Putnam VT Focused U.S. Research Fund

Putnam

VT Focused U.S.

Research Fund



Summary Prospectus		October 5, 2026



Class IA (-), Class IB (-)

Before you invest, you may want to review the fund’s prospectus, which contains more information about the fund and its risks. You can find the fund’s prospectus, statement of additional information, reports to shareholders and other information about the fund online at www.franklintempleton.com/prospectus. You can also get this information at no cost by calling 1-800-225-1581 or by sending an e-mail request to funddocuments@putnam.com.

The fund’s prospectus and statement of additional information, both dated October 5, 2026, as may be supplemented, are all incorporated by reference into this Summary Prospectus.

Prior to October 5, 2026, Putnam VT Focused U.S. Research Fund was named Putnam VT Sustainable Leaders Fund.

Goal

The fund seeks long-term capital appreciation.

Fees and expenses

The following table describes the fees and expenses you may pay if you buy, hold and sell shares of the fund. 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. The fees and expenses information does not reflect insurance-related charges or expenses borne by contract holders indirectly investing in the fund. If it did, expenses would be higher.

Annual Fund Operating Expenses

(expenses you pay each year as a percentage of the value of your investment)



Share class	Management fees	Distribution and service (12b-1) fees	Other expenses	Total annual fund operating expenses
Class IA	0.53%	None	0.10%	0.63%
Class IB	0.53%	0.25%	0.10%	0.88%

Example

The following hypothetical example is intended to help you compare the cost of investing in the fund with the cost of investing in other funds. The example does not reflect insurance-related charges or expenses. If it did, expenses would be higher. It assumes that you invest $10,000 in the fund for the time periods indicated and then redeem or hold all your shares at the end of those periods. It assumes a 5% return on your investment each year and that the fund’s operating expenses remain the same (except that any applicable fee waiver or expense reimbursement is reflected only through its expiration date). Your actual costs may be higher or lower.


Share class	1 year	3 years	5 years	10 years
Class IA	$64	$201	$350	$786
Class IB	$90	$281	$488	$1,084

Portfolio turnover

The fund pays transaction-related costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher turnover rate may indicate higher transaction costs. These costs, which are not reflected in annual fund operating expenses or the above example, affect fund performance. The fund’s turnover rate in the most recent fiscal year was 43%.

Investments, risks, and performance

Investments

The fund invests mainly in equity securities (growth or value stocks or both) of large and midsize companies that the Investment Manager, as defined below, believes have favorable investment potential, although the Investment Manager anticipates that the fund will invest to a greater extent in large companies than in midsize companies. The Investment Manager may consider, among other factors, a company’s valuation, financial strength, growth potential, competitive position in its industry, projected future earnings, cash flows and dividends when deciding whether to buy or sell investments. Under normal circumstances, the fund invests at least 80% of its net assets (plus the amount of borrowings for investment purposes, if any) in equity securities of companies located in the United States. This policy may be changed only after 60 days’ notice to shareholders. The Investment Manager considers a company to be located in the United States if the company’s securities trade in the United States, the company is headquartered or organized in the United States or the company derives a majority of its revenues or profits in the United States. Equity securities include common stocks, preferred stocks, convertible securities, warrants, American Depositary Receipts (“ADRs”) and Global Depositary Receipts (“GDRs”).

From time to time, the fund may invest a significant portion of its assets in companies in one or more related industries or sectors.

The fund is “non-diversified,” which means it may invest a greater percentage of its assets in fewer issuers than a “diversified” fund. The fund expects to invest in a limited number of issuers.

Risks

It is important to understand that you can lose money by investing in the fund.

Market risk: The value of investments in the fund’s portfolio may fall or fail to rise over extended periods of time for a variety of reasons, including general economic, political or financial market conditions, investor sentiment and market perceptions, government actions, geopolitical events or changes, outbreaks of infectious illnesses or other widespread public health issues, and factors related to a specific issuer, asset class, geography, industry or sector. These and other factors may lead to increased volatility and reduced liquidity in the fund’s portfolio holdings, may negatively impact the fund’s performance, and may exacerbate other risks to which the fund is subject.

Common stock risk: Common stock represents an ownership interest in a company. The value of a company’s stock may fall or fail to rise as a result of factors directly relating to that company, such as decisions made by its management or lower demand for the company’s products or services. A stock’s value may also fall because of factors affecting not just the company, but also other companies in the same industry or in a number of different

industries, such as increases in production costs. Companies whose stocks the Investment Manager believes are undervalued by the market may have experienced adverse business developments or may be subject to special risks that have caused their stocks to be out of favor. Growth stocks may be more susceptible to earnings disappointments, and value stocks may fail to rebound. The fund will be more susceptible to these risks than other funds because it concentrates its investments in a limited number of issuers or sectors, and the fund may perform poorly as a result of adverse developments affecting those issuers or sectors. These risks are generally greater for small and midsize companies.

Industry or sector focus risk: From time to time, the fund may invest a significant portion of its assets in companies in one or more related industries or sectors, which would make the fund more vulnerable to adverse developments affecting those industries or sectors. For example, the fund may invest a significant portion of its assets in companies in the information technology sector that may be significantly affected by technological obsolescence or innovation, short product cycles, falling prices and profits, competitive pressures and general market conditions.

Non-diversified risk: As a non-diversified fund, the fund invests in fewer issuers and is more vulnerable than a more broadly diversified fund to fluctuations in the values of the securities it holds. Moreover, the gains and losses on a single investment may have a greater impact on the fund’s net asset value and may make the fund more volatile than more diversified funds.

Large shareholder transaction risk: The fund is subject to the risk that shareholders will purchase or redeem large quantities of shares of the fund. The fund may be an investment option for mutual funds that are managed by the Investment Manager and its affiliates as “funds of funds.” Additionally, other investors from time to time may make substantial investments in the fund. Such shareholders may at times be considered to control the fund. In addition, a large number of shareholders may collectively purchase or redeem fund shares in large amounts rapidly or unexpectedly. Large shareholder transactions may adversely affect the fund’s liquidity and net assets. These redemptions may also adversely affect the fund’s performance if the fund is forced to sell securities, which may also increase the fund’s brokerage costs.

Management and operational risk: There is no guarantee that the investment techniques, analyses, or judgments that the Investment Manager applies in making investment decisions for the fund will produce the intended outcome or that the investments selected for the fund will perform as well as other securities that were not selected for the fund. The Investment Manager, or the fund’s other service providers, may experience disruptions or operating errors that could negatively impact the fund.

The fund may not achieve its goal, and it is not intended to be a complete investment program. An investment in the fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Cybersecurity risk: Cybersecurity incidents, both intentional and unintentional, may allow an unauthorized party to gain access to fund assets, fund or customer data (including private shareholder information), or proprietary information, cause the fund, the Investment Manager and/or their service providers (including, but not limited to, fund accountants, custodians, sub-custodians, transfer agents and financial intermediaries) to suffer data breaches, data corruption or loss of operational functionality or prevent fund investors from purchasing, redeeming, or exchanging shares, or receiving distributions. The fund and the Investment Manager have limited ability to prevent or mitigate cybersecurity incidents affecting third party service providers, and such third party service providers may have limited indemnification obligations to the fund and/or the Investment Manager. Cybersecurity incidents may result in financial losses to the fund and its shareholders, and substantial costs may be incurred in an effort to prevent or mitigate future cybersecurity incidents. Issuers of securities in which the fund invests are also subject to cybersecurity risks, and the value of these securities could decline if the issuers experience cybersecurity incidents.

Because technology continues to evolve rapidly, including through developments in artificial intelligence and machine learning, new methods of carrying out cyber-attacks continue to emerge. As a result, certain cybersecurity risks may not yet be identified and some cyber-attacks may not be detected promptly, which may limit the fund’s ability to anticipate, prepare for or respond effectively to a cybersecurity incident. Like other funds and business enterprises, the fund, the Investment Manager and their service providers are subject to the risk of cybersecurity incidents from time to time. The rapid development and increasingly widespread use of artificial intelligence technologies may increase the sophistication and effectiveness of cyber attacks, which may exacerbate these risks.

Performance

The accompanying bar chart and table provide some indication of the risks of investing in the fund. The bar chart shows changes in the fund’s performance from year to year for Class IA shares. The table shows the average annual total returns of each class of the fund that has been in operation for at least one full calendar year and also compares the fund’s performance with the average annual total returns of a broad measure of market performance, an additional index with characteristics relevant to the fund and the Linked S&P 500 Index, which represents the performance of the Russell 3000^® Growth Index through August 31, 2019, and the performance of the S&P 500^® Index thereafter. On April 30, 2018 and again on October 5, 2026, the fund materially changed its investment strategy and may have achieved materially different performance results under its current investment strategy than it achieved under the investment strategies in effect before those dates. Performance for classes other than those shown may vary from the performance shown to the extent the expenses for those classes differ. The fund makes updated

performance information, including its current net asset value per share, available at www.franklintempleton.com.

The fund’s past performance (before and after taxes) is not necessarily an indication of how the fund will perform in the future.

Insurance-related charges or expenses are not reflected in the performance information below, and if those charges were included, returns would be less than those shown.

Annual total returns for class IA shares

LOGO


Best Quarter:	Q2 2020	24.12%
Worst Quarter:	Q2 2022	-17.79%
As of June 30, 2026, the fund’s year-to-date return was 4.21%.

Average annual total returns

(for periods ended 12/31/25)


Share class	1 year			5 years			10 years
Class IA		10.99	%		10.62	%		14.98	%
Class IB		10.69	%		10.34	%		14.69	%
Russell 3000 Index (no deduction for fees, expenses or taxes)		17.15	%		13.15	%		14.29	%
S&P 500 Index (no deduction for fees, expenses or taxes)		17.88	%		14.42	%		14.82	%
Linked S&P 500 Index (no deduction for fees, expenses or taxes)		17.88	%		14.42	%		15.75	%

Important data provider notices and terms are available at www.franklintempletondatasources.com. Such information is subject to change.

Your fund’s management

Investment Manager

Putnam Investment Management, LLC (“Putnam Management” or the “Investment Manager”)

Sub-advisors

Franklin Advisers, Inc. (“Franklin Advisers”)

Franklin Templeton Investment Management Limited (“FTIML”)

Portfolio managers

Jacquelyne J. Cavanaugh