sectors or the market as a whole. When the Portfolio concentrates its investments in a sector, it is more susceptible to any adverse economic, business or other developments generally affecting companies in that sector.

Management Risk — The Portfolio is subject to management risk because it is an actively-managed investment fund. AllianceBernstein will apply its investment techniques and risk analyses in making investment decisions, but there is no guarantee that its techniques will produce the intended results. Some of these techniques may incorporate, or rely upon, quantitative models, but there is no guarantee that these models will generate accurate forecasts, reduce risk or otherwise perform as expected.

Passive Investment Risk — A passive investment strategy attempts to track the performance of an unmanaged index of securities and differs from an actively managed fund which typically seeks to outperform a benchmark index. A component of the Portfolio is managed with a passive investment strategy that seeks to track the index and its performance could be lower than actively managed funds that may shift their portfolio assets in response to changes in the market such as taking advantage of market opportunities or to lessen the impact of a market decline. As the Portfolio attempts to track the performance of the index, the structure and composition of the index will have an impact on the performance, volatility and risk of the Portfolio. The performance of the Portfolio may be lower than the index as a result of transaction costs related to index rebalances and cash flows.

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Tracking Risk — The passive component of the Portfolio’s return may not match the return of the Index for a number of reasons, including: the Portfolio incurs operating expenses not applicable to the Index, and incurs costs in buying and selling securities; the Portfolio may not be fully invested at times; the performance of the Portfolio and the Index may vary due to asset valuation differences and differences between the Portfolio’s portfolio and the Index resulting from legal restrictions, cost or liquidity constraints and; if used, representative sampling may cause the Portfolio’s tracking error to be higher than would be the case if the Portfolio purchased all of the securities in the Index.

Exchange-Traded Funds Risk — ETF shares may trade at a discount or premium to their NAV. Because the value of ETF shares depends on the demand in the market, the sub-adviser may not be able to liquidate the Portfolio’s holdings at the most optimal time, adversely affecting performance. ETFs in which a Portfolio invests will not be able to replicate exactly the performance of the indices they track, if any, because the total return generated by the securities will be reduced by transaction costs incurred in adjusting the actual balance of the securities. In addition, the ETFs in which the Portfolio invests will incur expenses not incurred by their applicable indices. Each ETF is subject to specific risks, depending on the nature of the fund.

Derivatives Risk — Derivatives can be highly volatile and involve risks in addition to the risks of the underlying referenced securities. Using derivatives can increase fund losses and reduce opportunities for gains when market prices, interest rates or the derivative instruments themselves behave in a way not anticipated by the Portfolio. Derivatives may be difficult to sell, unwind or value, and the counterparty may default on its obligations to the Portfolio. Changes in the value of the derivative may not correlate perfectly with the underlying asset, rate or index and the Portfolio could lose more than the principal amount invested. In addition to investing in derivatives to implement its strategy, the Portfolio may also use derivative instruments for hedging purposes, in an attempt to reduce the risk of loss from falling stock prices or lower foreign currency valuations, increased interest rates or other adverse market developments. There can be no assurance that a hedging technique will work as intended. Portfolio performance may be diminished by the added cost of the derivative instruments.

Warrant and Rights Risk — If the underlying stock price does not rise above the exercise price before the warrant expires, a warrant generally expires without value and the Portfolio loses any amount paid for the warrant. Warrants may trade in the same markets as their underlying stock; however, the price of a warrant may not move with the price of the underlying stock. Failing to exercise subscription rights to purchase common stock would dilute the Portfolio’s interest in the issuing company. The market for such rights is not well developed, and the Portfolio may not always realize full value on the sale of rights.

Futures Risk — The Portfolio’s use of futures involves risks different from, or possibly greater than, the risks associated with investing directly in securities and other traditional investments. These risks include: (i) leverage risk; (ii) risk of mispricing or improper valuation; and (iii) risk that changes in the value of the futures contract may not correlate perfectly with the underlying index. Investments in futures involve leverage, which means a small percentage of assets invested in futures can have a disproportionately large impact on the Portfolio. This risk could cause the Portfolio to lose more than the principal amount invested. Additionally, changes in the value of futures contracts may not track or correlate perfectly with the underlying index because of temporary, or even long-term, supply and demand imbalances and because futures do not pay dividends unlike the stocks upon which they are based.

Options Risk — Risks specific to investments in call options include limited gains and lack of liquidity. By selling a call option, the Portfolio may forego the opportunity to participate in price increases for the underlying equities above the exercise price, while still bearing the risk of a decline in the value of the underlying equities or index. As the buyer of a call option, the Portfolio risks losing the entire premium invested in the option if the underlying equity or index does not rise above the option strike price. As the buyer of a put option, the Portfolio risks losing the entire premium invested in the option if the underlying equity or index does not fall below the option strike price. By selling a put option, the Portfolio bears the risk of a decline in the value of the underlying equities or index. Losses on the sale of a put option are unlimited.

There may not be a liquid market for options. Lack of liquidity may prevent the Portfolio from closing out an option position, written or purchased, at an opportune time or price. Because the Portfolio will generally hold the equities underlying a call option or exposure to the index underlying the option, the Portfolio may be less likely to sell the stocks it is holding to take advantage of new investment opportunities.

Swap Risk — Swaps are subject to tracking risk because they may not be perfect substitutes for the instruments they are intended to hedge or replace. Over the counter swaps are subject to counterparty default. Leverage inherent in derivatives will tend to magnify the Portfolio’s losses.

Preferred Stock Risk — The prices of preferred stock typically respond to interest rate changes, decreasing in value if interest rates rise and increasing in value if interest rates fall. Preferred stocks are also subject to credit risk, which is the possibility that an issuer of preferred stock will fail to make its dividend payments. Preferred stock prices tend to move upwards more slowly than common stock prices.

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Performance

The accompanying bar chart and table provide some indication of the risks of investing in the Portfolio. They show changes in the Portfolio’s performance for each of the last ten years and the Portfolio’s average annual returns for the last one year, five years and ten years compared to those of a broad-based securities market index. The Portfolio’s past performance does not necessarily indicate how it will perform in the future. Variable contract charges are not reflected in the chart or table. If they were, the returns would be less than those shown.

AllianceBernstein began sub-advising the Portfolio under its current strategy effective May 1, 2021. Prior to December 2009, this Portfolio was sub-advised by RS Investment Management Co. LLC. From December 2009 through April 30, 2018, the Portfolio was sub-advised by GSAM. From May 1, 2018 through April 30, 2021, the Portfolio was sub-advised by Janus. Performance returns shown below for periods prior to May 1, 2021 are not indicative of returns of the current strategy or sub-adviser.

During the period shown in the bar chart, the Portfolio’s highest return for a quarter was 24.09%. That was the quarter ended on June 30, 2020. The lowest return for a quarter was -26.09%. That was the quarter ended on March 31, 2020. To obtain performance information up to the most recent month end, call toll free 877.781.6392.

Management

Ohio National Investments, Inc. serves as the investment adviser for the Portfolio. AllianceBernstein serves as the investment sub-adviser of the Portfolio. Joshua Lisser, Head of Index Strategies at AllianceBernstein, Nelson Yu, CFA, Head of Quantitative Research and Blend Strategies at AllianceBernstein, Bruce K. Aronow*, CFA, Chief Investment Officer for Small and SMID Cap Growth Equities at AllianceBernstein, Samantha S. Lau. CFA, Co-Chief Investment Officer for Small and SMID Cap Growth Equities at AllianceBernstein, James MacGregor, CFA, Chief Investment Officer for US Small and Mid Cap Value Equities and Head of US Value Equities at AllianceBernstein, and Erik Turenchalk, CFA, Portfolio Manager, US Small and Mid Cap Value Equities at AllianceBernstein, have been Portfolio Managers of the Portfolio since May 2021.

Purchase and Sale of Fund Shares

Shares of the Portfolio are offered only to separate accounts of insurance companies, which use the Portfolio shares as an underlying investment for variable annuities and variable life insurance contracts, and to portfolios of the Fund in connection with ONLIC, ONLAC and National Security’s variable annuity contracts and variable life insurance policies. You may select funds and make transfers among fund options as described in your variable contract prospectus. The separate accounts of the insurance companies may purchase and redeem Portfolio shares, at their net asset value next computed, each day the New York Stock Exchange is open for unrestricted trading. Please read your variable contract prospectus for more information about your variable contract.

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Tax Information

The tax treatment of payments made from a variable contract is described in the contract’s prospectus. Generally, contract owners are not taxed on income or gains realized within their contract until they receive payments from the contract.

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