Putnam VT Small Cap Growth Fund*

*Prior to September 17, 2018, the fund was known as Putnam VT Capital Opportunities Fund.

Before you invest, you may wish to review the fund’s prospectus, which contains more information about the fund and its risks. You may obtain the prospectus and other information about the fund, including the statement of additional information (SAI) and most recent reports to shareholders, at no cost by visiting putnam.com/individual/annuities, calling 1-800-225-1581, or e-mailing Putnam at funddocuments@putnam.com.

The fund’s prospectus and SAI, both dated 9/17/18, are incorporated by reference into this summary prospectus.

Fund summary

Goal

Putnam VT Small Cap Growth Fund seeks capital appreciation.

Fees and expenses

The following table describes the fees and expenses you may pay if you buy and hold shares of the fund. 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)

							Total
							annual
							fund
							operating
		Distri-			Total		expenses
		bution		Acquired	annual		after
		and		fund	fund	Expense	expense
	Manage-	service		fees	opera-	reim-	reim-
	ment	(12b-1)	Other	and	ting	burse-	burse-
Share class	fees	fees	expenses	expenses	expenses	ment#	ment
Class IA	0.62%	N/A	0.39%	0.07%	1.08%	(0.11)%	0.97%
Class IB	0.62%	0.25%	0.39%	0.07%	1.33%	(0.11)%	1.22%

# Reflects Putnam Investment Management, LLC’s contractual obligation to limit certain fund expenses through 4/30/20. This obligation may be modified or discontinued only with approval of the fund’s Board of Trustees.

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. Only the first year of each period in the example takes into account the expense reimbursement described above. Your actual costs may be higher or lower.

Share class	1 year	3 years	5 years	10 years
Class IA	$99	$333	$585	$1,307
Class IB	$124	$411	$718	$1,592

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 157%.

Investments, risks, and performance

Investments

We invest mainly in common stocks of small U.S. companies, with a focus on growth stocks. Growth stocks are issued by companies whose earnings are expected to grow faster than those of similar firms, and whose business growth and other characteristics may lead to an increase in stock price. Under normal circumstances, we invest at least 80% of the fund’s net assets in companies of a size similar to those in the Russell 2000 Growth Index. This policy may be changed only after 60 days’ notice to shareholders. As of August 31, 2018, the index was composed of companies having market capitalizations of between approximately $32.78 million and $8.31 billion. We 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.

Risks

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

The value of stocks in the fund’s portfolio may fall or fail to rise over extended periods of time for a variety of reasons, including general financial market conditions, changing market perceptions, changes in government intervention in the financial markets, and factors related to a specific issuer, industry or sector. These and other factors may lead to increased volatility and reduced liquidity in the fund’s portfolio holdings. Growth stocks may be more susceptible to earnings disappointments, and the market may not favor growth-style investing. These risks

Summary prospectus of the Trust   1 

are generally greater for small and midsize companies. 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.

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.

Performance

The performance information below gives some indication of the risks associated with an investment in the fund by showing the fund’s performance year to year and over time. Before September  17, 2018, the fund was managed with a materially different investment strategy and may have achieved materially different performance results under its current investment strategy from that shown for periods before this date. The performance information does not reflect insurance-related charges or expenses. If it did, performance would be lower. Please remember that past performance is not necessarily an indication of future results.

Average annual total returns
(for periods ended 12/31/17)

Share class	1 year	5 years	10 years
Class IA	8.26%	10.86%	8.33%
Class IB	7.93%	10.58%	8.06%
Russell 2000 Growth Index*
(no deduction for fees or expenses)	22.17%	15.21%	9.19%

* Frank Russell Company is the source and owner of the trademarks, service marks and copyrights related to the Russell Indexes. Russell® is a trademark of Frank Russell Company. As of September 17, 2018, the Russell 2000 Growth Index replaced the Russell 2500 Index as the primary benchmark for this fund because, in Putnam Investment Management, LLC’s opinion, the securities tracked by this index more accurately reflect the types of securities that generally will be held by the fund. The average annual total returns of the Russell 2500 Index for the one-year, five-year and ten-year periods ended December 31, 2017 were 16.81%, 14.33% and 9.22%, respectively.

Your fund’s management

Investment advisor

Putnam Investment Management, LLC

Portfolio manager

William Monroe, Portfolio Manager, portfolio manager of the fund since 2018

Sub-advisor

Putnam Investments Limited*

* Though the investment advisor has retained the services of Putnam Investments Limited (PIL), PIL does not currently manage any assets of the fund.

Purchase and sale of fund shares

Fund shares are offered to separate accounts of various insurers. The fund requires no minimum investment, but insurers may require minimum investments from those purchasing variable insurance products for which the fund is an underlying investment option. Insurers may purchase or sell shares on behalf of separate accounts by submitting an order to Putnam Retail Management any day the New York Stock Exchange (NYSE) is open. Some restrictions may apply.

Tax information

Generally, owners of variable insurance contracts are not taxed currently on income or gains realized with respect to such contracts. However, some distributions from such contracts may be taxable at ordinary income tax rates and distributions to contract owners younger than 59½ may be subject to a 10% penalty tax. For more information, please see the prospectus (or other offering document) for your variable insurance contract.

Payments to insurance companies

The fund is offered as an underlying investment option for variable insurance contracts. The fund and its related companies may make payments to the sponsoring insurance company (or its affiliates) and dealers for distribution and/or other services. These payments may create an incentive for the insurance company to include the fund, rather than another investment, as an option in its products and may create a conflict of interest for dealers in recommending the fund over another investment. The prospectus (or other offering document) for your variable insurance contract may contain additional information about these payments.

Information about the Summary Prospectus, Prospectus, and SAI

The summary prospectus, prospectus, and SAI for a fund provide information concerning the fund. The summary prospectus, prospectus, and SAI are updated at least annually and any information provided in a summary prospectus, prospectus, or SAI can be changed without a shareholder vote unless specifically stated otherwise. The summary prospectus, prospectus, and the SAI are not contracts between the fund and its shareholders and do not give rise to any contractual rights or obligations or any shareholder rights other than any rights conferred explicitly by federal or state securities laws that may not be waived.

Additional information is available at putnam.com/individual/annuities, by calling 1-800-225-1581, or by e-mailing Putnam at funddocuments@putnam.com.

File No. 811-05346    VTBP068   312660  9/18 

2  Summary prospectus of the Trust