Putnam Variable Trust N-CSR Certified annual shareholder report (management investment company)

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM N-CSR

CERTIFIED SHAREHOLDER REPORT OF REGISTERED
MANAGEMENT INVESTMENT COMPANIES

Investment Company Act file number: (811-05346)

Exact name of registrant as specified in charter: Putnam Variable Trust

Address of principal executive offices: 100 Federal Street, Boston, Massachusetts 02110

Name and address of agent for service: Robert T. Burns, Vice President
100 Federal Street
Boston, Massachusetts 02110

Copy to:         Bryan Chegwidden, Esq.
Ropes & Gray LLP
1211 Avenue of the Americas
New York, New York 10036

Registrant’s telephone number, including area code: (617) 292-1000

Date of fiscal year end: December 31, 2018

Date of reporting period : January 1, 2018 — December 31, 2018

Item 1. Report to Stockholders:

The following is a copy of the report transmitted to stockholders pursuant to Rule 30e-1 under the Investment Company Act of 1940:

Message from the Trustees

February 12, 2019

Dear Shareholder:

Global financial markets encountered challenges in the final months of 2018. December was difficult for stock markets worldwide, and most major indexes finished the year with losses. Among the issues that contributed to the downturn were uncertainty about monetary policy, a slowing Chinese economy, and the U.S.–China trade dispute. Fixed-income markets were less volatile than stocks, and higher quality bonds benefited from a flight to safety amid the turmoil.

Although no one can predict the direction of the markets in the months ahead, Putnam’s experienced investment professionals actively seek to position their fund portfolios for all types of conditions. They take a research-intensive approach to investing that includes risk management strategies designed to serve investors through changing markets. In all environments, we believe investors should remain focused on time-tested approaches: maintain a well-diversified portfolio, think about long-term goals, and speak regularly with a financial advisor.

Thank you for investing with Putnam.

Performance summary(as of 12/31/18)

Investment objective

As high a rate of current income as Putnam Investment Management, LLC, believes is consistent with preservation of capital and maintenance of liquidity

Net asset valueDecember 31, 2018

Class IA: $1.00  Class IB: $1.00 

Total return at net asset value

			Lipper VP
			(Underlying
			Funds) — Money
(as of 12/31/18)	Class IA shares*	Class IB shares†	Market Funds
1 year	1.43%	1.18%	1.31%
5 years	1.94	1.46	1.78
Annualized	0.39	0.29	0.35
10 years	2.37	1.74	2.15
Annualized	0.23	0.17	0.21
Life	153.58	147.00	153.95
Annualized	3.06	2.97	3.07
Current rate(as of 12/31/18)
Current 7-day
yield	2.03%	1.78%

For a portion of the periods, the fund had expense limitations, without which returns would have been lower.

* Class inception date: February 1, 1988.

† Class inception date: April 30, 1998.

The 7-day yield is the most common gauge for measuring money market mutual fund performance. Yield reflects current performance more closely than total return.

Data represent past performance. Past performance does not guarantee future results. More recent returns may be less or more than those shown. Investment return and principal value will fluctuate, and you may have a gain or a loss when you sell your shares. Performance information does not reflect any deduction for taxes a shareholder may owe on fund distributions or on the redemption of fund shares. All total return figures are at net asset value and exclude contract charges and expenses, which are added to the variable annuity contracts to determine total return at unit value. Had these charges and expenses been reflected, performance would have been lower. Performance of class IB shares before their inception is derived from the historical performance of class IA shares, adjusted to reflect the higher operating expenses applicable to such shares. For more recent performance, contact your variable annuity provider who can provide you with performance that reflects the charges and expenses at your contract level.

Allocations are shown as a percentage of the fund’s net assets. Cash and net other assets, if any, represent the market value weights of cash and other unclassified assets in the portfolio. Summary information may differ from the portfolio schedule included in the financial statements due to the inclusion of any interest accruals, the exclusion of as-of trades, if any, the use of different classifications of securities for presentation purposes, and rounding. Holdings and allocations may vary over time.

Putnam VT Government Money Market Fund  1 

Report from your fund’s managers

How was the money-market environment for the 12-month reporting period ended December 31, 2018, and how did the fund perform?

The year began with solid U.S. economic growth, strong corporate earnings, and tax reform contributing to rising consumer, business, and investor confidence. However, volatility picked up during the first quarter and continued for much of 2018, as higher interest rates, concerns about the U.S.–China trade war, and other geo-political worries weighed on investor sentiment. The fourth quarter was especially volatile, resulting in a flight to safety that increased demand for refuge assets, including money market funds.

The Federal Reserve continued to gradually reduce its accommodative monetary policy. The central bank allowed $10 billion per month in Treasury and mortgage securities to mature until October, when it boosted the amount to a planned maximum amount of $50 billion a month. The Fed also increased the federal funds rate in March, June, September, and December — raising the cost of borrowing money for consumers and businesses and pushing the value of the U.S. dollar higher against foreign currencies. As a result, the benchmark rate rose from a target range of 1.25% to 1.50% at the beginning of the period to the current range of 2.25% to 2.50% at period-end. The fund’s performance fell in line with this rate environment.

What strategies helped the fund to capture more income in the rising-rate market?

Throughout the first half of the period, we maintained a relatively low weighted average maturity [WAM] that was shorter than the fund’s peer group to take advantage of the increasing-rate environment. WAM represents the average life of all the money market securities held in the portfolio. This strategy was advantageous, as yields on three-month Treasury bills rose from 1.38% on December 31, 2017, to 2.36% on December 31, 2018. Yields rose in response to the Fed’s rate increases and the additional supply required by the U.S. Treasury’s need to fund the growing federal deficit. The fund held a high percentage of its assets in overnight repos with highly rated counterparties that were fully collateralized by Treasury and/or government agency or mortgaged-backed securities. This strategy positioned the fund to benefit from the rate increases sooner.

In August, our expectations began to shift from the Fed maintaining a steady pace of rate increases to a view that the Fed may need to extend the period between hikes or even pause as they assess the economic outlook. Consequently, we began increasing our purchases of Treasury bills and agency discount notes in the six-month maturity range. These longer-maturity securities looked more attractive from a valuation perspective and allowed the fund to lock in these rates should the pace of rate increases begin to slow. As a result, the fund’s WAM rose during the course of the reporting period from 19 days on December 31, 2017, to 27 days at period-end, bringing it more in line within its competitive universe.

What are your expectations for Fed policy as 2019 begins?

At the Fed’s December meeting, Chair Jerome Powell mentioned that there were a number of “cross-currents emerging” that warranted a reduction in hikes in 2019 from three to two, which would push thebenchmark rate toward 3.00%. We believe the Fed will continue to weigh various factors, including economic growth, inflationary pressures, and employment. The Fed is also monitoring how changing international developments may affect the domestic economy as it considers the timing and size of future rate increases. Against this backdrop, we will seek to maintain capital preservation, liquidity, and appropriate levels of income by searching for opportunities within the government sector as interest rates trend higher.

Consider these risks before investing:You can lose money by investing in the fund. Although the fund seeks to preserve the value of your investment at $1.00 per share, it cannot guarantee it will do so. An investment in the fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The fund’s sponsor has no legal obligation to provide financial support to the fund, and you should not expect that the sponsor will provide financial support to the fund at any time.

The values of money market investments usually rise and fall in response to changes in interest rates. Interest rate risk is generally lowest for investments with short maturities (a significant part of the fund’s investments). Changes in the financial condition of an issuer or counterparty, changes in specific economic or political conditions that affect a particular type of issuer, and changes in general economic or political conditions can increase the risk of default by an issuer or counterparty, which can affect a security’s or instrument’s credit quality or value. Certain securities in which the fund may invest, including securities issued by certain U.S. government agencies and U.S. government sponsored enterprises, are not guaranteed by the U.S. government or supported by the full faith and credit of the United States. Mortgage-backed investments carry the risk that they may increase in value less when interest rates decline and decline in value more when interest rates rise. We may have to invest the proceeds from prepaid investments, including mortgage- and asset-backed investments, in other investments with less attractive terms and yields.

Your fund’s managers

Portfolio ManagerJoanne M. Driscoll, CFA,joined Putnam in 1995 and has been in the investment industry since 1992.

Portfolio ManagerJonathan M. Topperhas been in the investment industry since he joined Putnam in 1990.

Your fund’s managers also manage other accounts advised by Putnam Management or an affiliate, including retail mutual fund counterparts to the funds in Putnam Variable Trust.

2  Putnam VT Government Money Market Fund 

Understanding your fund’s expenses

As an investor in a variable annuity product that invests in a registered investment company, you pay ongoing expenses, such as management fees, distribution fees (12b-1 fees), and other expenses. Using the following information, you can estimate how these expenses affect your investment and compare them with the expenses of other funds. You may also pay one-time transaction expenses, which are not shown in this section and would result in higher total expenses. Charges and expenses at the insurance company separate account level are not reflected. For more information, see your fund’s prospectus or talk to your financial representative.

Review your fund’s expenses

The two left-hand columns of the Expenses per $1,000 table show the expenses you would have paid on a $1,000 investment in your fund from 7/1/18 to 12/31/18. They also show how much a $1,000 investment would be worth at the close of the period,assuming actual returns and expenses. To estimate the ongoing expenses you paid over the period, divide your account value by $1,000, then multiply the result by the number in the first line for the class of shares you own.

Compare your fund’s expenses with those of other funds

The two right-hand columns of the Expenses per $1,000 table show your fund’s expenses based on a $1,000 investment,assuming a hypothetical 5% annualized return. You can use this information to compare the ongoing expenses (but not transaction expenses or total costs) of investing in the fund with those of other funds. All shareholder reports of mutual funds and funds serving as variable annuity vehicles will provide this information to help you make this comparison. Please note that you cannot use this information to estimate your actual ending account balance and expenses paid during the period.

Expense ratios

	Class IA	Class IB
Total annual operating expenses for the fiscal
year ended 12/31/17	0.45%	0.70%
Annualized expense ratio for the six-month
period ended 12/31/18*	0.45%	0.70%

Fiscal-year expense information in this table is taken from the most recent prospectus, is subject to change, and may differ from that shown for the annualized expense ratio and in the financial highlights of this report.

Expenses are shown as a percentage of average net assets.

*For the fund’s most recent fiscal half year; may differ from expense ratios based on one-year data in the financial highlights.

Expenses per $1,000

			Expenses and value for a
	Expenses and value for a		$1,000 investment, assuming
	$1,000 investment, assuming		a hypothetical 5% annualized
	actual returns for the		return for the 6 months
	6 months ended 12/31/18		ended 12/31/18
	Class IA	Class IB	Class IA	Class IB
Expenses paid
per $1,000*†	$2.28	$3.54	$2.29	$3.57
Ending value
(after
expenses)	$1,008.50	$1,007.20	$1,022.94	$1,021.68

*Expenses for each share class are calculated using the fund’s annualized expense ratio for each class, which represents the ongoing expenses as a percentage of average net assets for the six months ended 12/31/18. The expense ratio may differ for each share class.

†Expenses based on actual returns are calculated by multiplying the expense ratio by the average account value for the period; then multiplying the result by the number of days in the period; and then dividing that result by the number of days in the year. Expenses based on a hypothetical 5% return are calculated by multiplying the expense ratio by the average account value for the six-month period; then multiplying the result by the number of days in the six-month period; and then dividing that result by the number of days in the year.

Putnam VT Government Money Market Fund  3 

Report of Independent Registered Public Accounting Firm

To the Trustees of Putnam Variable Trust
and Shareholders of Putnam VT Government Money Market Fund

Opinion on the Financial Statements

We have audited the accompanying statement of assets and liabilities, including the fund’s portfolio, of Putnam VT Government Money Market Fund (one of the funds constituting Putnam Variable Trust, referred to hereafter as the “Fund”) as of December 31, 2018, the related statement of operations for the year ended December 31, 2018, the statement of changes in net assets for each of the two years in the period ended December 31, 2018, including the related notes, and the financial highlights for each of the five years in the period ended December 31, 2018 (collectively referred to as the “financial statements”). In our opinion, the financial statements present fairly, in all material respects, the financial position of the Fund as of December 31, 2018, the results of its operations for the year then ended, the changes in its net assets for each of the two years in the period ended December 31, 2018 and the financial highlights for each of the five years in the period ended December 31, 2018 in conformity with accounting principles generally accepted in the United States of America.

Basis for Opinion

These financial statements are the responsibility of the Fund’s management. Our responsibility is to express an opinion on the Fund’s financial statements based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) (“PCAOB”) and are required to be independent with respect to the Fund in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits of these financial statements in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud.

Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. Our procedures included confirmation of securities owned as of December 31, 2018 by correspondence with the custodian, transfer agent and brokers; when replies were not received from brokers, we performed other auditing procedures. We believe that our audits provide a reasonable basis for our opinion.

PricewaterhouseCoopers LLP
Boston, Massachusetts
February 12, 2019

We have served as the auditor of one or more investment companies in the Putnam Investments family of mutual funds since at least 1957. We have not been able to determine the specific year we began serving as auditor.

4  Putnam VT Government Money Market Fund 

The fund’s portfolio12/31/18

REPURCHASE AGREEMENTS (67.8%)*	Principal amount	Value
Interest in $378,292,000 joint tri-party
repurchase agreement dated 12/31/18
with Citigroup Global Markets, Inc. due
1/2/19 — maturity value of $19,559,259 for an
effective yield of 3.000% (collateralized by
various mortgage backed securities with
coupon rates ranging from 3.000% to 8.500%
and due dates ranging from 3/15/26 to
12/15/53, valued at $385,881,361)	$19,556,000	$19,556,000
Interest in $450,000,000 joint tri-party
repurchase agreement dated 12/31/18
with HSBC Bank USA, National Association
due 1/2/19 — maturity value of $20,003,333
for an effective yield of 3.000%
(collateralized by a U.S. Treasury note
with a coupon rate of 2.875% and a due
date of 11/15/21, valued at $459,076,568)	20,000,000	20,000,000
Interest in $92,226,000 joint tri-party
repurchase agreement dated 12/31/18
with Merrill Lynch, Pierce, Fenner &
Smith, Inc. due 1/2/19 — maturity value
of $23,686,947 for an effective yield
of 3.000% (collateralized by a mortgage
backed security with a coupon rate of
3.500% and a due date of 3/20/47,
valued at $94,070,521)	23,683,000	23,683,000
Total repurchase agreements (cost $63,239,000)		$63,239,000

U.S. GOVERNMENT AGENCY		Maturity	Principal
OBLIGATIONS (8.0%)*	Yield (%)	date	amount	Value
Federal Farm Credit
Banks Funding
Corporation discount
notes	2.708	11/27/19	$300,000	$292,741
Federal Farm Credit
Banks Funding
Corporation discount
notes	2.670	9/3/19	300,000	294,651
Federal Farm Credit
Banks Funding
Corporation discount
notes	2.635	8/6/19	900,000	885,949
Federal Farm Credit
Banks Funding
Corporation discount
notes	2.614	7/8/19	391,000	385,752
Federal Farm Credit
Banks Funding
Corporation discount
notes	2.555	6/24/19	250,000	246,955
Federal Farm Credit
Banks Funding
Corporation unsec. FRB	2.681	2/25/19	1,000,000	1,000,475
Federal Farm Credit
Banks Funding
Corporation unsec. FRB	2.660	8/19/19	575,000	576,091
Federal Home Loan Banks
unsec. discount notes	2.340	2/15/19	300,000	299,130
Federal Home Loan Banks
unsec. discount notes	2.286	3/8/19	1,000,000	995,857
Federal Home Loan
Mortgage Corporation
unsec. discount notes	2.367	3/20/19	1,000,000	994,930

U.S. GOVERNMENT AGENCY		Maturity	Principal
OBLIGATIONS (8.0%)*cont.	Yield (%)	date	amount	Value
Federal Home Loan
Mortgage Corporation
unsec. FRB	2.406	6/28/19	$1,000,000	$1,000,169
Federal National
Mortgage Association
unsec. FRB	2.387	3/8/19	500,000	500,048
Total u.s. government agency obligations (cost $7,472,748)				$7,472,748

U.S. TREASURY		Maturity	Principal
OBLIGATIONS (25.8%)*	Yield (%)	date	amount	Value
U.S. Treasury Bills	2.585	8/15/19	$900,000	$885,790
U.S. Treasury Bills	2.517	5/23/19	900,000	891,292
U.S. Treasury Bills	2.514	5/9/19	900,000	892,165
U.S. Treasury Bills	2.510	5/16/19	900,000	891,746
U.S. Treasury Bills	2.498	5/2/19	900,000	892,639
U.S. Treasury Bills	2.474	4/25/19	900,000	893,129
U.S. Treasury Bills	2.472	4/18/19	900,000	893,558
U.S. Treasury Bills	2.441	4/11/19	1,000,000	993,393
U.S. Treasury Bills	2.414	4/4/19	1,000,000	993,922
U.S. Treasury Bills	2.408	3/28/19	900,000	894,949
U.S. Treasury Bills	2.376	3/21/19	1,000,000	994,913
U.S. Treasury Bills	2.321	3/14/19	1,000,000	995,475
U.S. Treasury Bills	2.306	3/7/19	1,000,000	995,940
U.S. Treasury Bills	2.279	2/28/19	1,000,000	996,418
U.S. Treasury Bills	2.228	2/21/19	1,000,000	996,921
U.S. Treasury Bills	2.224	2/7/19	1,000,000	997,770
U.S. Treasury Bills	2.221	1/31/19	1,000,000	998,194
U.S. Treasury Bills	2.212	2/14/19	1,000,000	997,362
U.S. Treasury Bills	2.188	1/17/19	1,000,000	999,050
U.S. Treasury Bills	2.177	1/10/19	1,000,000	999,468
U.S. Treasury Bills	2.176	1/24/19	1,000,000	998,644
U.S. Treasury Bills	2.171	1/3/19	1,000,000	999,882
U.S. Treasury FRN	2.570	1/31/19	1,000,000	1,000,008
U.S. Treasury FRN	2.473	7/31/20	1,000,000	1,000,047
U.S. Treasury FRN	2.463	4/30/20	1,000,000	1,000,040
Total U.S. treasury obligations (cost $24,092,715)			$24,092,715
Total investments (cost $94,804,463)			$94,804,463

Key to holding’s abbreviations

FRB	Floating Rate Bonds: the rate shown is the current interest rate at the
	close of the reporting period. Rates may be subject to a cap or floor.
	For certain securities, the rate may represent a fixed rate currently in
	place at the close of the reporting period.
FRN	Floating Rate Notes: the rate shown is the current interest rate or
	yield at the close of the reporting period. Rates may be subject to a
	cap or floor. For certain securities, the rate may represent a fixed rate
	currently in place at the close of the reporting period.

Notes to the fund’s portfolio

Unless noted otherwise, the notes to the fund’s portfolio are for the close of the fund’s reporting period, which ran from January 1, 2018 through December 31, 2018 (the reporting period). Within the following notes to the portfolio, references to “Putnam Management” represent Putnam Investment Management, LLC, the fund’s manager, an indirect wholly-owned subsidiary of Putnam Investments, LLC and references to “ASC 820” represent Accounting Standards Codification 820Fair Value Measurements and Disclosures.

* Percentages indicated are based on net assets of $93,307,216.

The dates shown on debt obligations are the original maturity dates.

Putnam VT Government Money Market Fund  5 

ASC 820 establishes a three-level hierarchy for disclosure of fair value measurements. The valuation hierarchy is based upon the transparency of inputs to the valuation of the fund’s investments. The three levels are defined as follows:

Level 1: Valuations based on quoted prices for identical securities in active markets.

Level 2: Valuations based on quoted prices in markets that are not active or for which all significant inputs are observable, either directly or indirectly.

Level 3: Valuations based on inputs that are unobservable and significant to the fair value measurement.

The following is a summary of the inputs used to value the fund’s net assets as of the close of the reporting period:

			Valuation inputs
Investments in securities:	Level 1	Level 2		Level 3
Repurchase agreements	$—­	$63,239,000		$—­
U.S. government agency obligations	—­	7,472,748		—­
U.S. treasury obligations	—­	24,092,715		—­
Totals by level	$—­	$94,804,463		$—­

The accompanying notes are an integral part of these financial statements.

6  Putnam VT Government Money Market Fund 

Statement of assets and liabilities
12/31/18

Assets
Investment in securities, at value (Note 1):
Unaffiliated issuers (identified cost $31,565,463)	$31,565,463
Repurchase agreements (identified cost $63,239,000)	63,239,000
Cash	13,125
Interest and other receivables	65,106
Receivable for shares of the fund sold	256,357
Total assets	95,139,051
Liabilities
Payable for shares of the fund repurchased	1,638,082
Payable for compensation of Manager (Note 2)	22,357
Payable for custodian fees (Note 2)	5,061
Payable for investor servicing fees (Note 2)	10,764
Payable for Trustee compensation and expenses (Note 2)	93,503
Payable for administrative services (Note 2)	1,000
Payable for distribution fees (Note 2)	9,713
Other accrued expenses	51,355
Total liabilities	1,831,835
Net assets	$93,307,216
Represented by
Paid-in capital (Unlimited shares authorized) (Notes 1 and 4)	$93,309,633
Total distributable earnings (Note 1)	(2,417)
Total — Representing net assets applicable to capital shares outstanding	$93,307,216
Computation of net asset value Class IA
Net assets	$48,473,407
Number of shares outstanding	48,474,421
Net asset value, offering price and redemption price per share (net assets divided by number of shares outstanding)	$1.00
Computation of net asset value Class IB
Net assets	$44,833,809
Number of shares outstanding	44,835,199
Net asset value, offering price and redemption price per share (net assets divided by number of shares outstanding)	$1.00

The accompanying notes are an integral part of these financial statements.

Putnam VT Government Money Market Fund  7 

Statement of operations
Year ended 12/31/18

Investment income
Interest	$1,764,204
Total investment income	1,764,204
Expenses
Compensation of Manager (Note 2)	266,998
Investor servicing fees (Note 2)	66,330
Custodian fees (Note 2)	9,184
Trustee compensation and expenses (Note 2)	4,439
Distribution fees (Note 2)	117,103
Administrative services (Note 2)	2,735
Auditing and tax fees	38,855
Other	35,488
Total expenses	541,132
Expense reduction (Note 2)	(247)
Net expenses	540,885
Net investment income	1,223,319
Net increase in net assets resulting from operations	$1,223,319

Statement of changes in net assets

	Year ended	Year ended
	12/31/18	12/31/17
Decrease in net assets
Operations:
Net investment income	$1,223,319	$367,663
Net increase in net assets resulting from operations	1,223,319	367,663
Distributions to shareholders (Note 1):
From ordinary income
Net investment income
Class IA	(677,635)	(241,634)
Class IB	(546,559)	(124,293)
Decrease from capital share transactions (Note 4)	(6,064,124)	(10,667,864)
Total decrease in net assets	(6,064,999)	(10,666,128)
Net assets:
Beginning of year	99,372,215	110,038,343
End of year(Note 1)	$93,307,216	$99,372,215

The accompanying notes are an integral part of these financial statements.

8  Putnam VT Government Money Market Fund 

Financial highlights(For a common share outstanding throughout the period)

LESS

RATIOS AND

INVESTMENT OPERATIONS:

DISTRIBUTIONS:

SUPPLEMENTAL DATA:

Period ended

Net asset value, beginning of period

Net investment income (loss)

Net realized gain (loss) on investments

Total from investment operations

From net investment income

Total distributions

Non-recurring payment

Net asset value, end of period

Total return at net asset value (%)a,b

Net assets, end of period (in thousands)

Ratio of expenses to average net assets (%)a,c

Ratio of net investment income (loss) to average net   assets (%)

Class IA­

12/31/18­

$1.00­

.0142­

—­

.0142­

(.0142)

(.0142)

—­

$1.00­

1.43­

$48,473­

.45­

1.41­

12/31/17­

1.00­

.0047­

—­

.0047­

(.0047)

(.0047)

—­

1.00­

.47­

50,212­

.45d

.46d

12/31/16­

1.00­

.0001­

(.0001)

—e

(.0001)

(.0001)

—­

1.00­

.01­

55,915­

.37d

.01d

12/31/15­

1.00­

.0001­

—e

.0001­

(.0001)

(.0001)

—­

1.00­

.01­

64,790­

.19d

.01d

12/31/14­

1.00­

.0001­

—­

.0001­

(.0001)

(.0001)

.0017f

1.00­

.01­

75,352­

.13d

.01d

Class IB­

12/31/18­

$1.00­

.0117­

—­

.0117­

(.0117)

(.0117)

—­

$1.00­

1.18­

$44,834­

.70­

1.17­

12/31/17­

1.00­

.0025­

—­

.0025­

(.0024)

(.0024)

—­

1.00­

.24­

49,160­

.67d

.24d

12/31/16­

1.00­

.0001­

(.0001)

—e

(.0001)

(.0001)

—­

1.00­

.01­

54,124­

.38d

.01d

12/31/15­

1.00­

.0001­

—e

.0001­

(.0001)

(.0001)

—­

1.00­

.01­

63,632­

.19d

.01d

12/31/14­

1.00­

.0001­

—­

.0001­

(.0001)

(.0001)

.0016f

1.00­

.01­

78,635­

.13d

.01d

^aThe charges and expenses at the insurance company separate account level are not reflected.

^bTotal return assumes dividend reinvestment.

^cIncludes amounts paid through expense offset arrangements, if any (Note 2). Also excludes acquired fund fees and expenses, if any.

^dReflects a voluntary waiver of certain fund expenses in effect during the period relating to the enhancement of certain annualized net yields of the fund. As a result of such waivers, the expenses of each class reflect a reduction of the following amounts as a percentage of average net assets (Note 2):

	12/31/17	12/31/16	12/31/15	12/31/14
Class IA	N/A	0.08%	0.24%	0.32%
Class IB	0.03%	0.32	0.49	0.57

^eAmount represents less than $0.0001 per share.

^fReflects a voluntary non-recurring payment from Putnam Investments.

The accompanying notes are an integral part of these financial statements.

Putnam VT Government Money Market Fund  9 

Notes to financial statements12/31/18

Within the following Notes to financial statements, references to “State Street” represent State Street Bank and Trust Company, references to “the SEC” represent the Securities and Exchange Commission, references to “Putnam Management” represent Putnam Investment Management, LLC, the fund’s manager, an indirect wholly-owned subsidiary of Putnam Investments, LLC and references to “OTC”, if any, represent over-the-counter. Unless otherwise noted, the “reporting period” represents the period from January 1, 2018 through December 31, 2018.

Putnam VT Government Money Market Fund (the fund) is a diversified series of Putnam Variable Trust (the Trust), a Massachusetts business trust registered under the Investment Company Act of 1940, as amended, as an open-end management investment company. The goal of the fund is to seek as high a rate of current income as Putnam Management believes is consistent with preservation of capital and maintenance of liquidity. The fund invests at least 99.5 percent of the fund’s total assets in cash, U.S. government securities and repurchase agreements that are fully collateralized by U.S. government securities or cash. The fund invests mainly in debt securities that are obligations of the U.S. government, its agencies and instrumentalities and accordingly are backed by the full faith and credit of the United States (e.g., U.S. Treasury bills) or by the credit of a federal agency or government-sponsored entity (e.g., securities issued by Fannie Mae and Freddie Mac). The U.S. government securities in which the fund invests may also include variable and floating rate instruments and when-issued and delayed delivery securities (i.e., payment or delivery of the securities occurs at a future date for a predetermined price). Under normal circumstances, the fund invests at least 80% of the fund’s net assets in U.S. government securities and repurchase agreements that are fully collateralized by U.S. government securities. This policy may be changed only after 60 days’ notice to shareholders. The securities purchased by the fund are subject to quality, maturity, diversification and other requirements pursuant to rules promulgated by the SEC. Putnam Management may consider, among other factors, credit and interest rate risks, as well as general market conditions, when deciding whether to buy or sell investments.

The fund offers class IA and class IB shares of beneficial interest. Class IA shares are offered at net asset value and are not subject to a distribution fee. Class  IB shares are offered at net asset value and pay an ongoing distribution fee, which is identified in Note 2.

In the normal course of business, the fund enters into contracts that may include agreements to indemnify another party under given circumstances. The fund’s maximum exposure under these arrangements is unknown as this would involve future claims that may be, but have not yet been, made against the fund. However, the fund’s management team expects the risk of material loss to be remote.

The fund has entered into contractual arrangements with an investment adviser, administrator, distributor, shareholder servicing agent and custodian, who each provide services to the fund. Unless expressly stated otherwise, shareholders are not parties to, or intended beneficiaries of these contractual arrangements, and these contractual arrangements are not intended to create any shareholder right to enforce them against the service providers or to seek any remedy under them against the service providers, either directly or on behalf of the fund.

Under the fund’s Amended and Restated Agreement and Declaration of Trust, any claims asserted against or on behalf of the Putnam Funds, including claims against Trustees and Officers, must be brought in state and federal courts located within the Commonwealth of Massachusetts.

Note 1 — Significant accounting policies

The following is a summary of significant accounting policies consistently followed by the fund in the preparation of its financial statements. The preparation of financial statements is in conformity with accounting principles generally accepted in the United States of America and requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities in the financial statements and the reported amounts of increases and decreases in net assets from operations. Actual results could differ from those estimates. Subsequent events after the Statement of assets and liabilities date through the date that the financial statements were issued have been evaluated in the preparation of the financial statements.

Investment income, realized gains and losses and expenses of the fund are borne pro-rata based on the relative net assets of each class to the total net assets of the fund, except that each class bears expenses unique to that class (including the distribution fees applicable to such classes). Each class votes as a class only with respect to its own distribution plan or other matters on which a class vote is required by law or determined by the Trustees. Shares of each class would receivetheir pro-rata share of the net assets of the fund, if the fund were liquidated. In addition, the Trustees declare separate dividends on each class of shares.

Security valuationPortfolio securities and other investments are valued using policies and procedures adopted by the Board of Trustees. The Trustees have formed a Pricing Committee to oversee the implementation of these procedures and have delegated responsibility for valuing the fund’s assets in accordance with these procedures to Putnam Management. Putnam Management has established an internal Valuation Committee that is responsible for making fair value determinations, evaluating the effectiveness of the pricing policies of the fund and reporting to the Pricing Committee.

The valuation of the fund’s portfolio instruments is determined by means of the amortized cost method (which approximates fair value) as set forth in Rule 2a–7 under the Investment Company Act of 1940. The amortized cost of an instrument is determined by valuing it at its original cost and thereafter amortizing any discount or premium from its face value at a constant rate until maturity and is generally categorized as a Level 2 security.

Joint trading accountPursuant to an exemptive order from the SEC, the fund may transfer uninvested cash balances into a joint trading account along with the cash of other registered investment companies and certain other accounts managed by Putnam Management. These balances may be invested in issues of short-term investments having maturities of up to 90 days.

Repurchase agreementsThe fund, or any joint trading account, through its custodian, receives delivery of the underlying securities, the fair value of which at the time of purchase is required to be in an amount at least equal to the resale price, including accrued interest. Collateral for certain tri-party repurchase agreements, which totaled $64,508,399, is held at the counterparty’s custodian in a segregated account for the benefit of the fund and the counterparty. Putnam Management is responsible for determining that the value of these underlying securities is at all times at least equal to the resale price, including accrued interest. In the event of default or bankruptcy by the other party to the agreement, retention of the collateral may be subject to legal proceedings.

Security transactions and related investment incomeSecurity transactions are recorded on the trade date (the date the order to buy or sell is executed). Interest income is recorded on the accrual basis. Premiums and discounts from purchases of short-term investments are amortized/accreted at a constant rate until maturity. Gains or losses on securities sold are determined on the identified cost basis.

Interfund lendingThe fund, along with other Putnam funds, may participate in an interfund lending program pursuant to an exemptive order issued by the SEC. This program allows the fund to lend to other Putnam funds that permit such transactions. Interfund lending transactions are subject to each fund’s investment policies and borrowing and lending limits. Interest earned or paid on the interfund lending transaction will be based on the average of certain current market rates. During the reporting period, the fund did not utilize the program.

Lines of creditThe fund participates, along with other Putnam funds, in a $317.5 million unsecured committed line of credit and a $235.5 million unsecured uncommitted line of credit, both provided by State Street. Borrowings may be made for temporary or emergency purposes, including the funding of shareholder redemption requests and trade settlements. Interest is charged to the fund based on the fund’s borrowing at a rate equal to 1.25% plus the higher of (1) the Federal Funds rate and (2) the overnight LIBOR for the committed line of credit and the Federal Funds rate plus 1.30% for the uncommitted line of credit. A closing fee equal to 0.04% of the committed line of credit and 0.04% of the uncommitted line of credit has been paid by the participating funds. In addition, a commitment fee of 0.21% per annum on any unutilized portion of the committed line of credit is allocated to the participating funds based on their relative net assets and paid quarterly. During the reporting period, the fund had no borrowings against these arrangements.

Federal taxesIt is the policy of the fund to distribute all of its taxable income within the prescribed time period and otherwise comply with the provisions of the Internal Revenue Code of 1986, as amended (the Code), applicable to regulated investment companies.

The fund is subject to the provisions of Accounting Standards Codification 740Income Taxes(ASC 740). ASC 740 sets forth a minimum threshold for financial statement recognition of the benefit of a tax position taken or expected to be taken in a tax return. The fund did not have a liability to record for any unrecognized tax benefits in the accompanying financial statements. No provision has been made

10  Putnam VT Government Money Market Fund 

for federal taxes on income, capital gains or unrealized appreciation on securities held nor for excise tax on income and capital gains. Each of the fund’s federal tax returns for the prior three fiscal years remains subject to examination by the Internal Revenue Service.

Under the Regulated Investment Company Modernization Act of 2010, the fund will be permitted to carry forward capital losses incurred for an unlimited period and the carry forwards will retain their character as either short-term or long-term capital losses. At December 31, 2018, the fund had the following capital loss carryovers available, to the extent allowed by the Code, to offset future net capital gain, if any:

	Loss carryover
Short-term	Long-term	Total
$—	$3,278	$3,278

Distributions to shareholdersIncome dividends are recorded daily by the fund and are paid monthly. Distributions from capital gains, if any, are paid at least annually. The amount and character of income and gains to be distributed are determined in accordance with income tax regulations, which may differ from generally accepted accounting principles. For the reporting period, there were no material temporary or permanent differences. Reclassifications are made to the fund’s capital accounts to reflect income and gains available for distribution (or available capital loss carryovers) under income tax regulations. At the close of the reporting period, the fund required no such reclassifications.

The tax basis components of distributable earnings as of the close of the reporting period were as follows:

Undistributed ordinary income	$1,192
Capital loss carryforward	(3,278)
Cost for federal income tax purposes	$94,804,463

The aggregate identified cost on a financial reporting and tax basis is the same.

For the fiscal year ended December 31, 2017, the fund had undistributed net investment income of $1,736.

Expenses of the TrustExpenses directly charged or attributable to any fund will be paid from the assets of that fund. Generally, expenses of the Trust will be allocated among and charged to the assets of each fund on a basis that the Trustees deem fair and equitable, which may be based on the relative assets of each fund or the nature of the services performed and relative applicability to each fund.

Beneficial interestAt the close of the reporting period, insurance companies or their separate accounts were record owners of all but a de minimis number of the shares of the fund. Approximately 34.8% of the fund is owned by accounts of one insurance company.

Note 2 — Management fee, administrative services and other transactions

The fund pays Putnam Management a management fee (based on the fund’s average net assets and computed and paid monthly) at annual rates that may vary based on the average of the aggregate net assets of all open-end mutual funds sponsored by Putnam Management (excluding net assets of funds that are invested in, or that are invested in by, other Putnam funds to the extent necessary to avoid “double counting” of those assets). Such annual rates may vary as follows:

0.440%	of the first $5 billion,
0.390%	of the next $5 billion,
0.340%	of the next $10 billion,
0.290%	of the next $10 billion,
0.240%	of the next $50 billion,
0.220%	of the next $50 billion,
0.210%	of the next $100 billion and
0.205%	of any excess thereafter.

For the reporting period, the management fee represented an effective rate (excluding the impact from any expense waivers in effect) of 0.282% of the fund’s average net assets.

Putnam Management has contractually agreed, through April 30, 2020, to waive fees and/or reimburse the fund’s expenses to the extent necessary to limit the cumulative expenses of the fund, exclusive of brokerage, interest, taxes, investment-related expenses, extraordinary expenses, acquired fund fees and expenses and payments under the fund’s investor servicing contract, investment management contract and distribution plan, on a fiscal year-to-date basis to an annual rate of 0.20% of the fund’s average net assets over such fiscal year-to-dateperiod. During the reporting period, the fund’s expenses were not reduced as a result of this limit.

Putnam Investments Limited (PIL), an affiliate of Putnam Management, is authorized by the Trustees to manage a separate portion of the assets of the fund as determined by Putnam Management from time to time. PIL did not manage any portion of the assets of the fund during the reporting period. If Putnam Management were to engage the services of PIL, Putnam Management would pay a quarterly sub-management fee to PIL for its services at an annual rate of 0.25% of the average net assets of the portion of the fund managed by PIL.

The fund reimburses Putnam Management an allocated amount for the compensation and related expenses of certain officers of the fund and their staff who provide administrative services to the fund. The aggregate amount of all such reimbursements is determined annually by the Trustees.

Custodial functions for the fund’s assets are provided by State Street. Custody fees are based on the fund’s asset level, the number of its security holdings and transaction volumes.

Putnam Investor Services, Inc., an affiliate of Putnam Management, provides investor servicing agent functions to the fund. Putnam Investor Services, Inc. was paid a monthly fee for investor servicing at an annual rate of 0.07% of the fund’s average daily net assets. During the reporting period, the expenses for each class of shares related to investor servicing fees were as follows:

Class IA	$33,537
Class IB	32,793
Total	$66,330

The fund has entered into expense offset arrangements with Putnam Investor Services, Inc. and State Street whereby Putnam Investor Services, Inc.’s and State Street’s fees are reduced by credits allowed on cash balances. For the reporting period, the fund’s expenses were reduced by $247 under the expense offset arrangements.

Each Independent Trustee of the fund receives an annual Trustee fee, of which $64, as a quarterly retainer, has been allocated to the fund, and an additional fee for each Trustees meeting attended. Trustees also are reimbursed for expenses they incur relating to their services as Trustees.

The fund has adopted a Trustee Fee Deferral Plan (the Deferral Plan) which allows the Trustees to defer the receipt of all or a portion of Trustees fees payable on or after July 1, 1995. The deferred fees remain invested in certain Putnam funds until distribution in accordance with the Deferral Plan.

The fund has adopted an unfunded noncontributory defined benefit pension plan (the Pension Plan) covering all Trustees of the fund who have served as a Trustee for at least five years and were first elected prior to 2004. Benefits under the Pension Plan are equal to 50% of the Trustee’s average annual attendance and retainer fees for the three years ended December 31, 2005. The retirement benefit is payable during a Trustee’s lifetime, beginning the year following retirement, for the number of years of service through December 31, 2006. Pension expense for the fund is included in Trustee compensation and expenses in the Statement of operations. Accrued pension liability is included in Payable for Trustee compensation and expenses in the Statement of assets and liabilities. The Trustees have terminated the Pension Plan with respect to any Trustee first elected after 2003.

The fund has adopted a distribution plan (the Plan) with respect to its class  IB shares pursuant to Rule 12b–1 under the Investment Company Act of 1940. The purpose of the Plan is to compensate Putnam Retail Management Limited Partnership, an indirect wholly-owned subsidiary of Putnam Investments, LLC, for services provided and expenses incurred in distributing shares of the fund. The Plan provides for payment by the fund to Putnam Retail Management Limited Partnership at an annual rate of up to 0.35% of the average net assets attributable to the fund’s class IB shares. The Trustees have approved payment by the fund at an annual rate of 0.25% of the average net assets attributable to the fund’s class IB shares. The expenses related to distribution fees during the reporting period are included in Distribution fees in the Statement of operations.

Note 3 — Purchases and sales of securities

During the reporting period, the cost of purchases and the proceeds from sales (including maturities) of investment securities (all short-term obligations) aggregated $17,335,577,766 and $17,340,572,000, respectively. The fund may purchase or sell investments from or to other Putnam funds in the ordinary course of business, which can reduce the fund’s transaction costs, at prices determined in accordance with SEC requirements and policies approved by the Trustees. During the reporting period, purchases or sales from or to other Putnam funds, if any, did not represent more than 5% of the fund’s total cost of purchases and/or total proceeds from sales.

Putnam VT Government Money Market Fund  11 

Note 4 — Capital shares

At the close of the reporting period, there were an unlimited number of shares of beneficial interest authorized. Subscriptions and redemptions are presented at the omnibus level. Transactions in capital shares were as follows:

		Class IA shares				Class IB shares
	Year ended 12/31/18		Year ended 12/31/17		Year ended 12/31/18		Year ended 12/31/17
	Shares	Amount	Shares	Amount	Shares	Amount	Shares	Amount
Shares sold	24,174,459	$24,174,459	19,228,099	$19,228,099	11,498,242	$11,498,242	10,662,798	$10,662,798
Shares issued in connection with
reinvestment of distributions	677,635	677,635	241,723	241,723	546,559	546,559	124,432	124,432
	24,852,094	24,852,094	19,469,822	19,469,822	12,044,801	12,044,801	10,787,230	10,787,230
Shares repurchased	(26,590,539)	(26,590,539)	(25,173,271)	(25,173,271)	(16,370,480)	(16,370,480)	(15,751,645)	(15,751,645)
Net decrease	(1,738,445)	$(1,738,445)	(5,703,449)	$(5,703,449)	(4,325,679)	$(4,325,679)	(4,964,415)	$(4,964,415)

Note 5 — Market, credit and other risks

In the normal course of business, the fund trades financial instruments and enters into financial transactions where risk of potential loss exists due to changes in the market (market risk) or failure of the contracting party to the transaction to perform (credit risk). The fund may be exposed to additional credit risk that an institution or other entity with which the fund has unsettled or open transactions will default.

Note 6 — Offsetting of financial and derivative assets and liabilities

The following table summarizes any derivatives, repurchase agreements and reverse repurchase agreements, at the end of the reporting period, that are subject to an enforceable master netting agreement or similar agreement. For securities lending transactions or borrowing transactions associated with securities sold short, if any, see Note 1. For financial reporting purposes, the fund does not offset financial assets and financial liabilities that are subject to the master netting agreements in the Statement of assets and liabilities.

	Citigroup Global	HSBC Bank USA,	Merrill Lynch, Pierce,
	Markets, Inc.	National Association	Fenner & Smith, Inc.	Total
Assets:
Repurchase agreements**	$19,556,000	$20,000,000	$23,683,000	$63,239,000
Total Assets	$19,556,000	$20,000,000	$23,683,000	$63,239,000
Total Financial and Derivative Net Assets	$19,556,000	$20,000,000	$23,683,000	$63,239,000
Total collateral received (pledged)†##	$19,556,000	$20,000,000	$23,683,000
Net amount	$—	$—	$—
Controlled collateral received (including
TBA commitments)**	$—	$—	$—	$—
Uncontrolled collateral received	$19,948,336	$20,403,403	$24,156,660	$64,508,399
Collateral (pledged) (including
TBA commitments)**	$—	$—	$—	$—

** Included with Investments in securities on the Statement of assets and liabilities.

† Additional collateral may be required from certain brokers based on individual agreements.

^##Any over-collateralization of total financial and derivative net assets is not shown. Collateral may include amounts related to unsettled agreements.

12  Putnam VT Government Money Market Fund 

Putnam VT Government Money Market Fund   13 

*Mr. Reynolds is an “interested person” (as defined in the Investment Company Act of 1940) of the fund and Putnam Investments. He is President and Chief Executive Officer of Putnam Investments, as well as the President of your fund and each of the other Putnam funds.

The address of each Trustee is 100 Federal Street, Boston, MA 02110.

As of December 31, 2018, there were 99 Putnam funds. All Trustees serve as Trustees of all Putnam funds.

Each Trustee serves for an indefinite term, until his or her resignation, retirement at age 75, removal, or death.

Officers

In addition to Robert L. Reynolds, the other officers of the fund are shown below:

Jonathan S. Horwitz(Born 1955)	Michael J. Higgins(Born 1976)	Mark C. Trenchard(Born 1962)
Executive Vice President, Principal Executive	Vice President, Treasurer, and Clerk	Vice President and BSA Compliance Officer
Officer, and Compliance Liaison	Since 2010	Since 2002
Since 2004		Director of Operational Compliance,
	Janet C. Smith(Born 1965)	Putnam Investments and Putnam
Robert T. Burns(Born 1961)	Vice President, Principal Financial Officer,	Retail Management
Vice President and Chief Legal Officer	Principal Accounting Officer, and Assistant
Since 2011	Treasurer	Nancy E. Florek(Born 1957)
General Counsel, Putnam Investments, Putnam	Since 2007	Vice President, Director of Proxy Voting and
Management, and Putnam Retail Management	Head of Fund Administration Services,	Corporate Governance, Assistant Clerk, and
	Putnam Investments and Putnam Management	Assistant Treasurer
James F. Clark(Born 1974)		Since 2000
Vice President and Chief Compliance Officer	Susan G. Malloy(Born 1957)
Since 2016	Vice President and Assistant Treasurer	Denere P. Poulack(Born 1968)
Chief Compliance Officer, Putnam Investments	Since 2007	Assistant Vice President, Assistant Clerk,
and Putnam Management	Head of Accounting, Middle Office, & Control	and Assistant Treasurer
	Services, Putnam Investments and	Since 2004
	Putnam Management

The principal occupations of the officers for the past five years have been with the employers as shown above, although in some cases they have held different positions with such employers. The address of each officer is 100 Federal Street, Boston, MA 02110.

14  Putnam VT Government Money Market Fund 

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Putnam VT Government Money Market Fund  15 

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16  Putnam VT Government Money Market Fund 

Other important information

Proxy voting

Putnam is committed to managing our mutual funds in the best interests of our shareholders. The Putnam funds’ proxy voting guidelines and procedures, as well as information regarding how your fund voted proxies relating to portfolio securities during the 12-month period ended June 30, 2018, are available in the Individual Investors section of putnam.com and on the Securities and Exchange Commission’s (SEC) website, www.sec.gov. If you have questions about finding forms on the SEC’s website, you may call the SEC at 1-800-SEC-0330. You may also obtain the Putnam funds’ proxy voting guidelines and procedures at no charge by calling Putnam’s Shareholder Services at 1-800-225-1581.

Fund portfolio holdings

Each Putnam VT fund will file a complete schedule of its portfolio holdings with the SEC for the first and third quarters of each fiscal year on Form N-Q.Shareholders may obtain the fund’s Form N-Q on the SEC’s website at www.sec.gov.

Fund information

Investment Manager	Investor Servicing Agent	Trustees
Putnam Investment Management, LLC	Putnam Investments	Kenneth R. Leibler, Chair
100 Federal Street	Mailing address:	Liaquat Ahamed
Boston, MA 02110	P.O. Box 219697	Ravi Akhoury
	Kansas City, MO 64121-9697	Barbara M. Baumann
Investment Sub-Advisor	1-800-225-1581	Katinka Domotorffy
Putnam Investments Limited		Catharine Bond Hill
16 St James’s Street	Custodian	Paul L. Joskow
London, England SW1A 1ER	State Street Bank and Trust Company	Robert E. Patterson
		George Putnam, III
Marketing Services	Legal Counsel	Robert L. Reynolds
Putnam Retail Management	Ropes & Gray LLP	Manoj P. Singh
100 Federal Street
Boston, MA 02110	Independent Registered
	Public Accounting Firm
	PricewaterhouseCoopers LLP

The fund’s Statement of Additional Information contains additional information about the fund’s Trustees and is available without charge upon request by calling 1-800-225-1581.

Putnam VT Government Money Market Fund   17 

This report has been prepared for the shareholders	H517
of Putnam VT Government Money Market Fund.	VTAN039 315003 2/19

Item 2. Code of Ethics:

(a) The fund’s principal executive, financial and accounting officers are employees of Putnam Investment Management, LLC, the Fund’s investment manager. As such they are subject to a comprehensive Code of Ethics adopted and administered by Putnam Investments which is designed to protect the interests of the firm and its clients. The Fund has adopted a Code of Ethics which incorporates the Code of Ethics of Putnam Investments with respect to all of its officers and Trustees who are employees of Putnam Investment Management, LLC. For this reason, the Fund has not adopted a separate code of ethics governing its principal executive, financial and accounting officers.

(c) In February 2018, the Code of Ethics of Putnam Investments was amended. The key changes to the Code of Ethics are as follows: (i) Prohibition of investing in public coin offerings or token offerings, (ii) Removal of monetary fines as available sanctions for violations of the Code of Ethics, and (iii) Expanded definition of “Immediate Family Member”.

Item 3. Audit Committee Financial Expert:

The Funds’ Audit, Compliance and Distributions Committee is comprised solely of Trustees who are “independent” (as such term has been defined by the Securities and Exchange Commission (“SEC”) in regulations implementing Section 407 of the Sarbanes-Oxley Act (the “Regulations”)). The Trustees believe that each of the members of the Audit, Compliance and Distributions Committee also possess a combination of knowledge and experience with respect to financial accounting matters, as well as other attributes, that qualify them for service on the Committee. In addition, the Trustees have determined that each of Mr. Patterson, Ms. Baumann and Mr. Singh qualifies as an “audit committee financial expert” (as such term has been defined by the Regulations) based on their review of his or her pertinent experience and education. The SEC has stated, and the funds’ amended and restated agreement and Declaration of Trust provides, that the designation or identification of a person as an audit committee financial expert pursuant to this Item 3 of Form N-CSR does not impose on such person any duties, obligations or liability that are greater than the duties, obligations and liability imposed on such person as a member of the Audit, Compliance and Distribution Committee and the Board of Trustees in the absence of such designation or identification.

Item 4. Principal Accountant Fees and Services:

The following table presents fees billed in each of the last two fiscal years for services rendered to the fund by the fund’s independent auditor:

Fiscal year ended	Audit Fees	Audit-Related Fees	Tax Fees	All Other Fees
December 31, 2018	$35,533	$ —	$3,272	$ —
December 31, 2017	$38,082	$ —	$3,272	$135

For the fiscal years ended December 31, 2018 and December 31, 2017, the fund’s independent auditor billed aggregate non-audit fees in the amounts of $619,754 and $385,937 respectively, to the fund, Putnam Management and any entity controlling, controlled by or under common control with Putnam Management that provides ongoing services to the fund.

Audit Fees represent fees billed for the fund’s last two fiscal years relating to the audit and review of the financial statements included in annual reports and registration statements, and other services that are normally provided in connection with statutory and regulatory filings or engagements.

Audit-Related Fees represent fees billed in the fund’s last two fiscal years for services traditionally performed by the fund’s auditor, including accounting consultation for proposed transactions or concerning financial accounting and reporting standards and other audit or attest services not required by statute or regulation.

Tax Fees represent fees billed in the fund’s last two fiscal years for tax compliance, tax planning and tax advice services. Tax planning and tax advice services include assistance with tax audits, employee benefit plans and requests for rulings or technical advice from taxing authorities.

All Other Fees represent fees billed for services relating to an analysis of fund profitability

Pre-Approval Policies of the Audit, Compliance and Distributions Committee. The Audit, Compliance and Distributions Committee of the Putnam funds has determined that, as a matter of policy, all work performed for the funds by the funds’ independent auditors will be pre-approved by the Committee itself and thus will generally not be subject to pre-approval procedures.

The Audit, Compliance and Distributions Committee also has adopted a policy to pre-approve the engagement by Putnam Management and certain of its affiliates of the funds’ independent auditors, even in circumstances where pre-approval is not required by applicable law. Any such requests by Putnam Management or certain of its affiliates are typically submitted in writing to the Committee and explain, among other things, the nature of the proposed engagement, the estimated fees, and why this work should be performed by that particular audit firm as opposed to another one. In reviewing such requests, the Committee considers, among other things, whether the provision of such services by the audit firm are compatible with the independence of the audit firm.

The following table presents fees billed by the fund’s independent auditor for services required to be approved pursuant to paragraph (c)(7)(ii) of Rule 2-01 of Regulation S-X.

Fiscal year ended	Audit-Related Fees	Tax Fees	All Other Fees	Total Non-Audit Fees
December 31, 2018	$ —	$616,482	$ —	$ —
December 31, 2017	$ —	$382,530	$ —	$ —

Item 5. Audit Committee of Listed Registrants

Not applicable

Item 6. Schedule of Investments:

The registrant’s schedule of investments in unaffiliated issuers is included in the report to shareholders in Item 1 above.

Item 7. Disclosure of Proxy Voting Policies and Procedures For Closed-End Management Investment Companies:

Not applicable

Item 8. Portfolio Managers of Closed-End Investment Companies

Not Applicable

Item 9. Purchases of Equity Securities by Closed-End Management Investment Companies and Affiliated Purchasers:

Not applicable

Item 10. Submission of Matters to a Vote of Security Holders:

Not applicable

Item 11. Controls and Procedures:

(a) The registrant’s principal executive officer and principal financial officer have concluded, based on their evaluation of the effectiveness of the design and operation of the registrant’s disclosure controls and procedures as of a date within 90 days of the filing date of this report, that the design and operation of such procedures are generally effective to provide reasonable assurance that information required to be disclosed by the registrant in this report is recorded, processed, summarized and reported within the time periods specified in the Commission’s rules and forms.

(b) Changes in internal control over financial reporting: Not applicable

Item 12. Exhibits:

(a)(1) The Code of Ethics of The Putnam Funds, which incorporates the Code of Ethics of Putnam Investments, is filed herewith.

(a)(2) Separate certifications for the principal executive officer and principal financial officer of the registrant as required by Rule 30a-2(a) under the Investment Company Act of 1940, as amended, are filed herewith.

(b) The certifications required by Rule 30a-2(b) under the Investment Company Act of 1940, as amended, are filed herewith.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

Putnam Variable Trust

By (Signature and Title):

/s/ Janet C. Smith
Janet C. Smith
Principal Accounting Officer

Date: February 28, 2019

Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, this report has been signed below by the following persons on behalf of the registrant and in the capacities and on the dates indicated.

By (Signature and Title):

/s/ Jonathan S. Horwitz
Jonathan S. Horwitz
Principal Executive Officer

Date: February 28, 2019

By (Signature and Title):

/s/ Janet C. Smith
Janet C. Smith
Principal Financial Officer

Date: February 28, 2019