Hartford Series Fund N-CSRCertified annual shareholder report (management investment company)

Average Annual Total Returns

for the Periods Ending 12/31/2020

PERFORMANCE DATA QUOTED REPRESENTS PAST PERFORMANCE AND DOES NOT GUARANTEE FUTURE RESULTS. The investment return and principal value of the investment will fluctuate so that investors’ shares, when redeemed, may be worth more or less than their original cost. The table and chart do not reflect the deductions of taxes, sales charges or other fees which may be applied at the variable contract level or by a qualified pension or retirement plan. Any such additional sales charges or other fees or expenses would lower the contract’s or plan’s performance. Current performance may be lower or higher than the performance data quoted. To obtain performance data current to the most recent month-end, please visit our website hartfordfunds.com.

Total returns presented above were calculated using the Fund’s net asset value available to shareholders for sale or redemption of Fund shares on 12/31/2020, which may exclude investment transactions as of this date. All share class returns assume the reinvestment of all distributions at net asset value and the deduction of all fund expenses.

Total returns for the report period presented in the table differs from the return in the Financial Highlights. The total return presented in the Financial Highlights section of the reports is calculated in the same manner, but also takes into account certain adjustments that are necessary under generally accepted accounting principles.

Manager Discussion and Analysis

How did the Fund perform during the period?

The Class IA shares of Hartford Balanced HLS Fund returned 11.62% for the twelve-month period ended December 31, 2020, underperforming the Fund’s blended benchmark, which is comprised of 60% S&P 500 Index, 35% Bloomberg Barclays Government/Credit Bond Index, and 5% ICE BofA US 3-Month Treasury Bill Index, which returned 14.87% for the same period. Individually, the S&P 500 Index, Bloomberg Barclays Government/Credit Bond Index, and ICE BofA US 3-Month Treasury Bill Index returned 18.40%, 8.92%, and 0.67%, respectively, during the period. For the same period, the Class IA shares of the Fund underperformed the 20.51% average return of the Lipper Mixed-Asset Target Allocation Growth Funds peer group, a group of funds that hold between 60%-80% in equity securities, with the remainder invested in bonds, cash, and cash equivalents.

Why did the Fund perform this way?

United States (U.S.) equities, as measured by the S&P 500 Index, posted positive results over the trailing twelve-month period ending December 31, 2020. During the first quarter of 2020, U.S. equities ended lower after achieving record highs in February 2020, as the coronavirus spread rapidly throughout the country, causing unprecedented market disruptions and financial damage, and heightening fears of a severe economic downturn. During the fourth quarter of 2020, U.S. equities rallied, bolstered by better-than-expected third quarter earnings, economic resilience, substantial monetary support from the U.S. Federal Reserve (Fed), and optimism that vaccines will support a broad reopening of the U.S. economy in 2021.

During the twelve-month period, eight of the eleven sectors within the S&P 500 Index posted positive returns, led by the Information Technology (+44%), Consumer Discretionary (+33%), and Communication Services (+24%) sectors, while the Energy (-34%) and Real Estate (-2%) sectors lagged on a relative basis.

Over the period, most global fixed income sectors generated positive returns, driven by a decline in sovereign debt yields across most markets during the period, particularly in the earlier part of 2020 at the onset of

overweight allocation to the Financials sector. This was partially offset by the Fund’s underweight allocations to the Energy and Utilities sectors.

From an individual stock perspective within the equity portion of the Fund, not holding large benchmark constituents such as Apple (Information Technology) and Amazon (Consumer Discretionary), along with the Fund’s overweight position in Noble Energy (Energy), detracted the most from performance relative to the S&P 500 Index. Shares of Apple benefited from a strong iPhone cycle as 5G capabilities go mainstream, and the company also continued to see strength in its growing, high margin services segment (App Store, Apple Pay, and Apple TV+, among others). Shares of e-commerce giant Amazon also rose during 2020 on the back of strong e-commerce demand amid the global pandemic, as well as from the continued growth in its cloud business, Amazon Web Services. Noble Energy was down more than 70% over the course of 2020; the company’s share price rose in the fourth quarter of 2020 on the news that Chevron planned to acquire it.

Top contributors to performance relative to the S&P 500 Index in the equity portion of the Fund included not holding benchmark constituents Wells Fargo (Financials) and AT&T (Communication Services), as well as the Fund’s overweight position in Adobe. Shares of Adobe rose on strong earnings throughout 2020 and management released 2021 guidance that was above consensus estimates. In the fourth quarter of 2020, Adobe’s Digital Media annual recurring revenue grew 22% and Adobe’s Experience Cloud subscriptions grew 14%. Over the past year, Wells Fargo faced significant challenges after being charged with engaging in fraudulent sales practices for more than a decade. In February 2020, the bank announced that it had entered into a $3 billion dollar settlement agreement with the United States Department of Justice and the U.S. Securities and Exchange Commission (SEC). The coronavirus outbreak added further pressure, causing net interest income to fall and provisions for credit losses to rise. The company reported a loss in the second quarter of 2020 driven by large provisions which more than doubled first quarter levels. Finally, in the case of AT&T, the company came under pressure amid challenges in its media and video businesses related to the pandemic.

The fixed income portion of the Fund outperformed the Bloomberg Barclays Government/Credit Bond Index during the period. Security selection within investment-grade credit contributed positively to outperformance relative to the Bloomberg Barclays Government/Credit Bond Index, particularly selection within the Industrials and Financials sectors during the period. Within non-corporate credit, security selection and an underweight to local agency securities were the primary contributors. Out-of-benchmark allocations to agency mortgage-backed securities (MBS) pass-throughs and collateralized loan obligations (CLOs) contributed positively to relative performance. An out-of-benchmark allocation to commercial mortgage-backed securities (CMBS) moderately detracted from relative performance over the period. Duration/yield curve positioning also detracted from relative performance as the Fund was positioned with underweight positions to the short and long end of the yield curve during the period.

Derivatives were not used in a significant manner in the Fund during the period and did not have a material impact on performance during the period.

Composition by Security Type⁽¹⁾

as of 12/31/2020

Average Annual Total Returns

for the Periods Ending 12/31/2020

PERFORMANCE DATA QUOTED REPRESENTS PAST PERFORMANCE AND DOES NOT GUARANTEE FUTURE RESULTS. The investment return and principal value of the investment will fluctuate so that investors’ shares, when redeemed, may be worth more or less than their original cost. The table and chart do not reflect the deductions of taxes, sales charges or other fees which may be applied at the variable contract level or by a qualified pension or retirement plan. Any such additional sales charges or other fees or expenses would lower the contract’s or plan’s performance. Current performance may be lower or higher than the performance data quoted. To obtain performance data current to the most recent month-end, please visit our website hartfordfunds.com.

Total returns presented above were calculated using the Fund’s net asset value available to shareholders for sale or redemption of Fund shares on 12/31/2020, which may exclude investment transactions as of this date. All share class returns assume the reinvestment of all distributions at net asset value and the deduction of all fund expenses.

Total returns for the report period presented in the table differs from the return in the Financial Highlights. The total return presented in the Financial Highlights section of the reports is calculated in the same manner, but also takes into account certain adjustments that are necessary under generally accepted accounting principles.

Class IC shares commenced operations on 04/30/2014. Class IC shares performance prior to that date reflects Class IA shares performance adjusted to reflect the 12b-1 fee of 0.25% and the administrative services fee of 0.25% applicable to Class IC shares. The performance after such date reflects actual Class IC shares performance.

You cannot invest directly in an index.

Manager Discussion and Analysis

How did the Fund perform during the period?

The Class IA shares of Hartford Capital Appreciation HLS Fund returned 21.91% for the twelve-month period ended December 31, 2020, outperforming the Fund’s benchmarks, the Russell 3000 Index, which returned 20.89% for the same period, and the S&P 500 Index, which returned 18.40% for the same period. For the same period, the Class IA shares of the Fund also outperformed the 15.73% average return of the Lipper Multi-Cap Core Funds peer group, a group of funds with investment strategies similar to those of the Fund.

Why did the Fund perform this way?

United States (U.S.) equities, as measured by the Russell 3000 Index, posted positive results over the trailing twelve-month period ending December 31, 2020. During the first quarter of 2020, U.S. equities ended lower after achieving record highs in February 2020, as the coronavirus spread rapidly throughout the country, causing unprecedented market disruptions and financial damage, and heightening fears of a severe economic downturn. Many states adopted extraordinary measures to fight the contagion, while companies shuttered stores and production, withdrew earnings guidance, and drew down credit lines at a record pace as borrowing costs soared. Volatility surged to extreme levels, and the S&P 500 Index suffered its fastest-ever decline into a bear market.

During the second quarter of 2020, U.S. equities finished higher after an extraordinary rally drove U.S. equities to their largest quarterly gain since the fourth quarter of 1998. The unprecedented scale of the fiscal and monetary stimulus implemented by Congress and the U.S. Federal Reserve (Fed) in response to the pandemic was the most influential driver of the market’s rebound in the second quarter of 2020. Risk sentiment eased towards the end of the quarter on concerns about a sharp rise in infections in some southern and western states, the rapid speed of the market’s rebound, and cautious comments from the Fed regarding the economic outlook.

In the third quarter of 2020, U.S. equities extended their strong rally, as markets were bolstered by ongoing monetary support from the Fed, a broadening U.S. economic recovery, better-than-expected corporate earnings, and promising trials for coronavirus vaccines. The U.S. economy gradually recovered during the third quarter; however, the path to a sustainable economic recovery was clouded by concerns about a resurgence in coronavirus infections in many areas of the country, an undetermined timeline for vaccines, high unemployment, elevated debt burdens, and uncertainty about additional fiscal stimulus.

U.S. equities rose again in the fourth quarter of 2020, bolstered by better-than-expected third-quarter 2020 earnings, economic resilience, substantial monetary support from the Fed and optimism that vaccines would support a broad reopening of the U.S. economy in 2021. A sharp escalation in coronavirus infections across the country and renewed restrictions to curb the spread of the virus were overshadowed by highly

share price of Square, a credit card processing solutions company, surged higher as lockdown measures related to the spread of coronavirus continued the need for merchants to process transactions electronically. Strong momentum in the company’s Cash App also helped contribute to positive performance. As of the end of the period, the Fund remained overweight the stock relative to the Russell 3000 Index. Roku, a streaming platform for television, reported solid user growth in the first quarter of 2020 but it was only a slight acceleration from the prior quarter. Despite a surge in over-the-top (OTT) viewing during the period, advertiser spending weakened as a result of the global pandemic. The second quarter of 2020 resulted in revenue in excess of analyst estimates; however, the outlook for the resumption of advertiser spending remained uncertain, with expectations that it could take until 2021 to recover to pre-pandemic levels. Towards the end of the period, Roku reported strong third-quarter 2020 results as advertising revenue bounced back and drove growth. The company recognized over 40% growth in active accounts. During the period, we trimmed the Fund’s exposure to the company on share-price strength but as of the end of the period, the Fund remained overweight in the stock relative to the Russell 3000 Index.

The largest detractors from relative performance during the period were underweight exposures to Apple (Information Technology), Tesla (Consumer Discretionary), and Microsoft (Information Technology). Apple designs, manufactures, and sells personal computers, tablets, wearables, and a variety of related services. The share price of Apple moved higher during the period on quarterly earnings and revenue ahead of consensus estimates. The company participated in a four-for-one stock split during the period. As of the end of the period, we continued to hold an underweight position in the stock relative to the Russell 3000 Index. Tesla engages in the design, development, manufacture, and sale of fully electric vehicles, energy generation and storage systems. Shares of the company moved higher during the period as the company reported its fourth consecutive quarter of profitability which many viewed as the last hurdle towards Tesla’s inclusion in the S&P 500 Index. The stock entered the S&P 500 Index at the end of 2020 and shares moved higher amid positive investor sentiment. We initiated a small position in the stock during the period, which we subsequently sold later in the period as we sought to capitalize on strength while pursuing other opportunities that we believed would provide better risk and return profiles. Microsoft, a company that engages in the development and support of software, services, devices, and solutions, performed well during the beginning of the period with stay-at-home and remote-work related businesses (Teams, Gaming, virtual desktop) gaining traction. The stock continued to move higher during the period before giving back some gains after it was announced that the company’s bid for video-sharing site TikTok was not accepted. In the fourth quarter of 2020, the company reported strong quarterly results with growth in its cloud business and acceleration in commercial bookings. The market reacted negatively, however, to management’s issued guidance for the upcoming quarter which noted expected weakness in personal computing and Xbox supply constraints. As of the end of the period, the Fund remained underweight to the stock relative to the Russell 3000 Index.

During the period, the Fund, at times, used derivative instruments such as currency forwards to hedge currency risk and/or equity index futures to hedge the market risk. During the period, the use of currency forwards

Average Annual Total Returns

for the Periods Ending 12/31/2020

PERFORMANCE DATA QUOTED REPRESENTS PAST PERFORMANCE AND DOES NOT GUARANTEE FUTURE RESULTS. The investment return and principal value of the investment will fluctuate so that investors’ shares, when redeemed, may be worth more or less than their original cost. The table and chart do not reflect the deductions of taxes, sales charges or other fees which may be applied at the variable contract level or by a qualified pension or retirement plan. Any such additional sales charges or other fees or expenses would lower the contract’s or plan’s performance. Current performance may be lower or higher than the performance data quoted. To obtain performance data current to the most recent month-end, please visit our website hartfordfunds.com.

Total returns presented above were calculated using the Fund’s net asset value available to shareholders for sale or redemption of Fund shares on 12/31/2020, which may exclude investment transactions as of this date. All share class returns assume the reinvestment of all distributions at net asset value and the deduction of all fund expenses.

Total returns for the report period presented in the table differs from the return in the Financial Highlights. The total return presented in the Financial Highlights section of the reports is calculated in the same manner, but also takes into account certain adjustments that are necessary under generally accepted accounting principles.

Class IC shares commenced operations on 09/18/2020. Class IC shares performance prior to that date reflects Class IA shares performance adjusted to reflect the 12b-1 fee of 0.25% and the administrative services fee of 0.25% applicable to Class IC shares. The performance after such date reflects actual Class IC shares performance.

You cannot invest directly in an index.

See “Benchmark Glossary” for benchmark descriptions.

Manager Discussion and Analysis

How did the Fund perform during the period?

The Class IA shares of the Hartford Disciplined Equity HLS Fund returned 18.04% for the twelve-month period ended December 31, 2020, underperforming the Fund’s benchmark, the S&P 500 Index, which returned 18.40% for the same period. For the same period, the Class IA shares of the Fund slightly outperformed the 17.29% average return of the Lipper Large-Cap Core Funds peer group, a group of funds with investment strategies similar to those of the Fund.

Why did the Fund perform this way?

United States (U.S.) equities, as measured by the S&P 500 Index, posted positive results over the trailing twelve-month period ended December 31, 2020. U.S. equities ended the first quarter of 2020 sharply lower after achieving record highs in February 2020, as the coronavirus spread rapidly throughout the country, causing unprecedented market disruptions and financial damage, and heightening fears of a severe economic downturn. Many states adopted extraordinary measures to fight the contagion, while companies shuttered stores and production, withdrew earnings guidance, and drew down credit lines at a record pace as borrowing costs soared. Volatility surged to extreme levels, and the S&P 500 Index suffered its fastest-ever decline into a bear market.

U.S. equities ended the second quarter of 2020 higher after an extraordinary rally drove U.S. equities to their largest quarterly gain since the fourth quarter of 1998. The unprecedented scale of the fiscal and monetary stimulus implemented by Congress and the U.S. Federal Reserve (Fed) in response to the pandemic was the most influential driver of the market’s rebound in the second quarter of 2020. Risk sentiment eased at the end of the second quarter on concerns about a sharp rise in infections in some southern and western states, the rapid speed of the market’s rebound, and cautious comments from the Fed regarding the economic outlook.

In the third quarter of 2020, U.S. equities extended their strong rally, with markets bolstered by substantial monetary support from the Fed, a broadening U.S. economic recovery, better-than-expected corporate earnings, and promising trials for coronavirus vaccines. The U.S. economy gradually recovered during the third quarter; however, the path to a sustainable economic recovery was clouded by concerns about a resurgence in coronavirus infections in many areas of the country, an undetermined timeline for vaccines, high unemployment, elevated debt burdens, and uncertainty about additional fiscal stimulus. In September, the S&P 500 Index declined for the first time in five months. The Fed signaled its expectation to hold interest rates near zero until inflation is on track to moderately exceed 2%.

stay-at-home policies during the year, physical occupancy within the company’s properties was low. We sold this position in the Fund during the period. Shares of chip maker NVIDIA rose during the period after reporting consecutively strong quarterly results. NVIDIA has benefited from much of the world working and learning from home as sales of laptops and game consoles using NVIDIA chips lifted earnings for the company. Not owning the stock during the period was a detractor from Fund performance due to the stock’s strong performance.

The largest contributors to the Fund’s performance relative to the S&P 500 Index over the period were not owning both Exxon Mobil (Energy) and Wells Fargo (Financials), which are each constituents of the S&P 500 Index, as well as an overweight holding in Teradyne (Information Technology). Shares of the oil- and gas-producing company Exxon Mobil came under pressure the past year due to a decrease in crude oil and natural gas prices amid escalating concerns of a slowing macroeconomic environment. Not owning the stock was a positive contributor over the period due to poor performance. Shares of Wells Fargo declined over the year after reporting consecutive disappointing quarterly results. In July, the company announced it set aside a record $9.5 billion for credit losses. Executives warned they would earmark more for soured loans as the pandemic continued to rage throughout the U.S. and weigh on companies and workers. Falling yields have also negatively affected the bank. Not owning the stock was a positive contributor to Fund performance over the period due to the stock’s poor performance. Shares of Teradyne, an automated test equipment and industrial automation company, rose during the period. Towards the end of the period, the company released third-quarter earnings that beat consensus and guided revenue expectations for the fourth quarter higher.

Derivatives were not used in a significant manner in the Fund during the period and did not have a material impact on performance during the period.

What is the outlook as of the end of the period?

We are keeping an eye on the Georgia runoff election for the Senate, and whether control of the Senate will flip to the Democrats. Depending on the outcome, we will consider various policy implications from that event, including if there is alignment of majorities for both legislative houses and the presidency.

It is encouraging that there is an effort underway to vaccinate the population even if the pace of the initial rollout has been disappointing relative to earlier expectations. Despite worries about different strains, at least so far, we remain optimistic about the potential for putting the pandemic behind us this year. Given the efficacy of the various vaccines, there still may be some lasting lifestyle changes and we are mindful of this development. Despite these changes, we expect unemployment rates to come down in 2021 as a recovery takes hold, especially in some of the hardest-hit industries.

We remain cautious, being mindful of pockets of extreme speculation and valuations that are hard to justify. On the positive side, we believe the combination of a high savings rate, stimulus payments, and rehiring more recently implies a very healthy consumer when the economic recovery takes shape.

As always, we continue to focus on the long term. While we did make some changes to portfolio holdings in the Fund during the period, we continue to be incremental and mindful of the impact of volatility.

Average Annual Total Returns

for the Periods Ending 12/31/2020

PERFORMANCE DATA QUOTED REPRESENTS PAST PERFORMANCE AND DOES NOT GUARANTEE FUTURE RESULTS. The investment return and principal value of the investment will fluctuate so that investors’ shares, when redeemed, may be worth more or less than their original cost. The table and chart do not reflect the deductions of taxes, sales charges or other fees which may be applied at the variable contract level or by a qualified pension or retirement plan. Any such additional sales charges or other fees or expenses would lower the contract’s or plan’s performance. Current performance may be lower or higher than the performance data quoted. To obtain performance data current to the most recent month-end, please visit our website hartfordfunds.com.

Total returns presented above were calculated using the Fund’s net asset value available to shareholders for sale or redemption of Fund shares on 12/31/2020, which may exclude investment transactions as of this date. All share class returns assume the reinvestment of all distributions at net asset value and the deduction of all fund expenses.

Total returns for the report period presented in the table differs from the return in the Financial Highlights. The total return presented in the Financial Highlights section of the reports is calculated in the same manner, but also takes into account certain adjustments that are necessary under generally accepted accounting principles.

You cannot invest directly in an index.

See “Benchmark Glossary” for benchmark descriptions.

As shown in the Fund’s current prospectus, the total annual fund operating expense ratios for Class IA and Class IB were 0.66% and 0.91%, respectively. Gross and net expenses are the same. Actual expenses may be higher or lower. Please see the accompanying Financial Highlights for expense ratios for the period ended 12/31/2020.

Manager Discussion and Analysis

How did the Fund perform during the period?

The Class IA shares of Hartford Dividend and Growth HLS Fund returned 7.77% for the twelve-month period ended December 31, 2020, underperforming the Fund’s benchmark, the S&P 500 Index, which returned 18.40% for the same period, and outperforming the Fund’s other benchmark, the Russell 1000 Value Index, which returned 2.80% for the same period. For the same period, the Class IA shares of the Fund outperformed the 4.27% average return of the Lipper Equity Income Funds peer group, a group of funds with investment strategies similar to those of the Fund.

Why did the Fund perform this way?

United States (U.S.) equities, as measured by the S&P 500 Index, posted positive results over the trailing twelve-month period ended December 31, 2020. U.S. equities ended the first quarter of 2020 sharply lower after achieving record highs in February 2020, as the coronavirus spread rapidly throughout the country, causing unprecedented market disruptions and financial damage, and heightening fears of a severe economic downturn. Many states adopted extraordinary measures to fight the contagion, while companies shuttered stores and production, withdrew earnings guidance, and drew down credit lines at a record pace as borrowing costs soared. Volatility surged to extreme levels, and the S&P 500 Index suffered its fastest-ever decline into a bear market.

U.S. equities ended the second quarter of 2020 higher after an extraordinary rally drove U.S. equities to their largest quarterly gain since the fourth quarter of 1998. The unprecedented scale of the fiscal and monetary stimulus implemented by Congress and the U.S. Federal Reserve (Fed) in response to the pandemic was the most influential driver of the market’s rebound in the second quarter of 2020. Risk sentiment eased at the end of the second quarter on concerns about a sharp rise in infections in some southern and western states, the rapid speed of the market’s rebound, and cautious comments from the Fed regarding the economic outlook.

In the third quarter of 2020, U.S. equities extended their strong rally, with markets bolstered by substantial monetary support from the Fed, a broadening U.S. economic recovery, better-than-expected corporate earnings, and promising trials for coronavirus vaccines. The U.S. economy gradually recovered during the third quarter; however, the path to a sustainable economic recovery was clouded by concerns about a resurgence in coronavirus infections in many areas of the country, an undetermined timeline for vaccines, high unemployment, elevated debt burdens, and uncertainty about additional fiscal stimulus. In September, the S&P 500 Index declined for the first time in five months. The Fed signaled its expectation to hold interest rates near zero until inflation is on track to moderately exceed 2%.

Treasury notes fell to levels not seen since 2016, narrowing the spread on the bank’s longer-term assets funded with shorter-term liabilities. Broadly speaking, the Energy sector was the worst performing sector as the correction in oil prices was set off by the failed Organization of the Petroleum Exporting Countries Plus supply agreement and was further exacerbated by severe demand reduction due to restrictions on global economic activity. At the end of the period, shares of Suncor were under pressure driven by lower commodity prices and elevated costs and expenses. We eliminated the Fund’s position in the first quarter of 2020 as we preferred large integrated Energy companies.

Top contributors to Fund performance relative to the S&P 500 Index over the period included underweight allocations to Exxon Mobil (Energy) and Wells Fargo (Financials), as well as an overweight to Deere & Co (Industrials). ExxonMobil (Energy) was a top contributor to relative performance during the period, as we exited the position prior to the energy market collapse in March 2020. Not owning shares of Well Fargo contributed to relative performance as the company’s shares fell over the period after the chief financial officer predicted higher loan-loss provisions in addition to a sharp drop in interest income for the year. Deere & Co shares rose during the period as it reported strong earnings results and increased its sales outlook for the year as demand remained resilient despite the uncertainty related to the coronavirus pandemic.

Derivatives were not used in a significant manner in the Fund during the period and did not have a material impact on performance during the period.

What is the outlook as of the end of the period?

The market continued its positive trajectory in the fourth quarter of 2020, bolstered by enthusiasm around the positive vaccine announcements. Now that the U.S. Food and Drug Administration (FDA) has approved a number of vaccines, we believe a successful distribution and administration of the vaccine may allow the economy to regain some normalcy by the end of the year. Despite this clear positive, risks remain such as rising geopolitical uncertainty, new waves of the coronavirus, and massive debt. That being said, we believe that many areas of the market were overlooked in 2020. Our framework during these turbulent times has been to seek to avoid balance sheet risk while seeking to identify mispriced opportunities that have the potential to create enormous value on the other side of the pandemic.

At the end of the period, the Fund remained most overweight in the Financials and Energy sectors and most underweight in the Information Technology and Consumer Discretionary sectors, relative to the S&P 500 Index.

In the face of great uncertainty, we remain focused on seeking to invest the Fund’s assets in companies that we believe to have reasonable valuations, with attractive long-term free cash flow generation, solid balance sheets, and resilient fundamentals.

Important Risks

Investing involves risk, including the possible loss of principal. Security prices fluctuate in value depending on general market and economic conditions and the prospects of individual companies. •For dividend-paying stocks, dividends are not guaranteed and may decrease without notice. •Foreign investments may be more volatile and less liquid than U.S. investments and are subject to the risk of currency fluctuations and adverse political and economic developments.

Average Annual Total Returns

for the Periods Ending 12/31/2020

PERFORMANCE DATA QUOTED REPRESENTS PAST PERFORMANCE AND DOES NOT GUARANTEE FUTURE RESULTS. The investment return and principal value of the investment will fluctuate so that investors’ shares, when redeemed, may be worth more or less than their original cost. The table and chart do not reflect the deductions of taxes, sales charges or other fees which may be applied at the variable contract level or by a qualified pension or retirement plan. Any such additional sales charges or other fees or expenses would lower the contract’s or plan’s performance. Current performance may be lower or higher than the performance data quoted. To obtain performance data current to the most recent month-end, please visit our website hartfordfunds.com.

Total returns presented above were calculated using the Fund’s net asset value available to shareholders for sale or redemption of Fund shares on 12/31/2020, which may exclude investment transactions as of this date. All share class returns assume the reinvestment of all distributions at net asset value and the deduction of all fund expenses.

Total returns for the report period presented in the table differs from the return in the Financial Highlights. The total return presented in the Financial Highlights section of the reports is calculated in the same manner, but also takes into account certain adjustments that are necessary under generally accepted accounting principles.

You cannot invest directly in an index.

See “Benchmark Glossary” for benchmark descriptions.

As shown in the Fund’s current prospectus, the total annual fund operating expense ratios for Class IA and Class IB were 0.92% and 1.17%, respectively. Gross and net expenses are the same. Expenses shown include acquired fund fees and expenses. Actual expenses

Manager Discussion and Analysis

How did the Fund perform during the period?

The Class IA shares of Hartford Healthcare HLS Fund returned 23.10% for the twelve-month period ended December 31, 2020, outperforming the Fund’s benchmarks, the S&P Composite 1500 Health Care Index, which returned 14.55% for the same period, and the S&P 500 Index, which returned 18.40% for the same period. For the same period, the Class IA shares of the Fund outperformed the 12.77% average return of the Lipper Global Health and Biotechnology peer group, a group of funds with investment strategies similar to those of the Fund.

Why did the Fund perform this way?

United States (U.S.) healthcare equities underperformed the broader U.S. market and global equity market during the period, as measured by the S&P Composite 1500 Health Care Index, S&P 500 Index, and the MSCI World Index, respectively. Within the S&P Composite 1500 Health Care Index, mid-cap biopharma returned 23%, medical technology returned 22%, healthcare services returned 15%, large-cap biopharma returned 8%, and small-cap biopharma returned 2% for the period.

The Fund outperformed the S&P Composite 1500 Health Care Index over the period primarily because of favorable security selection decisions. Security selection was strongest in mid- and small-cap biopharma. Sector allocation detracted from performance relative to the S&P Composite 1500 Health Care Index. An overweight to small-cap biopharma and the Fund’s cash position detracted from results relative to the S&P Composite 1500 Health Care Index during the period, offsetting positive results from an overweight to mid-cap biopharma and an underweight to large-cap biopharma.

Forty Seven (small-cap biopharma), Momenta Pharmaceuticals (mid-cap biopharma), and Zai Lab (mid-cap biopharma) were the top contributors to performance relative to the S&P Composite 1500 Health Care Index. In March, Forty Seven, a U.S.-based development-stage targeted oncology company, announced an agreement in which Gilead Sciences would acquire Forty Seven for $4.9 billion, a 60% premium to the stock’s February 2020 end-of-month closing price. Shares of Momenta Pharmaceuticals, a U.S.-based biopharmaceutical company focused on

better-than-expected first- and third-quarter earnings results and maintained full year guidance, driven by sales of top arthritis drug Humira. Boston Scientific, Anthem, and Medtronic were top detractors from absolute performance during the period.

Derivatives were not used in a significant manner in the Fund during the period and did not have a material impact on performance during the period.

What is the outlook as of the end of the period?

We expect the human and economic impact of the coronavirus pandemic to remain challenging but remain optimistic about the rollout of effective vaccines underway. Essential workers and certain high-risk parts of the population have been prioritized to receive initial doses of the vaccine. We are closely monitoring the emergence of novel variants of the SARS-CoV-2 virus, which started in the United Kingdom and South Africa and has now spread globally. Based on available data and the design of the vaccines, we expect the vaccines targeting the viral spike protein may offer protection against the novel variants.

Beyond vaccine development, the coronavirus crisis highlighted the need for more significant testing infrastructure in developed and emerging markets, which we believe may continue to drive demand within the diagnostics industry. Furthermore, we anticipate medical device trends and hospital utilization to recover gradually, as many medical procedures cannot be deferred indefinitely, and we believe that vaccine availability should likely continue to restore patient confidence in accessing the system.

The biopharmaceutical industry has come together in response to this pandemic by spending Research & Development (R&D) dollars to develop treatments and vaccines for coronavirus, while seeking minimal profits. We expect the financial benefit of successful treatments to be minimal and short-term for the companies developing them, yet we anticipate the goodwill will create a halo-effect for the industry. Additionally, President-elect Joe Biden will take office in January 2021 and we believe he is likely to govern as a centrist. This would be a favorable outcome, as it would likely be supportive of more moderate healthcare policies in our view. This scenario increases the likelihood of manageable drug price legislation sometime in 2021 or 2022, which could remove the five-year overhang on the industry.

In selecting stocks for the Fund, we seek companies that develop innovative products designed to address important unmet medical needs. Over the long term, we expect the tailwinds of innovation, an aging population, and the globalization of demand for cutting-edge Western-style medicines are likely to continue to drive growth of the sector.

Important Risks

Investing involves risk, including the possible loss of principal. Security prices fluctuate in value depending on general market and economic conditions and the prospects of individual companies. •Risks of focusing investments on the healthcare related sector include regulatory and legal developments, patent considerations, intense competitive pressures, rapid technological changes, potential product obsolescence, and liquidity risk. •Small- and mid-cap securities can have greater risks and volatility than large-cap securities. •Foreign investments may be more volatile and less liquid than U.S. investments and are subject to the risk of currency fluctuations and adverse political and economic developments. These risks may be greater for investments in emerging markets.

Average Annual Total Returns

for the Periods Ending 12/31/2020

PERFORMANCE DATA QUOTED REPRESENTS PAST PERFORMANCE AND DOES NOT GUARANTEE FUTURE RESULTS. The investment return and principal value of the investment will fluctuate so that investors’ shares, when redeemed, may be worth more or less than their original cost. The table and chart do not reflect the deductions of taxes, sales charges or other fees which may be applied at the variable contract level or by a qualified pension or retirement plan. Any such additional sales charges or other fees or expenses would lower the contract’s or plan’s performance. Current performance may be lower or higher than the performance data quoted. To obtain performance data current to the most recent month-end, please visit our website hartfordfunds.com.

Total returns presented above were calculated using the Fund’s net asset value available to shareholders for sale or redemption of Fund shares on 12/31/2020, which may exclude investment transactions as of this date. All share class returns assume the reinvestment of all distributions at net asset value and the deduction of all fund expenses.

Total returns for the report period presented in the table differs from the return in the Financial Highlights. The total return presented in the Financial Highlights section of the reports is calculated in the same manner, but also takes into account certain adjustments that are necessary under generally accepted accounting principles.

You cannot invest directly in an index.

See “Benchmark Glossary” for benchmark descriptions.

As shown in the Fund’s current prospectus, the total annual fund operating expense ratios for Class IA and Class IB were 0.74% and 0.99%, respectively. Gross and net expenses

are the same. Actual expenses may be higher or lower. Please see the accompanying Financial Highlights for expense ratios for the period ended 12/31/2020.

Manager Discussion and Analysis

How did the Fund perform during the period?

The Class IA of the Hartford International Opportunities HLS Fund returned 20.45% for the twelve-month period ended December 31, 2020, outperforming the Fund’s benchmark, the MSCI ACWI ex USA Index (Net), which returned 10.65% for the same period. For the same period, Class IA shares of the Fund outperformed the 14.42% average return of the Lipper International Large-Cap Growth Fund peer group, a group of funds with investment strategies similar to those of the Fund.

Why did the Fund perform this way?

For the twelve-month period ended December 31, 2020, international equities rose 10.65%, as measured by the MSCI ACWI ex USA Index (Net). In the first-quarter of 2020, international equities ended sharply lower. The coronavirus spread rapidly across the globe, causing unprecedented disruption to financial markets and economies and overshadowing optimism about a phase-one trade deal between the United States (U.S.) and China. The World Health Organization (WHO) declared the coronavirus outbreak a pandemic. Market volatility remained extremely high, and liquidity plunged to record lows. In response, the U.S. government unleashed a massive fiscal stimulus plan to stem economic damage. The European Union (EU) suspended budget and borrowing rules to give governments more fiscal flexibility to deal with the crisis. The price of oil plunged to its lowest level since 2002.

International equity markets surged during the second quarter of 2020. Markets were fueled by optimism about successful early-stage trials for a potential coronavirus vaccine, ongoing fiscal and monetary stimulus, and signs that global economic activity was improving. As new infections declined in most countries, governments shifted their focus toward gradually lifting lockdown restrictions and supporting the recovery of their economies. The European Commission announced a proposal for a €750 billion (US$912 billion) recovery fund to provide grants and loans to Eurozone economies that had been devastated by the coronavirus pandemic. After plummeting to historic lows in April 2020 amid a pandemic-induced collapse in demand, oil rebounded later in the quarter as the global economy began to recover.

International equities rose in the third quarter of 2020. Markets were bolstered by the impact of the massive fiscal and monetary stimulus from governments and central banks, further signs of a recovery in global economic growth, and the potential for coronavirus vaccines in the near future. However, the recovery was threatened by the pandemic as the worldwide death toll and infections increased. The EU reached an agreement on a €750 billion recovery fund to aid countries in the region that had been most severely impacted by the pandemic. The U.S. dealt with political uncertainty ahead of the 2020 presidential election and a

lack of additional fiscal stimulus. Negotiations surrounding the United Kingdom’s (U.K.’s) exit from the EU (also known as Brexit) deteriorated

declining sales amid coronavirus-related travel restrictions in the first half of 2020, the company reported signs of rapid recovery in the latter half of the year. China’s Golden Week holiday also supported sales in China, as shoppers spent more in their home country rather than traveling overseas. The stock price for Zalando, a European e-commerce company offering fashion and lifestyle products, ended the period higher. The company reported strong revenue growth in the second and third quarters of 2020, as lockdowns sparked an increased interest in digital shopping.

Top detractors from Fund performance relative to the MSCI ACWI ex USA Index (Net) during the period included AerCap (Industrials), Ovintiv (Energy), and Airbus (Industrials). Shares of the Irish aircraft leasing company AerCap fell over the period. In the first quarter of 2020, AerCap announced its intention to draw down on its $6.6 billion credit line to shore up capital and prevent shortfalls amid coronavirus pandemic concerns. The decline in the demand for air travel due to coronavirus has put pressure on AerCap’s leasing operations. With these challenges in mind, we eliminated the Fund’s position in favor of opportunities with more favorable risk/reward profiles in our view. Ovintiv stock fell after the American exploration and production company took drastic action to reduce second quarter costs amid falling oil prices. We eliminated the Fund’s position during the period and redeployed capital into opportunities with more favorable risk/reward in our view. Shares of the European aerospace corporation Airbus fell over the period as the company’s aircraft deliveries have continued to be impacted during the coronavirus pandemic. The company also announced plans for further furloughs and the possibility of shortening work time, among other considerations to reduce layoffs. As of the end of the period, the Fund continued to hold the stock.

Derivatives were not used in a significant manner in the Fund during the period and did not have a material impact on performance during the period.

What is the outlook as of the end of the period?

Markets continued to recover over the fourth quarter of 2020 as the global economy has continued to gradually emerge from lockdown. However, sporadic lockdowns and regional regressions have driven persistent volatility. Across markets, the recovery broadened out as more cyclicals and interest-rate sensitive companies participated in the rally over the quarter. As of the end of the period, we continued to trim companies that have outperformed this year and rotate capital into companies in sectors that have lagged where we see better fundamentals going forward.

We continue to track the spread and evolution of the coronavirus as well as the global economic recovery – particularly fiscal and monetary stimulus and shifts in consumption behavior. We are mindful that equity market valuations, especially for high-growth business models, have risen this year. Amid this valuation landscape and the heightened uncertainty associated with the pandemic, we are finding what we view as compelling opportunities in companies that have improved their competitive advantages during the lockdown, are geared to the reopening of economies, or have pricing power, making them well positioned in our view to benefit from supply-demand imbalance across end markets. We continue to be focused on companies where we believe the market does not fully appreciate the impact of these factors on future returns on capital.

Average Annual Total Returns

for the Periods Ending 12/31/2020

PERFORMANCE DATA QUOTED REPRESENTS PAST PERFORMANCE AND DOES NOT GUARANTEE FUTURE RESULTS. The investment return and principal value of the investment will fluctuate so that investors’ shares, when redeemed, may be worth more or less than their original cost. The table and chart do not reflect the deductions of taxes, sales charges or other fees which may be applied at the variable contract level or by a qualified pension or retirement plan. Any such additional sales charges or other fees or expenses would lower the contract’s or plan’s performance. Current performance may be lower or higher than the performance data quoted. To obtain performance data current to the most recent month-end, please visit our website hartfordfunds.com.

Total returns presented above were calculated using the Fund’s net asset value available to shareholders for sale or redemption of Fund shares on 12/31/2020, which may exclude investment transactions as of this date. All share class returns assume the reinvestment of all distributions at net asset value and the deduction of all fund expenses.

Total returns for the report period presented in the table differs from the return in the Financial Highlights. The total return presented in the Financial Highlights section of the reports is calculated in the same manner, but also takes into account certain adjustments that are necessary under generally accepted accounting principles.

You cannot invest directly in an index.

See “Benchmark Glossary” for benchmark descriptions.

As shown in the Fund’s current prospectus, the total annual fund operating expense ratios for Class IA and Class IB were 0.70% and 0.95%, respectively. Gross and net expenses are the same. Actual expenses may be higher or lower. Please see the accompanying Financial Highlights for expense ratios for the period ended 12/31/2020.

Manager Discussion and Analysis

How did the Fund perform during the period?

The Class IA shares of Hartford MidCap HLS Fund returned 25.10% for the twelve-month period ended December 31, 2020, outperforming the Fund’s benchmark, the S&P MidCap 400 Index, which returned 13.66% for the same period. For the same period, the Class IA shares of the Fund underperformed the 40.09% average return of the Lipper Mid-Cap Growth Funds peer group, a group of funds with investment strategies similar to those of the Fund.

Why did the Fund perform this way?

United States (U.S.) equities, as measured by the S&P 500 Index, posted positive results over the trailing twelve-month period ended December 31, 2020. U.S. equities ended the first quarter of 2020 sharply lower after achieving record highs in February 2020, as the coronavirus spread rapidly throughout the country, causing unprecedented market disruptions and financial damage, and heightening fears of a severe economic downturn. U.S. equities ended the second quarter of 2020 higher after an extraordinary rally drove U.S. equities to their largest quarterly gain since the fourth quarter of 1998. The unprecedented scale of the fiscal and monetary stimulus implemented by Congress and the U.S. Federal Reserve (Fed) in response to the pandemic was the most influential driver of the market’s rebound in the second quarter of 2020.

In the third quarter of 2020, U.S. equities extended their strong rally, with markets bolstered by substantial monetary support from the Fed, a broadening U.S. economic recovery, better-than-expected corporate earnings, and promising trials for coronavirus vaccines. The U.S. economy gradually recovered during the third quarter of 2020; however, the path to a sustainable economic recovery was clouded by concerns about a resurgence in coronavirus infections in many areas of the country, an undetermined timeline for vaccines, high unemployment, elevated debt burdens, and uncertainty about additional fiscal stimulus.

During the fourth quarter of 2020, U.S. equities rallied, bolstered by better-than-expected third-quarter 2020 earnings, economic resilience, substantial monetary support from the Fed, and optimism that vaccines will support a broad reopening of the U.S. economy in 2021. A sharp escalation in coronavirus infections across the country and renewed restrictions to curb the spread of the coronavirus were overshadowed by highly encouraging vaccine developments. Joe Biden was elected president, removing a key element of uncertainty for the market.

Returns during the period varied by market cap. Small-cap equities, as measured by the Russell 2000 Index, outperformed mid-cap and large-cap equities, as measured by the S&P MidCap 400 Index and S&P 500 Index, respectively. Seven of the eleven sectors within the S&P MidCap 400 Index posted positive returns led by the Information Technology (+36%), Consumer Discretionary (+31%), and Healthcare (+30%)

Average Annual Total Returns

for the Periods Ending 12/31/2020

PERFORMANCE DATA QUOTED REPRESENTS PAST PERFORMANCE AND DOES NOT GUARANTEE FUTURE RESULTS. The investment return and principal value of the investment will fluctuate so that investors’ shares, when redeemed, may be worth more or less than their original cost. The table and chart do not reflect the deductions of taxes, sales charges or other fees which may be applied at the variable contract level or by a qualified pension or retirement plan. Any such additional sales charges or other fees or expenses would lower the contract’s or plan’s performance. Current performance may be lower or higher than the performance data quoted. To obtain performance data current to the most recent month-end, please visit our website hartfordfunds.com.

Total returns presented above were calculated using the Fund’s net asset value available to shareholders for sale or redemption of Fund shares on 12/31/2020, which may exclude investment transactions as of this date. All share class returns assume the reinvestment of all distributions at net asset value and the deduction of all fund expenses.

Total returns for the report period presented in the table differs from the return in the Financial Highlights. The total return presented in the Financial Highlights section of the reports is calculated in the same manner, but also takes into account certain adjustments that are necessary under generally accepted accounting principles.

You cannot invest directly in an index.

See “Benchmark Glossary” for benchmark descriptions.

As shown in the Fund’s current prospectus, the total annual fund operating expense ratios for Class IA and Class IB were 0.66% and 0.91%, respectively. Gross and net expenses are the same. Expenses shown include acquired fund fees and expenses. Actual expenses may be higher or lower. Please see the accompanying Financial Highlights for expense ratios for the period ended 12/31/2020.

Manager Discussion and Analysis

How did the Fund perform during the period?

The Class IA shares of Hartford Small Cap Growth HLS Fund returned 33.20% for the twelve-month period ended December 31, 2020, underperforming its benchmark, the Russell 2000 Growth Index, which returned 34.63%. For the same period, the Class IA shares of the Fund also underperformed the 36.91% average return of the Lipper Small-Cap Growth Funds peer group, a group of funds with investment strategies similar to those of the Fund.

Why did the Fund perform this way?

United States (U.S.) equities, as measured by the S&P 500 Index, posted positive results over the trailing twelve-month period ending December 31, 2020. U.S. equities ended the first quarter of 2020 sharply lower after achieving record highs in February 2020, as the coronavirus spread rapidly throughout the country, causing unprecedented market disruptions and financial damage, and heightening fears of a severe economic downturn. Many states adopted extraordinary measures to fight the contagion, while companies shuttered stores and production, withdrew earnings guidance, and drew down credit lines at a record pace as borrowing costs soared. Volatility surged to extreme levels, and the S&P 500 Index suffered its fastest-ever decline into a bear market.

U.S. equities ended the second quarter of 2020 higher after an extraordinary rally drove U.S. equities to their largest quarterly gain since the fourth quarter of 1998. The unprecedented scale of the fiscal and monetary stimulus implemented by Congress and the U.S. Federal Reserve (Fed) in response to the pandemic was the most influential driver of the market’s rebound in the second quarter of 2020. Risk sentiment eased at the end of the second-quarter on concerns about a sharp rise in infections in some southern and western states, the rapid speed of the market’s rebound, and cautious economic-outlook comments from the Fed.

In the third-quarter of 2020, U.S. equities extended their strong rally, with markets bolstered by substantial monetary support from the Fed, a broadening U.S. economic recovery, better-than-expected corporate earnings, and promising trials for coronavirus vaccines. The U.S. economy gradually recovered during the third quarter; however, the path to a sustainable economic recovery was clouded by concerns about a resurgence in coronavirus infections in many areas of the country, an undetermined timeline for vaccines, high unemployment, elevated debt burdens, and uncertainty about additional fiscal stimulus. In September, the S&P 500 Index declined for the first time in five months. The Fed

In addition, Plug Power raised approximately $1 billion to execute and accelerate the first nation-wide green hydrogen network. Shares of Caleres, a footwear apparel company, fell during the period. Shares fell sharply in the first quarter of 2020 as a slowdown in retail demand throughout the U.S. in response to the coronavirus pandemic weighed on the stock price. Share prices partially recovered towards the end of the period. The company announced fiscal third quarter revenues and profits that beat expectations. We eliminated the Fund’s position in the stock during the period. Shares of Quidel rose following the U.S. Food & Drug Administration’s (FDA’s) authorization for the company’s rapid-result coronavirus tests.

Among the top contributors to relative performance during the period were an overweight position in Five9 (Information Technology), an overweight position in MyoKardia (Healthcare), and an overweight position in Cardlytics (Communication Services). Shares of Five9, a provider of cloud-based software for contact centers, ended the period higher. The stay-at-home economy as a result of the coronavirus pandemic benefited the stock price. MyoKardia shares rose during the period. The company announced in October 2020 that Bristol Myers Squibb will acquire the pharmaceutical firm for $13.1 billion. The acquisition was successfully completed in November 2020. Shares of Cardlytics, a purchase-intelligence technology company, ended the period higher. The company reported third-quarter results that beat revenue and earnings per share (EPS) consensus estimates, with declines that were not as bad as expected. Financial institution monthly active users grew 26%. Several sell-side analysts subsequently raised their price targets, pushing shares higher during the period.

Derivatives were not used in a significant manner in the Fund during the period and did not have a material impact on performance during the period.

What is the outlook as of the end of the period?

We are keeping an eye on the Georgia runoff elections for the Senate, waiting to see whether control of the Senate will flip to the Democrats. Depending on the outcome, we will consider various policy implications from that event, including if there is alignment of majorities for both legislative houses and the presidency.

It is encouraging that vaccinations have begun even if the pace of the initial rollout has been disappointing relative to earlier expectations. Despite worries about different strains, we remain optimistic so far about the potential for putting the pandemic behind us this year. Given the efficacy of the various vaccines, we are mindful that there still may be some lasting lifestyle changes. Despite that, we expect unemployment rates to come down in 2021 as a recovery takes hold, especially in some of the hardest-hit industries.

We remain cautious and mindful of pockets of extreme speculation and valuations that are hard to justify. On the positive side, we believe the combination of a high savings rate, stimulus payments, and rehiring more recently implies a very healthy consumer when the economic recovery takes shape.

As always, we continue to focus on the long term. While we did make some changes to the portfolio holdings in the Fund during the period, we continue to be incremental and mindful of the impact of volatility.

At the end of the period, the Fund’s largest overweights were to the Financials, Consumer Discretionary, and Consumer Staples sectors,

Average Annual Total Returns

for the Periods Ending 12/31/2020

PERFORMANCE DATA QUOTED REPRESENTS PAST PERFORMANCE AND DOES NOT GUARANTEE FUTURE RESULTS. The investment return and principal value of the investment will fluctuate so that investors’ shares, when redeemed, may be worth more or less than their original cost. The table and chart do not reflect the deductions of taxes, sales charges or other fees which may be applied at the variable contract level or by a qualified pension or retirement plan. Any such additional sales charges or other fees or expenses would lower the contract’s or plan’s performance. Current performance may be lower or higher than the performance data quoted. To obtain performance data current to the most recent month-end, please visit our website hartfordfunds.com.

Total returns presented above were calculated using the Fund’s net asset value available to shareholders for sale or redemption of Fund shares on 12/31/2020, which may exclude investment transactions as of this date. All share class returns assume the reinvestment of all distributions at net asset value and the deduction of all fund expenses.

Total returns for the report period presented in the table differs from the return in the Financial Highlights. The total return presented in the Financial Highlights section of the reports is calculated in the same manner, but also takes into account certain adjustments that are necessary under generally accepted accounting principles.

You cannot invest directly in an index.

See “Benchmark Glossary” for benchmark descriptions.

As shown in the Fund’s current prospectus, the total annual fund operating expense ratios for Class IA and Class IB were 0.79% and 1.04%, respectively. Gross and net expenses are the same. Actual expenses may be higher or lower. Please see the accompanying Financial Highlights for expense ratios for the period ended 12/31/2020.

Manager Discussion and Analysis

How did the Fund perform during the period?

The Class IA shares of Hartford Small Company HLS Fund returned 55.52% for the twelve-month period ended December 31, 2020, outperforming the Fund’s benchmark, the Russell 2000 Growth Index which returned 34.63% for the same period. For the same period, the Class IA shares of the Fund also outperformed the 36.91% average return of the Lipper Small-Cap Growth Funds peer group, a group of funds with investment strategies similar to those of the Fund.

Why did the Fund perform this way?

United States (U.S.) equities, as measured by the S&P 500 Index, posted positive results over the trailing twelve-month period ending December 31, 2020. During the first quarter of 2020, U.S. equities fell sharply after achieving record highs in February 2020, as the coronavirus spread rapidly throughout the country, causing unprecedented market disruptions and financial damage, and heightening fears of a severe economic downturn. During the second quarter of 2020, U.S. equities rallied to their largest quarterly gain since the fourth quarter of 1998. The unprecedented scale of the fiscal and monetary stimulus implemented by Congress and the U.S. Federal Reserve (Fed) in response to the pandemic was the most influential driver of the market’s rebound in the second quarter of 2020.

In the third quarter of 2020, U.S. equities extended their strong rally, with markets bolstered by substantial monetary support from the Fed, a broadening U.S. economic recovery, better-than-expected corporate earnings, and promising trials for coronavirus vaccines. The U.S. economy gradually recovered during the third quarter; however, the path to a sustainable economic recovery was clouded by concerns about a resurgence in coronavirus infections in many areas of the country, an undetermined timeline for vaccines, high unemployment, elevated debt burdens, and uncertainty about additional fiscal stimulus.

During the fourth quarter of 2020, U.S. equities rallied, bolstered by better-than-expected third-quarter 2020 earnings, economic resilience, substantial monetary support from the Fed, and optimism that vaccines would support a broad reopening of the U.S. economy in 2021. A sharp escalation in coronavirus infections across the country and renewed restrictions to curb the spread of the coronavirus were overshadowed by highly encouraging vaccine developments. Joe Biden was elected president, removing a key element of uncertainty for the market.

Returns during the period varied by market capitalization. Small-cap equities, as measured by the Russell 2000 Index, outperformed mid-cap

it will be expanding its hydrogen and fuel cell solutions for Walmart’s eCommerce applications. In addition, Plug Power raised approximately $1 billion to execute and accelerate the first nation-wide green hydrogen network. We initiated a position in the Fund late in the period but were underweight for most of 2020. Shares of Marriott Vacations fell early in the year after management reported fourth quarter 2019 revenue that was below expectations and meaningfully reduced full-year guidance as the pandemic’s global spread meaningfully weighed on hotel, leisure, and travel companies due to a sharp decrease in demand for their services. We exited the Fund’s position to fund better opportunities.

Derivatives were not used in a significant manner in the Fund during the period and did not have a material impact on performance during the period.

What is the outlook as of the end of the period?

As of the end of the period, we are seeking to maintain a good degree of balance, and not be overly reliant on any one scenario to play out. As the recovery continues to take shape, we have incrementally increased the Fund’s exposure to more cyclically-exposed companies that we believe stand to benefit as the economy re-opens.

At the end of the period, the Fund’s largest overweights were to the Consumer Discretionary, Financials, and Information Technology sectors, while the Fund’s largest underweights were to the Healthcare, Consumer Staples, and Real Estate sectors, relative to the Russell 2000 Growth Index.

Important Risks

Investing involves risk, including the possible loss of principal. Security prices fluctuate in value depending on general market and economic conditions and the prospects of individual companies. •Small-cap securities can have greater risks and volatility than large-cap securities. •Different investment styles may go in and out favor, which may cause the Fund to underperform the broader stock market. •Foreign investments may be more volatile and less liquid than U.S. investments and are subject to the risk of currency fluctuations and adverse political and economic developments. •The Fund’s focus on investments in particular sectors may increase its volatility and risk of loss if adverse developments occur.

Composition by Sector⁽¹⁾

as of 12/31/2020

Average Annual Total Returns

for the Periods Ending 12/31/2020

PERFORMANCE DATA QUOTED REPRESENTS PAST PERFORMANCE AND DOES NOT GUARANTEE FUTURE RESULTS. The investment return and principal value of the investment will fluctuate so that investors’ shares, when redeemed, may be worth more or less than their original cost. The table and chart do not reflect the deductions of taxes, sales charges or other fees which may be applied at the variable contract level or by a qualified pension or retirement plan. Any such additional sales charges or other fees or expenses would lower the contract’s or plan’s performance. Current performance may be lower or higher than the performance data quoted. To obtain performance data current to the most recent month-end, please visit our website hartfordfunds.com.

Total returns presented above were calculated using the Fund’s net asset value available to shareholders for sale or redemption of Fund shares on 12/31/2020, which may exclude investment transactions as of this date. All share class returns assume the reinvestment of all distributions at net asset value and the deduction of all fund expenses.

Total returns for the report period presented in the table differs from the return in the Financial Highlights. The total return presented in the Financial Highlights section of the reports is calculated in the same manner, but also takes into account certain adjustments that are necessary under generally accepted accounting principles.

You cannot invest directly in an index.

See “Benchmark Glossary” for benchmark descriptions.

As shown in the Fund’s current prospectus, the total annual fund operating expense ratios for Class IA and Class IB were 0.51% and 0.76%, respectively. Gross and net expenses are the same. Actual expenses may be higher or lower. Please see the accompanying Financial Highlights for expense ratios for the period ended 12/31/2020.

Manager Discussion and Analysis

How did the Fund perform during the period?

The Class IA shares of Hartford Stock HLS Fund returned 12.08% for the twelve-month period ended December 31, 2020, underperforming the Fund’s benchmark, the Russell 1000 Index, which returned 20.96% for the same period. For the same period, the Class IA shares of the Fund also underperformed the 17.29% average return of the Lipper Large-Cap Core Funds peer group, a group of funds with investment strategies similar to those of the Fund.

Why did the Fund perform this way?

United States (U.S.) equities, as measured by the S&P 500 Index, posted positive results over the trailing twelve-month period ended December 31, 2020. U.S. equities ended the first quarter of 2020 sharply lower after achieving record highs in February 2020, as the coronavirus spread rapidly throughout the country, causing unprecedented market disruptions and financial damage, and heightening fears of a severe economic downturn. Many states adopted extraordinary measures to fight the contagion, while companies shuttered stores and production, withdrew earnings guidance, and drew down credit lines at a record pace as borrowing costs soared. Volatility surged to extreme levels, and the S&P 500 Index suffered its fastest-ever decline into a bear market.

U.S. equities ended the second quarter of 2020 higher after an extraordinary rally drove U.S. equities to their largest quarterly gain since the fourth quarter of 1998. The unprecedented scale of the fiscal and monetary stimulus implemented by Congress and the U.S. Federal Reserve (Fed) in response to the pandemic was the most influential driver of the market’s rebound in the second quarter of 2020. Risk sentiment eased at the end of the second quarter on concerns about a sharp rise in infections in some southern and western states, the rapid speed of the market’s rebound, and cautious comments from the Fed regarding the economic outlook.

In the third quarter of 2020, U.S. equities extended their strong rally, with markets bolstered by substantial monetary support from the Fed, a broadening U.S. economic recovery, better-than-expected corporate earnings, and promising trials for coronavirus vaccines. The U.S. economy gradually recovered during the third quarter; however, the path to a sustainable economic recovery was clouded by concerns about a resurgence in coronavirus infections in many areas of the country, an undetermined timeline for vaccines, high unemployment, elevated debt burdens, and uncertainty about additional fiscal stimulus. In September, the S&P 500 Index declined for the first time in five months. The Fed signaled its expectation to hold interest rates near zero until inflation is on track to moderately exceed 2%.

During the fourth quarter of 2020, U.S. equities rallied, bolstered by better-than-expected third quarter earnings, economic resilience,

began to recover in the second half of 2020 as revenue growth returned and operating margins improved.

Top contributors to the Fund’s performance relative to the Russell 1000 Index during the period included Deere (Industrials), Danaher (Healthcare), and United Parcel Services (Industrials). Shares of Deere rose after the company announced strong third-quarter results, exceeding expectations. The agricultural machinery giant increased its sales outlook for the year as demand remained resilient despite the uncertainty related to the coronavirus pandemic. The company also announced the completion of the acquisition of Unimil, a leading Brazilian company in the aftermarket service parts business. Results for the fourth quarter of 2020 were strong as well, with operating margins increasing over the prior-year period. Management revised net income guidance upward for fiscal year 2021. Shares of Danaher, a manufacturer of scientific instruments and consumables, gained on earnings that beat consensus estimates throughout the year, driven by coronavirus-related demand. Operations at Cepheid and Cytiva boosted revenue in the second quarter of 2020, with Cytiva achieving organic revenue growth of 20%. In the third quarter of 2020, Cepheid’s core growth doubled year-over-year as it shipped seven million coronavirus test kits. UPS reported second- and third-quarter earnings well ahead of consensus estimates as the pandemic accelerated the broader shift to e-commerce sales for retailers. In the third quarter of 2020, international sales grew 17% on outbound Asia demand and higher cross-border shipments in Europe, while U.S. domestic package revenue rose 15% as solid business-to-consumer (B2C) package growth offset lower commercial business-to-business (B2B) deliveries.

Derivatives were not used in a significant manner in the Fund during the period and did not have a material impact on performance during the period.

What is the outlook as of the end of the period?

As of the end of the period, the data seems to support further market strength, but we believe this may not be the case. We believe there is dysfunction in Washington D.C., massive global debt, rising geopolitical risk, and a pandemic that will likely damage capacity for years to come. As such, we continue to seek to manage downside risk in the Fund. We think “upside” is a long-term concept and, therefore, more challenging to know. We believe “downside” is a short-term concept and, thus, more predictable. We tend to “think down” more than we “think up” because we believe that, over the long term, economies grow, markets go up and good companies get more valuable.

At the end of the period, the Fund’s largest overweights were in the Healthcare, Industrials, and Consumer Staples sectors, while the Fund’s largest underweights were in the Communication Services and Information Technology sectors, relative to the Russell 1000 Index.

Important Risks

Investing involves risk, including the possible loss of principal. Security prices fluctuate in value depending on general market and economic conditions and the prospects of individual companies. • For dividend-paying stocks, dividends are not guaranteed and may decrease without notice. • Foreign investments may be more volatile and less liquid than U.S. investments and are subject to the risk of currency fluctuations and adverse political and economic developments.

Average Annual Total Returns

for the Periods Ending 12/31/2020

PERFORMANCE DATA QUOTED REPRESENTS PAST PERFORMANCE AND DOES NOT GUARANTEE FUTURE RESULTS. The investment return and principal value of the investment will fluctuate so that investors’ shares, when redeemed, may be worth more or less than their original cost. The table and chart do not reflect the deductions of taxes, sales charges or other fees which may be applied at the variable contract level or by a qualified pension or retirement plan. Any such additional sales charges or other fees or expenses would lower the contract’s or plan’s performance. Current performance may be lower or higher than the performance data quoted. To obtain performance data current to the most recent month-end, please visit our website hartfordfunds.com.

Total returns presented above were calculated using the Fund’s net asset value available to shareholders for sale or redemption of Fund shares on 12/31/2020, which may exclude investment transactions as of this date. All share class returns assume the reinvestment of all distributions at net asset value and the deduction of all fund expenses.

Total returns for the report period presented in the table differs from the return in the Financial Highlights. The total return presented in the Financial Highlights section of the reports is calculated in the same manner, but also takes into account certain adjustments that are necessary under generally accepted accounting principles.

Performance information prior to 03/05/2012 represents performance of the Fund’s previous sub-adviser, Hartford Investment Management Company (“HIMCO”). As of 03/05/2012, HIMCO no longer served as the sub-adviser to the Fund.

You cannot invest directly in an index.

See “Benchmark Glossary” for benchmark descriptions.

Manager Discussion and Analysis

How did the Fund perform during the period?

The Class IA shares of Hartford Total Return Bond HLS Fund returned 9.03% for the twelve-month period ended December 31, 2020, outperforming the Fund’s benchmark, the Bloomberg Barclays U.S. Aggregate Bond Index, which returned 7.51% for the same period. For the same period, the Class IA shares of the Fund also outperformed the 8.11% average return of the Lipper Core Bond Funds peer group, a group of funds with investment strategies similar to those of the Fund.

Why did the Fund perform this way?

Most global fixed income sectors generated positive returns during the year. Sovereign yields declined sharply, particularly in the earlier part of 2020 at the onset of the coronavirus pandemic. Credit spreads widened in March 2020 over expectations that the decline in economic activity and supply chain disruptions would cause credit fundamentals to deteriorate. They later recouped most of their widening, helped by central bank policies, support from fiscal policy, and ultimately by encouraging vaccine developments. Through the rest of the year, equity market volatility remained elevated as markets oscillated between the negative effects of coronavirus containment measures and support provided by monetary and fiscal policy.

Global gross domestic product (GDP) releases indicated deep recessions in the second quarter of 2020 following various restrictions to business activity to combat the spread of the virus. By the end of the period, global GDP sharply rebounded as economies emerged from lockdowns and labor data showed signs of improvement. At the same time, front-end yields remained anchored with the prospect of continued accommodative central bank policy while long-end yields rose with the prospect of additional fiscal stimulus.

Global central banks maintained highly accommodative policy stances during the period. The Federal Reserve (Fed) provided additional assurance that asset buying would continue for the foreseeable future. The European Central Bank (ECB) extended its pandemic emergency purchase program through at least March 2022. The U.S. dollar weakened versus most currencies for the period.

Absolute returns were positive for most fixed-income sectors over the period, against a backdrop of accommodative central bank policies. On an excess return basis, lowest-rated sectors were among the worst performers, as were select sectors such as emerging market debt (EMD).

What is the outlook as of the end of the period?

As of the end of the period, we continue to position the Fund with a moderately pro-cyclical risk posture, consistent with our expectation for economic recovery supported by fiscal and monetary stimulus and vaccine distribution, while seeking to preserve liquidity. As of the end of the period, the Fund continued to be positioned for rising inflation expectations by maintaining an allocation to TIPS. While by year-end spreads across many fixed income sectors had recouped most of their widening experienced during March 2020, there are still sectors that we believe are priced wide relative to our expectations for excess returns over a one- to three-year time horizon.

We ended the period with an underweight positioning in the Fund to investment-grade credit in favor of holding an out-of-benchmark allocation to high yield and bank loans. The Fund held an overweight to agency MBS and maintained an out-of-benchmark exposure to select non-agency RMBS. The Fund also held high-quality CLOs and senior CMBS tranches with attractive collateral. As of the end of the period, the Fund continued to hold select exposure to EMD with a tilt toward higher-yielding issuers.

Important Risks

Investing involves risk, including the possible loss of principal. Security prices fluctuate in value depending on general market and economic conditions and the prospects of individual companies. The Fund may allocate a portion of its assets to specialist portfolio managers, which may not work as intended. •Fixed income security risks include credit, liquidity, call, duration, event, and interest-rate risk. As interest rates rise, bond prices generally fall. •The risks associated with mortgage-related and asset-backed securities as well as collateralized loan obligations (CLOs) include credit, interest-rate, prepayment, liquidity, default and extension risk. •The purchase of securities in the To-Be-Announced (TBA) market can result in additional price and counterparty risk. •Derivatives are generally more volatile and sensitive to changes in market or economic conditions than other securities; their risks include currency, leverage, liquidity, index, pricing, and counterparty risk. •Foreign investments may be more volatile and less liquid than U.S. investments and are subject to the risk of currency fluctuations and adverse political and economic developments. These risks may be greater for investments in emerging markets. •Investments in high-yield (“junk”) bonds involve greater risks of price volatility, illiquidity, and default than higher-rated debt securities. •Obligations of U.S. Government agencies are supported by varying degrees of credit but are generally not backed by the full faith and credit of the U.S. Government. •Restricted securities may be more difficult to sell and price than other securities.

Average Annual Total Returns

for the Periods Ending 12/31/2020

PERFORMANCE DATA QUOTED REPRESENTS PAST PERFORMANCE AND DOES NOT GUARANTEE FUTURE RESULTS. The investment return and principal value of the investment will fluctuate so that investors’ shares, when redeemed, may be worth more or less than their original cost. The table and chart do not reflect the deductions of taxes, sales charges or other fees which may be applied at the variable contract level or by a qualified pension or retirement plan. Any such additional sales charges or other fees or expenses would lower the contract’s or plan’s performance. Current performance may be lower or higher than the performance data quoted. To obtain performance data current to the most recent month-end, please visit our website hartfordfunds.com.

Total returns presented above were calculated using the Fund’s net asset value available to shareholders for sale or redemption of Fund shares on 12/31/2020, which may exclude investment transactions as of this date. All share class returns assume the reinvestment of all distributions at net asset value and the deduction of all fund expenses.

Total returns for the report period presented in the table differs from the return in the Financial Highlights. The total return presented in the Financial Highlights section of the reports is calculated in the same manner, but also takes into account certain adjustments that are necessary under generally accepted accounting principles.

Prior to 10/21/2013, the Fund was managed as a money market fund. Accordingly, performance of the Fund prior to 10/21/2013 is not shown. Past performance information for when the Fund was managed as a money market fund is available upon request by calling 1-888-843-7824.

Manager Discussion and Analysis

How did the Fund perform during the period?

The Class IA shares of Hartford Ultrashort Bond HLS Fund returned 1.44%, for the twelve-month period ended December 31, 2020, underperforming the Fund’s benchmark, the Bloomberg Barclays Short Treasury 9-12 Month Index, which returned 1.69% for the same period. For the same period, the Class IA shares of the Fund underperformed the 3.56% average return of the Lipper Short Investment Grade Debt Funds peer group, a group of funds that invest primarily in investment-grade issues with dollar-weighted average maturities of one to five years.

Why did the Fund perform this way?

Over the period, most global fixed-income markets generated positive total returns. Sovereign yields declined sharply, particularly in the earlier part of 2020 at the onset of the coronavirus pandemic. Credit spreads widened in March 2020 over expectations that the decline in economic activity and supply chain disruptions would cause credit fundamentals to deteriorate. They later recouped most of their widening, helped by central bank policies, support from fiscal policy, and ultimately by encouraging vaccine developments. Through the rest of the year, equity market volatility remained elevated as markets oscillated between the negative effects of coronavirus containment measures and support provided by monetary and fiscal policy.

Global gross domestic product (GDP) releases indicated deep recessions in the second quarter of 2020 following various restrictions to business activity to combat the spread of the virus. By the end of the period, global GDP sharply rebounded as economies emerged from lockdowns and labor data showed signs of improvement. At the same time, front-end yields remained anchored with the prospect of continued accommodative central bank policy while long-end yields rose with the prospect of additional fiscal stimulus.

Global central banks maintained highly accommodative policy stances during the period. The Federal Reserve (Fed) provided additional assurance that asset buying would continue for the foreseeable future. The European Central Bank (ECB) extended its pandemic emergency purchase program through at least March 2022. The U.S. dollar weakened versus most currencies for the period.

The primary detractor from the Fund’s relative performance versus the Bloomberg Barclays Short Treasury 9-12 Month Index during the period was the Fund’s duration/yield curve positioning. An underweight duration stance throughout the period had a negative impact on relative returns as front-end yields declined significantly. An out-of-benchmark allocation to investment-grade credit contributed positively to relative returns, particularly allocations to securities with issuers in the Financials and Industrials sectors. Despite spread widening in March 2020, the Fund’s investment-grade credit exposures generated positive excess returns. An allocation to consumer asset-backed securities (ABS) also benefited relative performance, as the ABS sector generated positive excess returns during the period.

Composition by Security Type⁽¹⁾

as of 12/31/2020

Bloomberg Barclays Government/Credit Bond Index (reflects no deduction for fees, expenses or taxes) measures the non-securitized component of the U.S. Aggregate Index. It includes investment grade, U.S. dollar-denominated, fixed-rate Treasuries, government-related and corporate securities.

Bloomberg Barclays Short Treasury 9-12 Month Index (reflects no deduction for fees, expenses or taxes) includes aged U.S. Treasury bills, notes and bonds with a remaining maturity from 1 up to (but not including) 12 months. It excludes zero coupon strips.

Bloomberg Barclays U.S. Aggregate Bond Index (reflects no deduction for fees, expenses or taxes) is composed of securities that are Securities and Exchange Commission registered, taxable, and dollar denominated. The index covers the U.S. investment grade fixed rate bond market, with index components for government and corporate securities, mortgage pass-through securities, and asset-backed securities. These major sectors are subdivided into more specific indices that are calculated and reported on a regular basis.

ICE BofA US 3-Month Treasury Bill Index (reflects no deduction for fees, expenses or taxes) is comprised of a single issue purchased at the beginning of the month and held for a full month. At the end of the month that issue is sold and rolled into a newly selected issue. The issue selected at each month-end rebalancing is the outstanding Treasury Bill that matures closest to, but not beyond, three months from the rebalancing date. To qualify for selection, an issue must have settled on or before the month-end rebalancing date.

MSCI All Country World (ACWI) ex USA Index (Net) (reflects reinvested dividends net of withholding taxes but reflects no deduction for fees, expenses or other taxes) is designed to capture large and mid cap representation across developed markets (excluding the United States) and emerging market countries.

Russell 1000 Index (reflects no deduction for fees, expenses or taxes) is designed to measure the performance of the 1,000 largest companies in the Russell 3000 Index which is designed to measure the performance of the 3,000 largest U.S. companies based on total market capitalizations.

Russell 3000 Index (reflects no deduction for fees, expenses or taxes) is designed to measure the performance of the 3,000 largest U.S. companies based on total market capitalization.

Russell 2000 Growth Index (reflects no deduction for fees, expenses or taxes) is designed to measure the performance of those Russell 2000 Index companies with higher price-to-book ratios and higher forecasted growth values. The Russell 2000 Index is an index comprised of 2,000 of the smallest U.S.-domiciled company common stocks based on a combination of their market capitalization and current index membership.

Russell 1000 Value Index (reflects no deduction for fees, expenses or taxes) is designed to measure the performance of those Russell 1000 Index companies with lower price-to-book ratios and lower forecasted growth values. The Russell 1000 Index is designed to measure the performance of the 1,000 largest companies in the Russell 3000 Index based on their market capitalization and current index membership.

S&P Composite 1500 Health Care Index (reflects no deduction for fees, expenses or taxes) is a float-adjusted market capitalization-weighted index comprised of those companies included in the S&P Composite 1500 that are classified as members of the Global Industry Classification Standard (GICS^®) health care sector.