Summary Prospectus by Investment Company - Form 497K

Summary Prospectus dated May 1, 2024

CVT Nasdaq 100^® Index Portfolio

Class I Shares Class F Shares

This Summary Prospectus is designed to provide separate accounts of insurance companies, qualified pension and retirement plans and other eligible investors with key fund information in a clear and concise format. Before you invest, you may want to review the Portfolio's Prospectus and Statement of Additional Information, which contain more information about the Portfolio and its risks. The Portfolio's Prospectus and Statement of Additional Information, both dated May 1, 2024, as may be amended or supplemented, are incorporated by reference into this Summary Prospectus and are available at http://www.calvert.com/variable-portfolios. Contract holders, plan beneficiaries and other investors should ask their financial intermediaries, insurance companies, or plan sponsors, or visit their financial intermediary's or insurance company's web site for more information.

Investment Objective

CVT Nasdaq 100^® Index Portfolio (the "Fund") seeks investment results that correspond to the investment performance of U.S. common stocks, as represented by the Nasdaq-100^® Index.

Fees and Expenses of the Fund

This table does not reflect expenses and charges that are, or may be, imposed under your variable annuity contract or variable life insurance separate account ("Variable Contract") or qualified pension or retirement plan ("Qualified Plan"). If these fees and expenses were included, expenses shown would be higher. For information on these charges, please refer to the applicable Variable Contract prospectus, prospectus summary or disclosure statement. If you participate through a Qualified Plan, the table does not reflect direct expenses of the plan, and you should consult your administrator for more information.

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

Shareholder Fees (fees paid directly from your investment)	Class I	Class F
Maximum Sales Charge (load) Imposed on Purchases (as a percentage of offering price)	None	None
Maximum Deferred Sales Charge (load) (as a percentage of the lower of net asset value at purchase or redemption)	None	None

Annual Fund Operating Expenses (expenses you pay each year as a percentage of the value of your investment)	Class I	Class F
Management Fees	0.42%	0.42%
Distribution and Service (12b-1) Fees	None	0.25%
Other Expenses	0.18%	0.18%
Total Annual Fund Operating Expenses	0.60%	0.85%
Expense Reimbursement(1)	(0.12)%	(0.12)%
Total Annual Fund Operating Expenses After Expense Reimbursement	0.48%	0.73%

(1)

Calvert Research and Management ("CRM") has agreed to reimburse the Fund's expenses to the extent that Total Annual Fund Operating Expenses exceed 0.48% for Class I shares and 0.73% for Class F shares. This expense reimbursement will continue through May 1, 2025. Any amendment to or termination of this reimbursement would require approval of the Board of Directors. The expense reimbursement relates to ordinary operating expenses only and does not include expenses such as brokerage commissions, acquired fund fees and expenses of unaffiliated funds, borrowing costs (including borrowing costs of any acquired funds), taxes or litigation expenses. Amounts reimbursed may be recouped by CRM during the same fiscal year to the extent actual expenses are less than any contractual expense cap in place during such year. Pursuant to this arrangement, CRM may recoup from the Fund any reimbursed expenses during the same fiscal year if such recoupment does not cause the Fund's Total Annual Fund Operating Expenses after such recoupment to exceed (i) the expense limit in effect at the time of the reimbursement; or (ii) the expense limit in effect at the time of recoupment.

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. The Example does not reflect expenses and charges which are, or may be, imposed under your Variable Contract or Qualified Plan. If these fees and expenses were included, expenses shown would be higher. The Example assumes that you invest $10,000 in the Fund 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, that the operating expenses remain the same and that any expense reimbursement arrangement remains in place for the contractual period. 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 I shares	$49	$180	$323	$739
Class F shares	$75	$259	$460	$1,038

Portfolio Turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" the 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 Fund's performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 21% of the average value of its portfolio.

Principal Investment Strategies

The Fund seeks to track the total return of the securities composing the Nasdaq-100^® Index (the "Index"), taking into consideration redemptions, sales of additional shares, and other adjustments described below. Under normal circumstances, the Fund will invest at least 80% of its net assets (plus any borrowings for investment purposes) in investments with economic characteristics similar to the stocks represented in the Index.

The Index is an unmanaged index comprising common stocks of the 100 largest domestic and international non-financial companies on the broader Nasdaq Composite Index based on market capitalization. As of December 31, 2023, the market capitalization of the Index companies ranged from $21.0 billion to $3.0 trillion with a weighted average market capitalization of $882.1 billion. Market capitalizations of companies within the Nasdaq-100^® Index are subject to change. The Index is modified capitalization-weighted, meaning that companies with larger market capitalizations will contribute more to the Index's value than companies with smaller market capitalizations. Except under extraordinary circumstances that may result in an interim evaluation, the Index is rebalanced quarterly, and its composition is reviewed on an annual basis. Replacements to Index constituents are made effective after the close of trading on the third Friday in December. The Fund mirrors the Index's rebalancing process. The Fund is not sponsored, endorsed, sold or promoted by The Nasdaq Group, Inc.

The Fund will invest primarily in common stocks of the companies that compose the Index. The Fund uses a replication index method, investing in the common stock of each company in the Index in approximately the same proportion as represented in the Index itself. The Fund intends to concentrate its investments only to the extent that the Index does. As of December 31, 2023, the Index was concentrated in the information technology sector. While not required, the Fund will generally sell securities that the Index provider removes from the Index. The Fund may also invest in exchange-traded funds ("ETFs") that provide exposure to the Index. Derivatives, such as options and futures, and options on such futures that provide exposure to the stocks in the Index may be held by the Fund incidental to its main investment strategy in order to manage cash balances, to maintain liquidity to meet shareholder redemptions, or minimize trading costs. The Fund may also lend its securities.

The Fund is "non-diversified," which means it may hold securities of a smaller number of issuers and invest a greater percentage of its assets in a particular issuer than a "diversified" fund.

Principal Risks

Market Risk. The value of investments held by the Fund may increase or decrease in response to social, economic, political, financial, public health crises or other disruptive events (whether real, expected or perceived) in the U.S. and global markets and include events such as war, natural disasters, epidemics and pandemics, terrorism, conflicts and social unrest. These events may negatively impact broad segments of businesses and populations and may exacerbate pre-existing risks to the Fund. The frequency and magnitude of resulting changes in the value of the Fund's investments cannot be predicted. Certain securities and other investments held by the Fund may experience increased volatility, illiquidity, or other potentially adverse effects in reaction to changing market conditions. Monetary and/or fiscal actions taken by U.S. or foreign governments to stimulate or stabilize the global economy may not be effective and could lead to high market volatility.

Equity Securities Risk. The value of equity securities and related instruments may decline in response to adverse changes in the economy or the economic outlook; deterioration in investor sentiment; interest rate, currency, and commodity price fluctuations; adverse geopolitical, social or environmental developments; issuer and sector-specific considerations; unexpected trading activity among retail investors; or other factors. Market conditions may affect certain types of stocks to a greater extent than other types of stocks. If the stock market declines in value, the value of the Fund's equity securities will also likely decline. Although prices can rebound, there is no assurance that values will return to previous levels.

Passive Investment Risk. The Fund is managed using a passive investment strategy and expects to hold common stocks of each company in the Index regardless of their current or projected performance. The Fund generally will not adjust its portfolio investments to attempt to take advantage of market opportunities or lessen the impact of a market decline or a decline in the performance of one or more issuers. Maintaining investments regardless of market conditions or the performance of individual investments could cause the Fund's return to be lower than if the Fund employed an active strategy. Unusual market events may increase market volatility and may cause the characteristics of the Index components to vary from those expected under normal circumstances.

Tracking Error Risk. Tracking error risk refers to the risk that the Fund's performance may not match or correlate to that of the Index it attempts to track, either on a daily or aggregate basis. Factors such as Fund expenses, imperfect correlation between the Fund's investments and the Index, rounding of share prices, changes to the composition of the Index, regulatory policies, high portfolio turnover rate and the use of leverage all contribute to tracking error. Tracking error risk may cause the Fund's performance to be less than expected.

Issuer Non-Diversification Risk. The Fund is "non-diversified," which means it may invest a greater percentage of its assets in the securities of a single issuer than a fund that is "diversified." Non-diversified funds may focus their investments in a small number of issuers, making them more susceptible to risks affecting such issuers than a more diversified fund might be, and the value of the Fund's shares may be more volatile than the values of shares of more diversified funds.

Sector Risk. The Fund may invest a significant portion of its assets in one or more sectors, if the Index does so. As such, the value of Fund shares may be affected by events that adversely affect such sector(s), and may fluctuate more than that of a fund that invests more broadly.

Information Technology Sector Risk. The value of Fund shares may be particularly impacted by events that adversely affect the information technology sector, such as rapid changes in technology product cycles, product obsolescence, government regulation, and competition, and may fluctuate more than that of a fund that does not concentrate in companies in the technology sector.

ETF Risk. ETFs are subject to the risks of investing in the underlying securities or other investments. ETF shares may trade at a premium or discount to net asset value and are subject to secondary market trading risks. In addition, the Fund will bear a pro rata portion of the operating expenses of an ETF in which it invests.

Derivatives Risk. The Fund's exposure to derivatives involves risks different from, or possibly greater than, the risks associated with investing directly in securities and other investments. The use of derivatives can lead to losses because of adverse movements in the price or value of the security, instrument, index, currency, commodity, economic indicator or event underlying a derivative ("reference instrument"), due to failure of a counterparty or due to tax or regulatory constraints. Derivatives may create leverage in the Fund, which represents a non-cash exposure to the underlying reference instrument. Leverage can increase both the risk and return potential of the Fund. Derivatives risk may be more significant when derivatives are used to enhance return or as a substitute for a cash investment position, rather than solely to hedge the risk of a position held by the Fund. Use of derivatives involves the exercise of specialized skill and judgment, and a transaction may be unsuccessful in whole or in part because of market behavior or unexpected events. Changes in the value of a derivative (including one used for hedging) may not correlate perfectly with the underlying reference instrument. Derivative instruments traded in over-the-counter markets may be difficult to value, may be illiquid, and may be subject to wide swings in valuation caused by changes in the value of the underlying reference instrument. If a derivative's counterparty is unable to honor its commitments, the value of Fund shares may decline and the Fund could experience delays in (or be unable to achieve) the return of collateral or other assets held by the counterparty. The loss on derivative transactions may substantially exceed the initial investment. A derivative investment also involves the risks relating to the reference instrument underlying the investment.

Foreign Investment Risk. Foreign investments can be adversely affected by political, economic and market developments abroad, including the imposition of economic and other sanctions by the United States or another country against a particular country or countries, organizations, entities and/or individuals. There may be less publicly available information about foreign issuers because they may not be subject to reporting practices, requirements or regulations comparable to those to which United States companies are subject. Adverse changes in investment regulations, capital requirements or exchange controls could adversely affect the value of the Fund's investments. Foreign markets may be smaller, less liquid and more volatile than the major markets in the United States and, as a result, Fund share values may be more volatile. Trading in foreign markets typically involves higher expense than trading in the United States. The Fund may have difficulties enforcing its legal or contractual rights in a foreign country. Depositary receipts are subject to many of the risks associated with investing directly in foreign instruments, including the political and economic risks of the underlying issuer's country and, in the case of depositary receipts traded on foreign markets, currency risk.

Liquidity Risk. The Fund is exposed to liquidity risk when trading volume, lack of a market maker or trading partner, large position size, market conditions, or legal restrictions impair its ability to sell particular investments or to sell them at advantageous market prices. Consequently, the Fund may have to accept a lower price to sell an investment or continue to hold it or keep the position open, sell other investments to raise cash or abandon an investment opportunity, any of which could have a negative effect on the Fund's performance. These effects may be exacerbated during times of financial or political stress.

Securities Lending Risk. Securities lending involves a possible delay in recovery of the loaned securities or a possible loss of rights in the collateral if the borrower fails financially. The Fund could also lose money if the value of the collateral decreases.

General Fund Investing Risks. The Fund is not a complete investment program and there is no guarantee that the Fund will achieve its investment objective. It is possible to lose money by investing in the Fund. The Fund is designed to be a long-term investment vehicle and is not suited for short-term trading. Investors in the Fund should have a long-term investment perspective and be able to tolerate potentially sharp declines in value. Purchase and redemption activities by Fund shareholders may impact the management of the Fund and its ability to achieve its investment objective(s). In addition, the redemption by one or more large shareholders or groups of shareholders of their holdings in the Fund could have an adverse impact on the remaining shareholders in the Fund. The Fund relies on various service providers, including the investment adviser and sub-adviser, if applicable, in its operations and is susceptible to operational, information security and related events (such as public health crises, cyber or hacking attacks) that may affect the service providers or the services that they provide to the Fund. An investment in the Fund is not a deposit in a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Performance

The following bar chart and table provide some indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and how the Fund's average annual returns over time compare with those of one or more indexes intended to measure broad market performance. The Fund's primary benchmark index was changed from the Nasdaq 100^® Index to the S&P 500^® Index effective May 1, 2024 to comply with the regulation that requires the Fund's primary benchmark to represent the overall applicable market. The additional index(es) in the table provide a means to compare the Fund's average annual returns to a benchmark that CRM believes is representative of the Fund's investment universe. The returns in the bar chart are for Class I shares and do not reflect any insurance-related expenses and charges under a Variable Contract or expenses related to a Qualified Plan. If such charges were reflected, the returns would be lower. Thus, you should not compare the Fund's returns directly with the performance of other products without taking into account all insurance-related charges and expenses payable under your Variable Contract or Qualified Plan. Past performance is not necessarily an indication of how the Fund will perform in the future.

CRM became the investment adviser to the Fund on December 31, 2016. Performance reflected prior to such date is that of the Fund's former investment adviser. The Fund's performance reflects the effects of expense reductions. Absent these reductions, performance would have been lower.

For the ten years ended December 31, 2023, the highest quarterly total return for Class I was 30.15% for the quarter ended June 30, 2020 and the lowest quarterly return was -22.36% for the quarter ended June 30, 2022.

Average Annual Total Return as of December 31, 2023	One Year	Five Years	Ten Years
Class I Return Before Taxes	54.40%	22.09%	17.29%
Class F Return Before Taxes	54.02%	21.79%	17.05%
S&P 500® Index (reflects no deduction for fees, expenses or taxes)	26.29%	15.68%	12.03%
Nasdaq 100® Index (reflects no deduction for fees, expenses or taxes)	55.13%	22.65%	17.90%

The Class F performance shown above for the period prior to October 30, 2015 (commencement of operations) is the performance of Class I shares at net asset value without adjustment for any differences in the expenses of the two classes. If adjusted for such differences, returns would be different.

The S&P 500^® Index is a product of S&P Dow Jones Indices LLC or its affiliates ("SPDJI") and any Third Party Licensor, and has been licensed for use by CRM. S&P^®, S&P 500^®, US 500, The 500, iBoxx^®, iTraxx^® and CDX^® are trademarks of S&P Global, Inc. or its affiliates ("S&P"); Dow Jones^® is a registered trademark of Dow Jones Trademark Holdings LLC ("Dow Jones"); any Third Party Licensor Trademarks are trademarks of the Third Party Licensor and these trademarks have been licensed for use by SPDJI and sublicensed for certain purposes by CRM. The Fund is not sponsored, endorsed, sold or promoted by SPDJI, Dow Jones, S&P, their respective affiliates, or any Third Party Licensor and none of such parties make any representation regarding the advisability of investing in such product(s) nor do they have any liability for any errors, omissions, or interruptions of the S&P 500^® Index. Investors cannot invest directly in an Index.

Management

Investment Adviser. Calvert Research and Management ("CRM" or the "Adviser").

Investment Sub-Adviser. Ameritas Investment Partners, Inc. ("AIP").

Portfolio Manager. Kevin L. Keene, CFA, Portfolio Manager of AIP, has managed the Fund since November 2008.

Purchase and Sale of Fund Shares

All purchases, redemptions and exchanges of Fund shares are made through insurance company separate accounts, qualified pension and retirement plans or by other eligible investors that are the record owner of the shares. Contract holders, plan beneficiaries, and other investors seeking to purchase, redeem, or exchange interest in the Fund's shares should consult with the insurance company, plan sponsor or other eligible investor through which their investment in the Fund is made.

Tax Information

The Fund will distribute any net investment income and net realized capital gains at least annually. Both types of distributions will be made in shares of the Fund unless an election is made on behalf of a separate account to receive some or all of the distributions in cash. Because shares of the Fund are offered to insurance company separate accounts, qualified pension and retirement plans, and other eligible investors, you should read your prospectus, disclosure statement or plan documentation to understand the tax treatment of your investment.

Payments to Insurance Companies, Plan Sponsors and Other Financial Intermediaries

The Fund is generally available for purchase by separate accounts of insurance companies, qualified pension and retirement plans or by other eligible investors. The Fund, its principal underwriter and its affiliates may make payments to insurance companies, plan sponsors or other financial intermediaries for distribution and related services. These payments may create a conflict of interest for the insurance company, plan sponsor or other financial intermediary to include the Fund as an investment option in their product or to recommend the Fund over another investment option. Ask your financial intermediary, insurance company, or plan sponsor, or visit your financial intermediary's or insurance company's website, for more information.

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© 2024 Calvert Research and Management

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