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

Average Annual Total Returns

for the Periods Ending 12/31/19

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 chart and table 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 recentmonth-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 December 31, 2019, 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.

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 Balanced HLS Fund returned 22.80% for the twelve-month period ended December 31, 2019, outperforming the Fund’s custom benchmark, which is comprised of 60% S&P 500 Index, 35% Bloomberg Barclays Government/Credit Bond Index, and 5% ICE BofAML US3-Month Treasury Bill Index, which returned 22.20% for the same period. Individually, the S&P 500 Index, Bloomberg Barclays Government/Credit Bond Index, and ICE BofAML US3-Month Treasury Bill Index returned 31.49%, 9.71%, and 2.28%, respectively, during the period. For the same period, the Class IA shares of the Fund outperformed the 20.51% average return of the Lipper Mixed-Asset Target Allocation Growth Funds peer group, a group of funds that hold between60%-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, 2019. During the first quarter of 2019, U.S. equities rallied to their largest quarterly gain since 2009, buoyed by an accommodative shift in U.S. Federal Reserve (Fed) policy and guidance, optimism for a U.S.-China trade deal, relatively strong fourth-quarter 2018 earnings, and corporate buybacks. U.S. equity markets surged in the fourth quarter, as equities benefited from waning recession fears, improved trade sentiment, and accommodative Fed policies.

During the twelve-month period, all of the eleven sectors within the S&P 500 Index posted positive returns, led by the Information Technology (+50%), Communication Services (+33%), and Financials (+32%) sectors, while the Energy (+12%) and Healthcare (+21%) sectors lagged on a relative basis.

Over the period, global fixed-income markets generated largely positive total returns, driven by a decline in sovereign debt yields across most markets, particularly in the first three quarters of 2019. At the end of the period, yields increased across most markets amid stabilizing global activity indicators and progress on trade talks, despite continued accommodative global central bank policies. Geopolitical uncertainty remained elevated amid ongoing trade talks between the U.S. and China, negotiations surrounding the U.K.’s exit from the EU (also known as “Brexit”), and U.S. presidential impeachment proceedings. Despite these concerns, corporate bond spreads tightened over optimism that

from results relative to the S&P 500 Index, as the Fund did not hold the name earlier in the year. Shares of Tapestry, a luxury goods company formerly known as Coach, fell after the company missed on earnings and cut guidance early in the year, citing a volatile macroeconomic and geopolitical backdrop. In the second half of the year the stock was weighed down when the Kate Spade line did not return to sales growth as predicted, prompting the company to pull back on store openings for the brand. TD Ameritrade (Financials), Nektar Therapeutics (Healthcare), and Tapestry (Consumer Discretionary) were the top detractors from absolute returns during the period.

Top contributors to performance relative to the S&P 500 Index in the equity portion of the Fund during the period included KLA (Information Technology), Qualcomm (Information Technology), and Fortune Brands Home (Industrials). Shares of KLA, a semiconductor equipment company, traded higher on strong earnings and an upward revision in guidance. Some analysts see profit increasing due to advanced chips for 5G smartphones and artificial intelligence devices boosting demand for KLA’s chip-inspection equipment in the next few years. The stock also benefited from secular tailwinds from expectations around improved memory-chip prices and a return to growth for the industry. Shares of Qualcomm jumped early in the year after announcing it had reached a settlement with Apple ending a long-running legal dispute over royalty payments. In the fourth quarter of 2019, the company raised guidance on expectations of increased demand for its 5G technology as the market continues to accelerate. Shares of Fortune Brands Home, a U.S.-based provider of home and security products, rose after the stock was upgraded by some analysts on the outlook that exposure to repair and remodeling may offset concerns about a cyclical peak in homebuilding. Microsoft (Information Technology), Alphabet (Communication Services), and JPMorgan Chase (Financials) were the top contributors to absolute returns during the period.

The fixed income portion of the Fund outperformed the Bloomberg Barclays Government/Credit Bond Index during the period. Security selection within investment-grade credit was the largest contributor to outperformance relative to the Bloomberg Barclays Government/Credit Bond Index, particularly selection within the Industrials, Financials and Taxable Municipals sectors. An overweight to investment-grade credit was a modestly positive contributor overall, as positive impacts from an overweight to the Financials and Taxable Municipals sectors were largely offset by a negative impact from an underweight to the Industrials and Sovereign Bonds.Out-of-benchmark allocations to securitized sectors such as agency mortgage-backed securities (MBS) pass-throughs, collateralized loan obligations (CLOs),non-agency mortgage backed securities (NA MBS), and commercial mortgage-backed securities (CMBS) all contributed positively to performance. Duration/yield curve positioning contributed modestly over the period, particularly long positioning in the intermediate region of the yield curve. A modestout-of-benchmark allocation to Treasury Inflation-Protected Securities (TIPS) also contributed positively to performance.

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 U.S. economy grew 2.1% in the third quarter of 2019, with healthy consumer spending serving as the key driver of economic growth. The labor market remained strong, with job growth consistently exceeding

and extension risk.•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.

Composition by Security Type⁽¹⁾

as of December 31, 2019

Average Annual Total Returns

for the Periods Ending 12/31/19

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 chart and table 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 recentmonth-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 December 31, 2019, 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.

Class IC shares commenced operations on April 30, 2014. Class IC shares performance prior to that date reflects Class IA shares performance adjusted to reflect the12b-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.

As shown in the Fund’s current prospectus, the total annual fund operating expense ratios for Class IA, Class IB and Class IC were 0.67%, 0.92% and 1.17%, respectively. Gross and net

Manager Discussion and Analysis

How did the Fund perform during the period?

The Class IA shares of Hartford Capital Appreciation HLS Fund returned 31.28% for the twelve-month period ended December 31, 2019, outperforming one of its benchmarks, the Russell 3000 Index, which returned 31.02% for the same period. For the same period, Class IA shares of the Fund underperformed its other benchmark, the S&P 500 Index, which returned 31.49% for the same period. For the same period, the Class IA shares of the Fund outperformed the 28.15% average return of the LipperMulti-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, 2019. During the first quarter of 2019, U.S. equities rallied to their largest quarterly gain since 2009, buoyed by an accommodative shift in U.S. Federal Reserve (Fed) policy and guidance, optimism for a U.S.-China trade deal, relatively strong fourth-quarter 2018 earnings, and corporate buybacks. By the summer of 2019, unresolved trade tensions between the U.S. and its trading partners unsettled markets and raised concerns about the potential risks to U.S. economic growth from increasing cost pressures, supply chain disruptions, and waning business confidence and investment plans. In the third quarter of 2019, U.S. equities rose for the third consecutive quarter, as the U.S. economy remained resilient despite elevated geopolitical uncertainties and slowing global growth. The Fed lowered its benchmark interest rate in July and September by a combined 0.50% in an effort to sustain the U.S. economic expansion and mitigate the risks of moderating growth and trade frictions. U.S. equity markets surged in the fourth quarter of 2019, as equities benefited from waning recession fears, improved trade sentiment, and accommodative Fed policies. In October, the Fed lowered interest rates for the final time in 2019, cutting rates by 0.25%. Trade tensions continued to be volatile during the fourth quarter of 2019, but eased in December after the U.S. and China reached a phase one trade agreement.

Returns varied by market cap during the period, aslarge-cap equities, as measured by the S&P 500 Index, outperformed both small- andmid-cap equities, as measured by the Russell 2000 Index and S&P MidCap 400 Index, respectively. All eleven sectors in the Russell 3000 Index had positive returns during the period. The Information Technology (+49%), Communication Services (+32%), and Financials (+31%) sectors were the top performers, while the Energy (+10), Healthcare (+22%), and Materials (+24%) sectors lagged on a relative basis.

results which drove the stock price down. As of the end of the period, the Fund continued to own the stock. 2U (Information Technology) and Pinterest (Communication Services) were among the top absolute detractors from performance during the period.

The largest contributors during the period to performance relative to the Russell 3000 Index were CoStar Group (Industrials), lack of exposure to Berkshire Hathaway (Financials), and Advanced Micro Devices (Information Technology). Costar Group is a provider of data and analytics for the commercial real estate industry. Shares of the company trended higher throughout the year as the company consistently met or exceeded market expectations for quarterly results during the year. We reduced the Fund’s exposure during the period; however, we still believe the stock is well positioned to benefit from continued positive company-specific and macro conditions. Berkshire Hathaway is a diversified company operating in property and casualty insurance and reinsurance, utilities and energy, freight rail transportation, finance, manufacturing, retailing, and services. Not holding the stock contributed positively to performance as the share price moved higher during the period but underperformed relative to the broader market. As of the end of the period, the Fund did not hold the stock. Advanced Micro Devices, a semiconductor manufacturer, reported strong results throughout the period that were in line with consensus estimates. Results were driven by strong sales of new client and server CPU business in addition to benefiting from a recovering gaming GPU market. As of the end of the period, the Fund continued to hold the stock. American Tower (Real Estate) and Microsoft (Information Technology) were among the top absolute contributors during the period.

During the period, the Fund, at times, uses 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 did not have a significant impact on performance, while the use of equity index futures contributed modestly to results.

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

At the end of the period, macro challenges created a volatile backdrop for the market in 2019, and we expect this to persist into the new year. We note an unusual lack of consensus across the industry around the macroeconomic outlook as of the end of the period, which leads to a wide range of potential outcomes from our perspective. As a result, we seek to balance the Fund’s risk allocations in an effort to guard against a possible downturn without giving up the potential for participating in the event of a market reacceleration. In our capital allocation framework, we seek to balance risk factor exposure in the Fund by allocating to underlying managers with varying investment styles, but all of whom focus on growth of capital as an objective.

In addition to persistent market volatility, we believe there could also be persistence in the factor volatility that we saw in 2019. We monitor the portfolio for meaningful changes in risk characteristics and seek to actively manage allocations with respect to a changing risk landscape. To that end, we seek to balance risk relative to various potential market outcomes.

At the end of the period, the Fund’s largest overweights were to the Healthcare and Industrials sectors, while the Fund’s largest underweights were to the Information Technology and Financials sectors, relative to the Russell 3000 Index.

Average Annual Total Returns

for the Periods Ending 12/31/19

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 chart and table 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 recentmonth-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 December 31, 2019, 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.

You cannot invest directly in an index.

See “Benchmark Glossary” for benchmark descriptions.

As shown in the Fund’s prospectus dated May 1, 2019, the total annual fund operating expense ratios for Class IA and Class IB were 0.78% and 1.03%, respectively. The Fund filed a supplement to its prospectus, dated November 27, 2019, with the U.S. Securities and Exchange Commission that updated the Fund’s total annual fund operating expense table effective January 1, 2020. However, the information in this annual report is as of December 31, 2019 and does not reflect any changes made to the total annual fund operating expense table in the prospectus, as supplemented. The total annual fund

Manager Discussion and Analysis

How did the Fund perform during the period?

The Class IA shares of Hartford Disciplined Equity HLS Fund returned 34.12% for the twelve-month period ended December 31, 2019, outperforming its benchmark, the S&P 500 Index, which returned 31.49% for the same period. For the same period, the Class IA shares of the Fund also outperformed the 29.61% average return of the LipperLarge-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 ending December 31, 2019. During the first quarter of 2019, U.S. equities rallied to their largest quarterly gain since 2009, buoyed by an accommodative shift in U.S. Federal Reserve (Fed) policy and guidance, optimism for a U.S.-China trade deal, relatively strong fourth-quarter 2018 earnings, and corporate buybacks. By the summer of 2019, unresolved U.S. trade frictions with China, Mexico, Japan, and the European Union (EU) unsettled markets and raised concerns about the potential risks to U.S. economic growth from increasing cost pressures, supply chain disruptions, and waning business confidence and investment plans. In the third quarter of 2019, U.S. equities rose for the third consecutive quarter, with the U.S. economy remaining resilient despite elevated geopolitical uncertainties and slowing global growth. U.S.-China trade relations were particularly volatile in the absence of meaningful compromises on key structural issues. Expectations for a protracted trade war and the potential for a longer-term decoupling of the world’s two largest economies eroded consumer and business confidence and curtailed capital spending. The Fed lowered its benchmark interest rate in July and September by a combined 0.50% in an effort to sustain the U.S. economic expansion and mitigate the risks of moderating growth and trade frictions. U.S. equity markets surged in the fourth quarter of 2019, as equities benefited from waning recession fears, improved trade sentiment, and accommodative Fed policies. In October, the Fed lowered interest rates for the final time in 2019, cutting rates by 0.25%. Trade tensions were volatile during the fourth quarter of 2019 but eased in December after the U.S. and China reached a phase one trade agreement. The U.S. House of Representatives voted to impeach President Trump; however, markets were unaffected given that theRepublican-led Senate is unlikely to support his impeachment.

among the top detractors from relative performance. Shares of the company underperformed after a slowdown in growth in the company’s web hosting business and a CEO transition. Shares of NetApp declined during the period after the company announced disappointing first-quarter fiscal year results and revised its previously issued guidance for full year 2020. NetApp was the top absolute detractor during the period, and we eliminated the Fund’s position.

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 we look ahead to 2020, many of the constructive fundamental drivers of U.S. economic growth in 2019 persist. We believe labor markets remain healthy, and wage gains continue to bolster consumer confidence, but may not trigger outsized inflation due to continued productivity improvements. In our view, the U.S. housing market has turned the corner after six quarters of negative growth, responding to rate cuts by the Fed. Moving forward, Fed action is likely to be more gradual, having now achieved targeted levels of inflation. This may also result in less volatility for the U.S. dollar.

We believe trade negotiations between the U.S. and China will remain vitally important to markets. In our view, the year ended with encouraging progress; the “List 4” tariffs slated for December implementation were delayed, and indications that forward progress for a phase one agreement were in place. Additionally, the U.S. House of Representatives passed thetri-party United States-Mexico-Canada Agreement (USMCA), a replacement for the North American Free Trade Agreement (NAFTA), which is expected to be ratified by the U.S. Senate. The ratification of this trade agreement is expected to provide important certainty to North American supply chains. As the new year begins, we believe that U.S. politics will first be dominated by a historic presidential impeachment trial in the U.S. Senate, before yielding to a rapid succession of Democratic primaries which will provide more certainty into both the eventual Democratic candidate as well as the main platform issues to be put forward by that party in the presidential election. The outcome at the ballot box could warrant future action in the Fund, but given the wide range of possible outcomes at this point, we believe that this bears more monitoring than action at this time.

At the end of the period, the Fund’s largest overweights relative to the S&P 500 Index were to the Healthcare, Consumer Staples, and Industrials sectors, while the Fund’s largest underweights relative to the S&P 500 Index were to the Communication Services, Energy, and Information Technology sectors.

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.

Average Annual Total Returns

for the Periods Ending 12/31/19

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 chart and table 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 recentmonth-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 December 31, 2019, 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.

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 0.68% and 0.93%, 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 December 31, 2019.

The Fund is closed to certain qualified pension and retirement plans. For more information, please see the Fund’s statutory prospectus.

Manager Discussion and Analysis

How did the Fund perform during the period?

The Class IA shares of Hartford Dividend and Growth HLS Fund returned 28.60% for the twelve-month period ended December 31, 2019, underperforming one of its benchmarks, the S&P 500 Index, which returned 31.49% for the same period. For the same period, Class IA shares of the Fund outperformed its other benchmark, the Russell 1000 Value Index, which returned 26.54% for the same period. For the same period, the Class IA shares of the Fund outperformed the 24.43% 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 ending December 31, 2019. During the first quarter of 2019, U.S. equities rallied to their largest quarterly gain since 2009, buoyed by an accommodative shift in U.S. Federal Reserve (Fed) policy and guidance, optimism for a U.S.-China trade deal, relatively strong fourth-quarter 2018 earnings, and corporate buybacks. By the summer of 2019, unresolved U.S. trade frictions with China, Mexico, Japan, and the European Union (EU) unsettled markets and raised concerns about the potential risks to U.S. economic growth from increasing cost pressures, supply chain disruptions, and waning business confidence and investment plans. In the third quarter of 2019, U.S. equities rose for the third consecutive quarter, with the U.S. economy remaining resilient despite elevated geopolitical uncertainties and slowing global growth. U.S.-China trade relations were particularly volatile in the absence of meaningful compromises on key structural issues. Expectations for a protracted trade war between the U.S. and China and the potential for a longer-term decoupling of the world’s two largest economies eroded consumer and business confidence and curtailed capital spending. The Fed lowered its benchmark interest rate in July and September by a combined 0.50% in an effort to sustain economic expansion and mitigate the risks of moderating growth and trade frictions. U.S. equity markets surged in the fourth quarter of 2019, as equities benefited from waning recession fears, improved trade sentiment, and accommodative Fed

outlook, Verizon’s stock price faltered during the period as net customer additions were a bit weaker than anticipated. Pfizer’s share price declined after the company announced its Upjohn business merger with Mylan.

Top contributors to performance relative to the S&P 500 Index over the period included overweight allocations to Hess (Energy) and KLA (Information Technology), as well as not holding benchmark constituent Berkshire Hathaway (Financials). Hess traded well due to higher oil prices over the period, and we believe the company remains well positioned over the next several years due to its significant oil discovery in Guyana. KLA continued to outperform its semiconductor equipment peer group with strong fourth-quarter 2019 earnings and guidance for September that beat consensus expectations. The Fund’s overweight position in KLA also contributed positively to relative performance during the period. Not holding Berkshire Hathaway contributed positively to performance as the share price moved higher during the period but underperformed relative to the broader market. As of the end of the period, we do not hold Berkshire Hathaway in the Fund.

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?

Despite much volatility and changes in market leadership throughout 2019, the combination of stabilizing economic data, accommodative central banks, and continued optimism around an eventual trade deal between the U.S. and China provided a favorable backdrop for equities. We expect that 2020 will be somewhat more challenging for robust stock returns due to higher valuations at the start of the year, limited room for further easing by central banks, and the many uncertainties related to geopolitics.

Notably, the consumer was particularly strong in 2019 as low unemployment, tax rebates, and solid spending helped propel the economy forward. While we believe the economy will still benefit from strong consumer support, it will likely be less significant. We are enthusiastic about the prospects for many individual businesses.

At the end of the period, the Fund’s largest overweights relative to the S&P 500 Index were to the Financials, Energy, and Healthcare sectors, while the Fund’s largest underweights were to the Information Technology and Consumer Discretionary sectors.

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 12/31/19

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 chart and table 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 recentmonth-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 December 31, 2019, 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.

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 0.80% and 1.05%, 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 December 31, 2019.

The Fund is closed to certain qualified pension and retirement plans. For more information, please see the Fund’s statutory prospectus.

Manager Discussion and Analysis

How did the Fund perform during the period?

The Class IA shares of Hartford Global Growth HLS Fund returned 32.61% for the twelve-month period ended December 31, 2019, underperforming its benchmark, the MSCI World Growth Index (Net), which returned 33.68% for the same period. For the same period, the Class IA shares of the Fund outperformed the 29.19% average return of the Lipper GlobalMulti-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?

For the twelve-month period ended December 31, 2019, global equities rose more than 26.6% as measured by the MSCI ACWI Index. In the first quarter of 2019, global markets recovered and surged due to productive trade negotiations between the U.S. and China, and due to accommodative rhetoric and policy actions from the major central banks. In the second quarter of 2019, global equities rose for the second straight quarter. Trade tensions between China and the U.S. escalated in May but eased at the end of the quarter after the two countries agreed to resume trade negotiations at the G20 summit. The United Kingdom’s (U.K.’s) exit from the European Union (EU), also known as Brexit, was a major concern, with the U.K. avoiding an abruptno-deal departure after the EU leaders granted the U.K. a flexible extension. U.K. Prime Minister Theresa May announced that she would resign after failing to secure a Brexit deal. In the third quarter of 2019, Boris Johnson was appointed as the new prime minister of the U.K. after his victory in the Conservative Party leadership contest. U.K. opposition parties vowed to block Prime Minister Johnson’s bid for a general election and Parliament passed legislation requiring him to request an additional extension to the Brexit process if he failed to secure an acceptable deal. On the monetary front, the U.S. Federal Reserve (Fed) cut interest rates in July, September, and October to extend the U.S. economic expansion amid a slowdown in growth and trade uncertainty. The European Central Bank (ECB) unveiled a sweeping, long-term economic stimulus package to bolster the Eurozone economy against slowing growth and trade frictions, including an open-ended asset purchase program and more favorable bank lending conditions. In the fourth quarter, waning recession fears and forecasts for improving global growth in 2020 helped to bolster risk sentiment, while geopolitics and trade disputes continued to be major drivers of market volatility. The U.S. canceled tariffs that were scheduled to take effect in an effort to secure a phase one trade deal with China. U.K. equities rose after the Conservative Party’s victory in the general election lifted the uncertainty about the country’s departure from the EU and eliminated concerns about the Labor Party’s plans to nationalize large swaths of the nation’s economy.

rising demand for next generation technologies, such as connected consumer products and 5G internet. Microsoft (Information Technology) was a top absolute contributor to Fund 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?

Looking ahead, we expect that our focus will remain on stock selection driven bybottom-up, fundamental research, regular meetings with the management of leading companies globally, and leveraging the deep research capabilities of our firm. However, we believe that risks remain on the horizon, including the upcoming U.S. elections, trade negotiations between the U.S. and China, and increased geopolitical tensions globally. We remain focused on seeking companies with improving fundamentals and catalysts that we think should lead to accelerating earnings growth above consensus expectations.

At the end of the period, the Fund’s largest sector overweights were to the Information Technology, Communication Services, and Financials sectors, while the Fund’s largest underweights were to the Industrials, Healthcare and Materials sectors, relative to the MSCI World Growth Index (Net).

Important Risks

Investing involves risk, including the possible loss of principal. The Fund seeks to achieve its investment objective by allocating assets among different portfolio management teams. Security prices fluctuate in value depending on general market and economic conditions and the prospects of individual companies.•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.•Mid-cap securities can have greater risk and volatility thanlarge-cap securities.•Different investment styles may go in and out of favor, which may cause the Fund to underperform the broader stock market.

Average Annual Total Returns

for the Periods Ending 12/31/19

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 chart and table 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 recentmonth-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 December 31, 2019, 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.

Class IC shares commenced operations on April 30, 2014. Class IC shares performance prior to that date reflects Class IA shares performance adjusted to reflect the12b-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.

As shown in the Fund’s current prospectus, the total annual fund operating expense ratios for Class IA, Class IB and Class IC were 0.65%, 0.90% and 1.15%, respectively. Gross and net

Manager Discussion and Analysis

How did the Fund perform during the period?

The Class IA shares of Hartford Growth Opportunities HLS Fund returned 30.68% for the twelve-month period ended December 31, 2019, underperforming its benchmarks, the Russell 3000 Growth Index and the Russell 1000 Growth Index, which returned 35.85% and 36.39%, respectively, for the same period. For the same period, the Class IA shares of the Fund also underperformed the 31.17% average return of the LipperMulti-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, 2019. During the first quarter of 2019, U.S. equities rallied to their largest quarterly gain since 2009, buoyed by an accommodative shift in U.S. Federal Reserve (Fed) policy and guidance, optimism for a U.S.-China trade deal, relatively strong fourth-quarter 2018 earnings, and corporate buybacks. By the summer of 2019, unresolved U.S. trade frictions with China, Mexico, Japan, and the European Union (EU) unsettled markets and raised concerns about the potential risks to U.S. economic growth from increasing cost pressures, supply chain disruptions, and waning business confidence and investment plans. In the third quarter of 2019, U.S. equities rose for the third consecutive quarter, with the U.S. economy remaining resilient despite elevated geopolitical uncertainties and slowing global growth. U.S.-China trade relations were particularly volatile in the absence of meaningful compromises on key structural issues. Expectations for a protracted trade war between the U.S. and China and the potential for a longer-term decoupling of the world’s two largest economies eroded consumer and business confidence and curtailed capital spending. The Fed lowered its benchmark interest rate in July and September by a combined 0.50% in an effort to sustain the U.S. economic expansion and mitigate the risks of moderating growth and trade frictions. U.S. equity markets surged in the fourth quarter of 2019, as equities benefited from waning recession fears, improved trade sentiment, and accommodative Fed policies. In October, the Fed lowered interest rates for the final time in 2019, cutting rates by 0.25%. Trade tensions were volatile during most of the fourth quarter of 2019 but eased in December after the U.S. and China reached a phase one trade agreement. The U.S. House of Representatives voted to impeach President Trump; however, markets were unaffected given that theRepublican-led Senate is unlikely to support his impeachment.

stronger–than-expected third-quarter 2019 results, beating consensus estimates. Furthermore, Insulet gained Federal Drug Administration (FDA) approval for the use of Novo Nordisk’s Fiasp, a fast-acting insulin. Shares of Advanced Micro Devices (AMD), a semiconductor company, rose towards the end of the period after Microsoft unveiled several new Surface laptops using AMD CPU chips. This was viewed by investors as a positive for AMD’s latest CPUs and its competitive positioning against its competitor, Intel. The company also benefited from the announcement of a phase one trade deal between the U.S. and China. Shares of Shopify, a global commerce company, rose during the period. The company reported better-than-expected results driven by international expansion and increased its 2019 income forecast guidance. Amazon (Consumer Discretionary) was a top absolute contributor to performance.

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?

Looking ahead, we have a slightly more positive outlook from a macro standpoint as we begin 2020. We believe U.S. economic fundamentals remain solid, and we believe valuations are reasonable. U.S.-China trade tensions have eased, and, barring anyre-escalation or additional tariffs, we believe growth may resume. Though the upcoming U.S. election creates some uncertainty, the chances of a morepro-market outcome have increased. Across the Fund, we seek to take a balanced view and weigh potential risk and reward.

At the end of the period, ourbottom-up investment approach resulted in the Fund’s overweight exposures to the Consumer Discretionary, Healthcare, and Financials sectors, relative to the Russell 3000 Growth Index. The Fund’s largest underweights relative to the Russell 3000 Growth Index were to the Information Technology, Consumer Staples, and Real Estate sectors, at the end of the period.

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.•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.•Mid-cap securities can have greater risk and volatility thanlarge-cap securities.•The Fund’s focus on investments in particular sectors may increase its volatility and risk of loss if adverse developments occur.•Different investment styles may go in and out favor, which may cause the Fund to underperform the broader stock market.

Average Annual Total Returns

for the Periods Ending 12/31/19

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 chart and table 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 recentmonth-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 December 31, 2019, 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.

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 0.89% and 1.14%, 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 December 31, 2019.

The Fund is closed to certain qualified pension and retirement plans. For more information, please see the Fund’s statutory prospectus.

Manager Discussion and Analysis

How did the Fund perform during the period?

The Class IA shares of Hartford Healthcare HLS Fund returned 33.95% for the twelve-month period ended December 31, 2019, outperforming the Fund’s benchmarks, the S&P Composite 1500 Health Care Index, which returned 20.87%, and the S&P 500 Index, which returned 31.49%, for the same period. For the same period, the Class IA shares of the Fund outperformed the 26.24% 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?

U.S. healthcare equities (+21%) underperformed the broader U.S. equity market (+31%) and global equity market (+28%) during the period, as measured by the S&P Composite 1500 Healthcare Index, S&P 500 Index, and the MSCI World Index, respectively. Within the S&P Composite 1500 Health Care Index, the Medical Technology sector returned +29%, the Healthcare Services sector returned +21%, theLarge-cap Biopharma sector returned +16%, theMid-cap Biopharma sector returned +9%, and theSmall-cap Biopharma sector returned-5%.

The Fund outperformed the S&P Composite 1500 Health Care Index over the period due primarily to favorable security selection decisions. Security selection was strongest in the Small- andMid-cap Biopharma sectors. Sector allocation detracted from performance relative to the S&P Composite 1500 Health Care Index during the period. An overweight to the Small- andMid-cap Biopharma sectors detracted from relative results during the period, more than offsetting positive results from an underweight to theLarge-cap Biopharma sector.

Medicines Co.(Mid-cap Biopharma), Seattle Genetics(Mid-cap Biopharma), and Loxo Oncology(Mid-cap Biopharma) were the top contributors to performance relative to the S&P Composite 1500 Health Care Index during the period. Medicines Co. and Novartis announced an agreement in which Novartis would acquire Medicines Co. for $9.7 billion, or $85 per share, reflecting a 41% premium to the stock’s30-day volume weighted average price prior to the announcement. Upon this news, we eliminated the position to take profits. Seattle Genetics is a biopharmaceutical company that develops monoclonal antibody-based targeted therapies for the treatment of cancer and autoimmune diseases. Shares outperformed over the period, most notably driven by positive trial results of the drug tucatinib, which met the primary endpoint of progression-free survival in treating patients with certain types of

for All” has little chance of becoming law regardless of the outcome of the 2020 elections. As for drug pricing, the biotech and pharma industry groups have stated that they would willingly relinquish some of their profits in order to reduce patientout-of-pocket drug costs and thus hopefully avoid the worst-case outcome of drug price-setting by the government. Whether any drug pricing legislation or regulation comes to pass remains to be seen, as politicians in Washington D.C. are currently preoccupied with other issues in our view.

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 believe that innovation, an aging population, and the globalization of demand for cutting-edge Western-style medicines may 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.•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.•Small- andmid-cap securities can have greater risk and volatility thanlarge-cap securities.

Composition by Subsector⁽¹⁾

as of December 31, 2019

Average Annual Total Returns

for the Periods Ending 12/31/19

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 chart and table 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 recentmonth-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 December 31, 2019, 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.

Performance information prior to March 5, 2012 represents performance of the Fund’s previoussub-adviser, Hartford Investment Management Company (“HIMCO”). As of March 5, 2012 HIMCO no longer served as thesub-adviser to the Fund.

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 0.78% and 1.03%, 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 December 31, 2019.

Manager Discussion and Analysis

How did the Fund perform during the period?

The Class IA shares of Hartford High Yield HLS Fund returned 15.06% for the twelve-month period ended December 31, 2019, outperforming its benchmark, the Bloomberg Barclays U.S. Corporate High Yield Index, which returned 14.32% for the same period. For the same period, the Class IA shares of the Fund outperformed the 13.65% average return of the Lipper High Yield Funds peer group, a group of funds with investment strategies similar to those of the Fund.

Why did the Fund perform this way?

Over the period, global fixed-income markets generated largely positive total returns, driven by a decline in sovereign debt yields across most markets – particularly in the first three quarters of 2019. By the end of the period, yields increased across most markets amid stabilizing global activity indicators and progress on trade talks, despite continued accommodative global central bank policies. Geopolitical uncertainty remained elevated amid ongoing trade talks between the United States (U.S.) and China, negotiations surrounding the United Kingdom’s (U.K.’s) exit from the European Union (EU), also known as “Brexit”, and U.S. presidential impeachment proceedings. Despite these concerns, corporate bond spreads tightened due to optimism that monetary accommodation could offset the drag on global growth from restrictive trade policies. The U.S. dollar cemented its safe-haven status, strengthening versus most currencies amid trade frictions and slowing global growth prospects. Inflation showed no meaningful acceleration even as wage growth edged higher.

Global monetary policies continued along a more accommodative path, in aggregate. The U.S. Federal Reserve (Fed) cut interest rates three times before deciding to take a more patient approach on future adjustments. Meanwhile, the European Central Bank (ECB) launched a package of stimulus measures, including an interest rate cut, resumption of asset purchases that the central bank plans to continue “as long as necessary,” and the introduction of tiered deposit rates to exempt banks from negative interest rates. The Bank of Japan (BoJ) maintained its short-term negative interest rate policy, while pledging to guide10-year government bonds to around 0.0%. The Norges Bank, an outlier among major central banks this year, increased interest rates three times but trimmed the projected path for interest rate increases, citing global uncertainties.

For much of 2019, sovereign debt yields fell due to global economic uncertainty, accommodative shifts by central banks, and escalating trade tensions. However, yields began to increase as U.S.-China trade tensions softened later in the year. A flight to safe-haven assets earlier in the year – in addition to accommodative Fed policy – led to a decline in U.S. yields. As German bund yields fell to record lows over the year – and the entire German yield curve fell into negative territory by August – investors seeking yield put their money to work in the U.S. Persistent Brexit uncertainty contributed positively to lower yields in the U.K., while

currency risk from investments innon-dollar-denominated securities. Although we typically view currency forwards in conjunction with the securities intended to be hedged, on a standalone basis the currency forwards contributed positively to performance relative to the Bloomberg Barclays U.S. Corporate High Yield Index over the period.

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

We expect range-bound high-yield spreads in 2020 with pockets of volatility presenting attractive opportunities in our view. We assign a low probability of U.S. and euro area recession in 2020, but the longer-term macro outlook remains unclear. We believe that issuer fundamentals across high-yield issuers remain solid overall as of the end of the period, but have been weakening modestly. We view spreads onCCC-rated debt as attractive and believe selectively increasing exposure to CCC rated issuers with improving credit profiles is prudent. While we believe selectively owning CCC rated bonds presents good total return opportunities, we also expect bouts of spread widening around developments on the U.S. presidential campaign, Brexit, Italian politics, and emerging markets growth that we believe will present attractive investment opportunities. We favor the Gaming sector due to favorable consumer trends and low expected supply growth; however, we remain cautious on the Retail sector, which suffers from secular decline, asbrick-and-mortar stores continue to lose market share toe-commerce companies.

The Fund ended the period with the largest overweights to the Technology and Gaming sectors and the largest underweights to the Retail and Media and Entertainment sectors. From a credit quality perspective, the Fund was overweight B rated and underweight BB rated and CCC and below-rated securities.

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.•Fixed income security risks include credit, liquidity, call, duration, and interest-rate risk. As interest rates rise, bond prices generally fall.•Investments in high-yield (“junk”) bonds involve greater risk of price volatility, illiquidity, and default than higher-rated debt securities.•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.•Restricted securities may be more difficult to sell and price than other securities.

Average Annual Total Returns

for the Periods Ending 12/31/19

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 chart and table 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 recentmonth-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 December 31, 2019, 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.

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 0.73% and 0.98%, 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 December 31, 2019.

The Fund is closed to certain qualified pension and retirement plans. For more information, please see the Fund’s statutory prospectus.

Manager Discussion and Analysis

How did the Fund perform during the period?

The Class IA of the Hartford International Opportunities HLS Fund returned 26.43% for the twelve-month period ended December 31, 2019, outperforming its benchmark, the MSCI All Country World (ACWI) ex USA Index (Net), which returned 21.51% for the same period. For the same period, the Class IA shares of the Fund underperformed the 26.82% average return of the Lipper InternationalLarge-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, 2019, international equities rose 21.51%, as measured by the MSCI ACWI ex USA Index (Net). In the first quarter of 2019, both United States (U.S.) and international markets recovered from a weak fourth quarter 2019 and surged due to productive trade negotiations between the U.S. and China, as well as by accommodative rhetoric and policy actions from the major central banks. The United Kingdom’s (U.K.’s) plan to leave the European Union (EU), also known as “Brexit,” remained a key area of concern with the British Parliament rejecting U.K. Prime Minister Theresa May’s deal for the third time. Oil prices benefited equity markets in a number of emerging markets countries, including Colombia and Russia. In the second quarter of 2019, trade tensions between China and the U.S. escalated in May but eased at the end of the quarter after the two countries agreed at the G20 summit to resume trade negotiations. Brexit was a major concern for the markets, with the U.K. avoiding an abruptno-deal departure after the EU leaders granted the U.K. a flexible extension until October 31, 2019. U.K. Prime Minister Theresa May announced that she would resign on June 7, 2019 after failing to secure a Brexit deal. In the third quarter of 2019, Boris Johnson was appointed as the new Prime Minister of the U.K. after his victory in the Conservative Party leadership contest. U.K. opposition parties vowed to block Prime Minister Johnson’s bid for a general election, and Parliament passed legislation requiring him to request an extension to the Brexit process if he failed to secure an acceptable deal. On the monetary front, the European Central Bank (ECB) unveiled a sweeping, long-term economic stimulus package to bolster the Eurozone economy against slowing growth and trade frictions, including an open-ended asset purchase program and more favorable bank lending conditions.

Emerging-markets equities lagged in the third quarter as Chinese equities were affected by trade tensions and slowing economic growth. Argentina’s stock market collapsed in August 2019 following President Mauricio Macri’s unexpected defeat byleft-wing opposition leader Alberto Fernandez in the national primary elections. In the fourth quarter of 2019, waning recession fears and forecasts for improving global

ahead of expectations thanks to strong momentum from the K12 segment. Shares of Cellnex, the largest independent European wireless tower operator, performed strongly after it announced the acquisition of a portfolio of towers in Italy, France, and Switzerland. Mergers & acquisitions (M&A) is a part of our investment thesis for Cellnex, and we expect the company to create value for shareholders over time by increasing tenancy ratios and driving asset efficiency from its growing asset base. The stock price for Ferrari performed well in the latter part of the twelve-month period as the Italy-based luxury sports car manufacturer posted strong first-quarter 2019 earnings which exceeded consensus expectations.

Top detractors from performance relative to the MSCI ACWI ex USA Index (Net) during the period included Unilever (Consumer Staples), Sony (Consumer Discretionary), and EnCana (Energy). Shares of Unilever fell during the latter half of the period as management announced sales were expected to miss their target for the 2019 fiscal year, citing a slowdown in the South Asia region which had been a growth driver for the company. Weakness in North America and West Africa also weighed on expectations. Sony’s stock price dropped after reporting lower-than-expected quarterly revenue led by losses within the company’s financial services division. We sold this position early in the period in favor of other opportunities. Encana is a Canadian based exploration and production (E&P) company. The company’s stock price fell over the period following the company’s mixed first-quarter 2019 earnings release, in which production came in below consensus.

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 continue to look for indications of a stronger rebound in an environment of weakening global economic data and increasing trade-related tensions. Major central banks have signaled their willingness to pursue further accommodative policy measures to support the expansion. While we believe the economic backdrop may be supportive for some parts of the equity market, there remain unresolved risks, like the U.S.-China trade dispute, which we continue to closely monitor. In our view, this issue is likely to remain unresolved in the near-term given the multitude of issues that need to be addressed. While China remains a large component of the Fund’s opportunity set, we remain mindful that economic and political uncertainty may continue to weigh on sentiment and cause further bouts of volatility. Currently, the majority of the Fund’s exposure in China continues to be in business models that are less tied to the economic cycle and have compelling valuation in our view. We believe the Brexit issue will have broader implications for economic progress in Europe as a whole. The Fund’s positioning is a result of ourbottom-up stock selection, and we will continue to monitor any future developments for potential opportunities and risks. While the environment is not supportive of an aggressive shift, we continue to look for opportunities in economically sensitive names that are attractively valued in our view. Across sectors, we continue to seek companies that are able to exploit technologies to bring significant positive change for the market they are addressing. This could be in terms of a company’s unique business model, differentiated process, or a new product. Overall, our investment approach leads us to seek companies with the potential to improve or sustain return on invested capital to a degree that the market underestimates. At the end of the period, the Fund’s largest

Average Annual Total Returns

for the Periods Ending 12/31/19

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 chart and table 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 recentmonth-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 December 31, 2019, 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.

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 0.69% and 0.94%, 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 December 31, 2019.

The Fund is closed to certain qualified pension and retirement plans. For more information, please see the Fund’s statutory prospectus.

Manager Discussion and Analysis

How did the Fund perform during the period?

The Class IA shares of Hartford MidCap HLS Fund returned 32.87% for the twelve-month period ended December 31, 2019, outperforming its benchmark, the S&P MidCap 400 Index, which returned 26.20% for the same period. For the same period, the Class IA shares of the Fund underperformed the 33.39% average return of the LipperMid-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, 2019. During the first quarter of 2019, U.S. equities rallied to their largest quarterly gain since 2009, buoyed by an accommodative shift in U.S. Federal Reserve (Fed) policy and guidance, optimism for a U.S.-China trade deal, relatively strong fourth-quarter 2018 earnings, and corporate buybacks. By the summer of 2019, unresolved U.S. trade frictions with China, Mexico, Japan, and the European Union (EU) unsettled markets and raised concerns about the potential risks to U.S. economic growth from increasing cost pressures, supply chain disruptions, and waning business confidence and investment plans. In the third quarter of 2019, U.S. equities rose as the U.S. economy remained resilient despite elevated geopolitical uncertainties and slowing global growth. U.S.-China trade relations were particularly volatile in the absence of meaningful compromises on key structural issues. Expectations for a protracted trade war and the potential for a longer-term decoupling of the world’s two largest economies eroded consumer and business confidence and curtailed capital spending. The Fed lowered its benchmark interest rate in July and September by a combined 0.50% in an effort to sustain the U.S. economic expansion and mitigate the risks of moderating growth and trade frictions. U.S. equity markets surged in the fourth quarter of 2019, as equities benefited from waning recession fears, improved trade sentiment, and accommodative Fed policies. In October, the Fed lowered interest rates for the final time in 2019, cutting rates by 0.25%. Trade tensions were volatile during the fourth quarter of 2019 but eased in December after the U.S. and China reached a phase one trade agreement. The U.S. House of Representatives voted to impeach President Trump; however, markets were unaffected as aRepublican-led Senate is unlikely to support his impeachment.

Returns during the period varied by market cap. Small- andmid-cap equities, as measured by the Russell 2000 Index and S&P MidCap 400 Index, respectively, underperformedlarge-cap equities, as measured by the S&P 500 Index. Ten of the eleven sectors within the S&P MidCap 400 Index posted positive returns during the period, led by the

revenue growth for the graduate program segment. We eliminated the Fund’s position on concerns for rising competitive intensity in that segment.

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 believe the Fed’s accommodative policy stance has enhanced confidence that the U.S. economy can continue to grow. However, volatility in equity markets will likely remain driven by geopolitical risks. We anticipate slower growth in 2020 than we saw in 2019.

Based on ourbottom-up, company-specific research and stock selection, as of the end of the period, the Fund was most overweight to the Information Technology, Healthcare, and Industrials sectors and most underweight to the Real Estate, Materials, and Financials sectors relative to the S&P MidCap 400 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.•Mid-cap securities can have greater risk and volatility thanlarge-cap securities.•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 December 31, 2019

Average Annual Total Returns

for the Periods Ending 12/31/19

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 chart and table 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 recentmonth-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 December 31, 2019, 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.

Performance information prior to June 4, 2012 represents performance of the Fund’s previoussub-adviser, Hartford Investment Management Company (“HIMCO”). As of June 4, 2012, HIMCO no longer served as thesub-adviser to the Fund.

Performance information prior to November 1, 2018, includes the Fund’s performance when it pursued different strategies. For more information, please see the Fund’s statutory prospectus.

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 MidCap Growth HLS Fund returned 39.79% for the twelve-month period ended December 31, 2019, outperforming its benchmark, the Russell Midcap Growth Index, which returned 35.47%. For the same period, the Class IA shares of the Fund also outperformed the 33.39% average return of the LipperMid-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, 2019. During the first quarter of 2019, U.S. equities rallied to their largest quarterly gain since 2009, buoyed by an accommodative shift in U.S. Federal Reserve (Fed) policy and guidance, optimism for a U.S.-China trade deal, relatively strong fourth-quarter 2018 earnings, and corporate buybacks. By the summer of 2019, unresolved U.S. trade frictions with China, Mexico, Japan, and the European Union (EU) unsettled markets and raised concerns about the potential risks to U.S. economic growth from increasing cost pressures, supply chain disruptions, and waning business confidence and investment plans. In the third quarter of 2019, U.S. equities rose as the U.S. economy remained resilient despite elevated geopolitical uncertainties and slowing global growth. U.S.-China trade relations were particularly volatile in the absence of meaningful compromises on key structural issues. Expectations for a protracted trade war between the U.S. and China and the potential for a longer-term decoupling of the world’s two largest economies eroded consumer and business confidence and curtailed capital spending. The Fed lowered its benchmark interest rate in July and September by a combined 0.50% in an effort to sustain the U.S. economic expansion and mitigate the risks of moderating growth and trade frictions. U.S. equity markets surged in the fourth quarter of 2019, as equities benefited from waning recession fears, improved trade sentiment, and accommodative Fed policies. In October, the Fed lowered interest rates for the final time in 2019, cutting rates by 0.25%. Trade tensions were volatile during the fourth quarter of 2019 but eased in December after the U.S. and China reached a phase one trade agreement. The U.S. House of Representatives voted to impeach President Trump; however, markets were unaffected as aRepublican-led Senate is unlikely to support his impeachment.

Returns varied by market cap during the period, aslarge-cap equities, as measured by the S&P 500 Index, outperformed both small- andmid-cap equities, as measured by the Russell 2000 Index and S&P MidCap 400 Index, respectively. All eleven sectors in the Russell Midcap Growth Index posted positive absolute returns during the period. The Information Technology (+44%), Real Estate (+39%), and Industrials (+38%) sectors rose the most, while the Energy (+8%) and Consumer Staples (+21%) sectors lagged the broader Russell Midcap Growth Index during the period.

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

For the first few months of 2019, the broad markets were generally strong. As we entered the summer, geopolitical concerns such as tariffs and an inverted yield curve stoked fears of possible recession if not slowing global growth. Later in the year, the mood shifted yet again with the market expressing more risk appetite. As we begin 2020, we continue to believe the U.S. economy is on solid footing and that accommodative policy from global central banks and improving trade relations between the U.S. and China may provide a solid backdrop.

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.•Mid-cap securities can have greater risk and volatility thanlarge-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.•The Fund’s focus on investments in particular sectors may increase its volatility and risk of loss if adverse developments occur.•Different investment styles may go in and out favor, which may cause the Fund to underperform the broader stock market.

Composition by Sector⁽¹⁾

as of December 31, 2019

Average Annual Total Returns

for the Periods Ending 12/31/19

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 chart and table 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 recentmonth-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 December 31, 2019, 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.

Effective 3/31/19, the Russell 2500 Value Index is no longer one of the Fund’s benchmarks. Hartford Funds Management Company, LLC, the investment manager, believes that the Russell MidCap Value Index better reflects the Fund’s investment strategy.

You cannot invest directly in an index.

See “Benchmark Glossary” for benchmark descriptions.

Performance information may reflect historical or current waivers/reimbursements without which performance would have been lower. For information on current expense waivers/reimbursements, please see the prospectus.

Manager Discussion and Analysis

How did the Fund perform during the period?

The Class IA shares of Hartford MidCap Value HLS Fund returned 31.20% for the twelve-month period ended December 31, 2019, outperforming the Fund’s benchmarks, the Russell Midcap Value Index, which returned 27.06%, and the Russell 2500 Value Index, which returned 23.56% for the same period. For the same period, the Class IA shares of the Fund also outperformed the 24.76% average return of the Lipper Mid-Cap Value Fund peer group, a group of funds with investment strategies similar to those of the Fund. Effective March 31, 2019, the Russell 2500 Value Index is no longer one of the Fund’s benchmarks.

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, 2019. During the first quarter of 2019, U.S. equities rallied to their largest quarterly gain since 2009, buoyed by an accommodative shift in U.S. Federal Reserve (Fed) policy and guidance, optimism for a U.S.-China trade deal, relatively strong fourth-quarter 2018 earnings, and corporate buybacks. By the summer of 2019, unresolved U.S. trade frictions with China, Mexico, Japan, and the European Union (EU) unsettled markets and raised concerns about the potential risks to U.S. economic growth from increasing cost pressures, supply chain disruptions, and waning business confidence and investment plans. In the third quarter of 2019, U.S. equities rose with the U.S. economy remaining resilient despite elevated geopolitical uncertainties and slowing global growth. U.S.-China trade relations were particularly volatile in the absence of meaningful compromises on key structural issues. Expectations for a protracted trade war between the U.S. and China and the potential for a longer-term decoupling of the world’s two largest economies eroded consumer and business confidence and curtailed capital spending. The Fed lowered its benchmark interest rate in July and September by a combined 0.50% in an effort to sustain the U.S. economic expansion and mitigate the risks of moderating growth and trade frictions. U.S. equity markets surged in the fourth quarter of 2019, as equities benefited from waning recession fears, improved trade sentiment, and accommodative Fed policies. In October, the Fed lowered interest rates for the final time in 2019, cutting rates by 0.25%. Trade tensions were volatile during the fourth quarter of 2019 but eased in December after the U.S. and China reached a phase one trade agreement. The U.S. House of Representatives voted to impeach President Trump; however, markets were unaffected as a Republican-led Senate is unlikely to support his impeachment.

The Fund’s outperformance relative to the Russell Midcap Value Index was largely driven by security selection. Positive stock selection within the Information Technology, Industrials and Materials sectors more than offset negative stock selection within the Financials, Consumer Discretionary, and Utilities sectors. Sector allocation, a result of the bottom-up security selection process, also contributed positively to relative results over the period, primarily due to the Fund’s overweight to

belief that a key part of the economy is on positive footing. The housing market gained momentum, fueled by strong job and income growth and historically low interest rates. Housing permits surged to a twelve-year high, new home sales realized their best three-month performance since 2007, and homebuilder sentiment was at its highest level since 1999. Manufacturing remained in contractionary territory for the fourth consecutive month in November 2019, as trade policy uncertainty continued to weigh on business investment. The services sector slowed but remained in expansionary territory. Although consumer confidence remained elevated, it eased later in the year as expectations and optimism moderated amid a volatile global environment.

While we expect continued volatility in the near term, we continue to seek cyclical opportunities where stock prices appear attractively valued in multiple economic scenarios.

The Fund ended the year with the largest over weights to the Information Technology, Materials, and Financials sectors relative to the Russell Midcap Value Index, and the largest underweights to the Utilities, Real Estate and Consumer Discretionary sectors, relative to the Russell Midcap Value 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.•Mid-cap securities can have greater risk and volatility thanlarge-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.•The Fund’s focus on investments in particular sectors may increase its volatility and risk of loss if adverse developments occur.•Different investment styles may go in and out favor, which may cause the Fund to underperform the broader stock market.

Composition by Sector⁽¹⁾

as of December 31, 2019

Average Annual Total Returns

for the Periods Ending 12/31/19

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 chart and table 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 recentmonth-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 December 31, 2019, 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.

You cannot invest directly in an index.

See “Benchmark Glossary” for benchmark descriptions.

Performance information prior to July 21, 2010 represents performance of the Fund’s previous additionalsub-adviser, Hartford Investment Management Company (“HIMCO”). As of July 21, 2010, HIMCO no longer serves as an additionalsub-adviser to the Fund.

As shown in the Fund’s current prospectus, the total annual fund operating expense ratios for Class IA and Class IB were 0.65% and 0.90%, 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 December 31, 2019.

Manager Discussion and Analysis

How did the Fund perform during the period?

The Class IA shares of Hartford Small Cap Growth HLS Fund returned 35.81% for the twelve-month period ended December 31, 2019, outperforming its benchmark, the Russell 2000 Growth Index, which returned 28.48%. For the same period, the Class IA shares of the Fund also outperformed the 28.15% 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, 2019. During the first quarter of 2019, U.S. equities rallied to their largest quarterly gain since 2009, buoyed by an accommodative shift in U.S. Federal Reserve (Fed) policy and guidance, optimism for a U.S.-China trade deal, relatively strong fourth-quarter 2018 earnings, and corporate buybacks. By the summer of 2019, unresolved U.S. trade frictions with China, Mexico, Japan, and the European Union (EU) unsettled markets and raised concerns about the potential risks to U.S. economic growth from increasing cost pressures, supply chain disruptions, and waning business confidence and investment plans. In the third quarter of 2019, U.S. equities rose for the third consecutive quarter, with the U.S. economy remaining resilient despite elevated geopolitical uncertainties and slowing global growth. U.S.-China trade relations were particularly volatile in the absence of meaningful compromises on key structural issues. Expectations for a protracted trade war between the U.S. and China and the potential for a longer-term decoupling of the world’s two largest economies eroded consumer and business confidence and curtailed capital spending. The Fed lowered its benchmark interest rate in July and September by a combined 0.50% in an effort to sustain the U.S. economic expansion and mitigate the risks of moderating growth and trade frictions. U.S. equity markets surged in the fourth quarter of 2019, as equities benefited from waning recession fears, improved trade sentiment, and accommodative Fed policies. In October, the Fed lowered interest rates for the final time in 2019, cutting rates by 0.25%. Trade tensions were volatile during the fourth quarter of 2019 but eased in December after the U.S. and China reached a phase one trade agreement. The U.S. House of Representatives voted to impeach President Trump; however, markets were unaffected given that the Republican-led Senate is unlikely to support his impeachment.

in the stock during the period. Shares of Arrowhead Pharmaceuticals, a U.S.-based pharmaceuticals company, rose during the period. The company recently announced strong fiscal year 2019 operating results and plans to offer 4 million common shares in a public offering. We continued to not hold Arrowhead Pharmaceuticals in the Fund as of the end of the period. 2U is a U.S.-based online educational services company. The company’s stock declined during the period after it sharply widened its full-year adjusted loss expectation. We eliminated the Fund’s position in the stock. Merit Medical Systems (Healthcare) was the top absolute detractor 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?

As we look into 2020, many of the constructive fundamental drivers of U.S. economic growth in 2019 persist. We believe that labor markets remain healthy, as wage gains continue to bolster consumer confidence but are not expected to trigger outsized inflation due to continued productivity improvements. In our view, the U.S. housing market has turned the corner after six quarters of negative growth, responding to interest rate cuts by the Fed. Moving forward, we believe that Fed action is likely to be more gradual, having now achieved targeted levels of inflation. This may also result in less volatility for the U.S. dollar (U.S. Dollar).

We believe that trade negotiations between the U.S. and China will remain vitally important to markets. In our view, the year ended with encouraging progress, as the “List 4” tariffs slated for December 2019 implementation were delayed, and indications that forward progress for a phase one agreement were in place. Additionally, the U.S. House of Representatives passed the tri-party United States-Mexico-Canada Agreement (USMCA), a replacement for the North American Free Trade Agreement (NAFTA) which is expected to be ratified by the U.S. Senate. The ratification of this trade agreement is expected to provide important certainty to North American supply chains.

As we begin 2020, we believe U.S. politics will first be dominated by a historic presidential impeachment trial in the U.S. Senate, before yielding to a rapid succession of Democratic primaries which will provide more certainty into both the eventual Democratic candidate as well as the main platform issues to be put forward by that party in the presidential election. The outcome at the ballot box could warrant future action in the Fund, but given the wide range of possible outcomes at this point, we believe this bears more monitoring than action at this time.

At the end of the period, the Fund’s largest overweights were to the Financials, Consumer Discretionary, and Consumer Staples sectors, while the Fund’s largest underweights were to the Real Estate, Utilities, and Communication Services 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 risk and volatility thanlarge-cap securities.•The Fund’s focus on investments in particular sectors may increase its

Average Annual Total Returns

for the Periods Ending 12/31/19

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 chart and table 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 recentmonth-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 December 31, 2019, 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.

You cannot invest directly in an index.

See “Benchmark Glossary” for benchmark descriptions.

Performance information prior to July 21, 2010 represents performance of the Fund’s previous additionalsub-adviser, Hartford Investment Management Company (“HIMCO”). As of July 21, 2010, HIMCO no longer serves as an additionalsub-adviser to the Fund.

As shown in the Fund’s current prospectus, the total annual fund operating expense ratios for Class IA and Class IB were 0.78% and 1.03%, 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 December 31, 2019.

Manager Discussion and Analysis

How did the Fund perform during the period?

The Class IA shares of Hartford Small Company HLS Fund returned 37.00% for the twelve-month period ended December 31, 2019, outperforming its benchmark, the Russell 2000 Growth Index which returned 28.48% for the same period. For the same period, the Class IA shares of the Fund also outperformed the 28.15% average return of the LipperSmall-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, 2019. During the first quarter of 2019, U.S. equities rallied to their largest quarterly gain since 2009, buoyed by an accommodative shift in U.S. Federal Reserve (Fed) policy and guidance, optimism for a U.S.-China trade deal, relatively strong fourth-quarter 2018 earnings, and corporate buybacks. By the summer of 2019, unresolved U.S. trade frictions with China, Mexico, Japan, and the European Union (EU) unsettled markets and raised concerns about the potential risks to U.S. economic growth from increasing cost pressures, supply chain disruptions, and waning business confidence and investment plans. In the third quarter of 2019, U.S. equities rose as the U.S. economy remained resilient despite elevated geopolitical uncertainties and slowing global growth. U.S.-China trade relations were particularly volatile in the absence of meaningful compromises on key structural issues. Therefore, there were reasons to expect a protracted trade war and for a longer-term decoupling of the world’s two largest economies, which eroded consumer and business confidence as well as curtailed capital spending. The Fed lowered its benchmark interest rate in July and September by a combined 0.50% in an effort to sustain the U.S. economic expansion and mitigate the risks of moderating growth and trade frictions. U.S. equity markets surged in the fourth quarter of 2019, as equities benefited from waning recession fears, improved trade sentiment, and accommodative Fed policies. In October, the Fed lowered interest rates for the final time in 2019, cutting rates by 0.25%. Trade tensions were volatile during the fourth quarter of 2019 but eased in December after the U.S. and China reached a phase one trade agreement. The U.S. House of Representatives voted to impeach President Trump; however, markets were unaffected as aRepublican-led Senate is unlikely to support his impeachment.

Returns varied by market cap during the period, aslarge-cap equities, as measured by the S&P 500 Index, outperformed both small- andmid-cap equities, as measured by the Russell 2000 Index and S&P MidCap 400 Index, respectively. Ten of the eleven sectors in the Russell 2000 Growth Index had positive returns during the period. The Information

of cloud-based software for online education courses, traded down after management meaningfully lowered full year guidance and turned their focus away fromtop-line growth towards profitability. The company cited increasing competition in its graduate degree segment as a headwind totop-line growth. Green Dot (Financials) was a top absolute detractor from 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?

As measured by the Russell 2000 Growth Index, the U.S. small cap growth asset class started strong in 2019 (+17.2% in 1Q19) and ended the year much the same way (+11.4%). In between those two strong periods of performance, the asset class weakened on the back of a combination of recessionary fears and geopolitical/tariff-related concerns. Additionally, investors expressed concerns over elevated valuations particularly in the software industry, and as a result,price-to-earnings ratios generally contracted. We used this heightened volatility as an opportunity to trim and eliminate some of the Fund’s exposures as we entered the summer. Our fair value targets were met, and we observed a more attractive upside/downside profile inre-emerging growers. As a result, we introduced more balance into the Fund and added exposure to holdings in sectors such as Industrials, Consumer Discretionary, and Financials, while reducing exposure to the Information Technology and Healthcare sectors. As we approach the new year, we anticipate a more challenging, late cycle macro environment.

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 Industrials, Real Estate, and Utilities 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 risk and volatility thanlarge-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.•The Fund’s focus on investments in particular sectors may increase its volatility and risk of loss if adverse developments occur.•Different investment styles may go in and out favor, which may cause the Fund to underperform the broader stock market.

Average Annual Total Returns

for the Periods Ending 12/31/19

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 chart and table 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 recentmonth-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 December 31, 2019, 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.

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 December 31, 2019.

The Fund is closed to certain qualified pension and retirement plans. For more information, please see the Fund’s statutory prospectus.

Manager Discussion and Analysis

How did the Fund perform during the period?

The Class IA shares of Hartford Stock HLS Fund returned 31.22% for the twelve-month period ended December 31, 2019, underperforming the Fund’s benchmark, the Russell 1000 Index, which returned 31.43% for the same period. For the same period, the Class IA shares of the Fund also underperformed the 29.61% average return of the LipperLarge-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 ending December 31, 2019. During the first quarter of 2019, U.S. equities rallied to their largest quarterly gain since 2009, buoyed by an accommodative shift in U.S. Federal Reserve (Fed) policy and guidance, optimism for a U.S.-China trade deal, relatively strong fourth-quarter 2018 earnings, and corporate buybacks. By the summer of 2019, unresolved U.S. trade frictions with China, Mexico, Japan, and the European Union (EU) unsettled markets and raised concerns about the potential risks to U.S. economic growth from increasing cost pressures, supply chain disruptions, and waning business confidence and investment plans. In the third quarter of 2019, U.S. equities rose for the third consecutive quarter, with the U.S. economy remaining resilient despite elevated geopolitical uncertainties and slowing global growth. U.S.-China trade relations were particularly volatile in the absence of meaningful compromises on key structural issues. Expectations for a protracted trade war and the potential for a longer-term decoupling of the world’s two largest economies eroded consumer and business confidence and curtailed capital spending. The Fed lowered its benchmark interest rate in July and September by a combined 0.50% in an effort to sustain the U.S. economic expansion and mitigate the risks of moderating growth and trade frictions. U.S. equity markets surged in the fourth quarter of 2019, as equities benefited from waning recession fears, improved trade sentiment, and accommodative Fed policies. In October, the Fed lowered interest rates for the final time in 2019, cutting rates by 0.25%. Trade tensions were volatile during the fourth quarter of 2019 but eased in December after the U.S. and China reached a phase one trade agreement. The U.S. House of Representatives voted to impeach President Trump; however, markets were unaffected as aRepublican-led Senate is unlikely to support his impeachment.

Returns varied by market cap during the period, aslarge-cap equities, as measured by the S&P 500 Index, outperformed both small- andmid-cap equities, as measured by the Russell 2000 Index and S&P MidCap 400 Index, respectively. During the twelve-month period, all eleven sectors within the Russell 1000 Index rose, led by the Information Technology (+50%) and Communication Services (+33%) sectors. Alternatively, the Energy (+11%), Healthcare (+21%), and Materials (+24%) sectors lagged on a relative basis.

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 we look at 2020, we see a likely continuation of good economic conditions in the U.S. The labor market appears healthy and consumer confidence is strong, in our view. And while we expect to see further accommodative policy from global central banks, we view this loose monetary posture as a potential source of dislocation, as the inevitable shift to higher rates is expected to have a dampening effect on asset prices.

We see uncertainties on the horizon, including U.S. elections and impeachment proceedings, evolving U.S.-China trade relations, and other global geopolitical risks. As a result, we anticipate volatility around near-term events and remain mindful of the longer-term risks. In the near term, however, we continue to have a positive backdrop against which to invest.

At the end of the period, the Fund’sbottom-up investment approach resulted in overweight exposures to the Industrials, Consumer Staples, and Healthcare sectors, relative to the Russell 1000 Index. The Fund’s largest underweights at the end of the period relative to the Russell 1000 Index were to the Information Technology, Communication Services, and Utilities sectors.

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.•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.

Composition by Sector⁽¹⁾

as of December 31, 2019

Average Annual Total Returns

for the Periods Ending 12/31/19

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 chart and table 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 recentmonth-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 December 31, 2019, 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.

Performance information prior to March 5, 2012 represents performance of the Fund’s previoussub-adviser, Hartford Investment Management Company (“HIMCO”). As of March 5, 2012, HIMCO no longer served as thesub-adviser to the Fund.

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 December 31, 2019.

Manager Discussion and Analysis

How did the Fund perform during the period?

The Class IA shares of Hartford Total Return Bond HLS Fund returned 10.65% for the twelve-month period ended December 31, 2019, outperforming its benchmark, the Bloomberg Barclays U.S. Aggregate Bond Index, which returned 8.72% for the same period. For the same period, the Class IA shares of the Fund also outperformed the 8.79% 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?

Over the period, global fixed-income markets generated largely positive total returns, driven by a decline in sovereign debt yields across most markets – particularly in the first three quarters of 2019. By the end of the period, yields increased across most markets amid stabilizing global activity indicators and progress on trade talks, despite continued accommodative global central bank policies. Geopolitical uncertainty remained elevated amid ongoing trade talks between the United States (U.S.) and China, negotiations surrounding the United Kingdom’s (U.K.’s) exit from the European Union EU, also known as “Brexit”, and U.S. presidential impeachment proceedings. Despite these concerns, corporate bond spreads tightened due to optimism that monetary accommodation could offset the drag on global growth from restrictive trade policies. The U.S. dollar cemented its safe-haven status, strengthening versus most currencies amid trade frictions and slowing global growth prospects. Inflation showed no meaningful acceleration even as wage growth edged higher.

Global monetary policies continued along a more accommodative path, in aggregate. The U.S. Federal Reserve (Fed) cut interest rates three times before deciding to take a more patient approach on future adjustments. Meanwhile, the European Central Bank (ECB) launched a package of stimulus measures, including an interest rate cut, resumption of asset purchases that the central bank plans to continue “as long as necessary,” and the introduction of tiered deposit rates to exempt banks from negative interest rates. The Bank of Japan (BoJ) maintained its short-term negative interest rate policy, while pledging to guide10-year government bonds to around 0.0%. The Norges Bank, an outlier among major central banks this year, increased interest rates three times but trimmed the projected path for interest rate increases, citing global uncertainties.

The Fund implemented tactical duration and yield curve positions during the period, which detracted from performance relative to the Bloomberg Barclays U.S. Aggregate Bond Index. The Fund maintained exposure to Treasury Inflation-Protected Securities (TIPS), which had a slightly positive impact on relative performance during the period as TIPS outperformed duration-equivalent nominal U.S. Treasuries in the fourth quarter of 2019.

During the period, the Fund used Treasury futures, swaps, and options to manage duration and yield curve positioning. The Fund also used currency forwards, futures, and options to implementnon-U.S. rate and currency positions. Credit default swaps (CDS) were used to manage credit exposure and Investment Grade and High Yield CDS index positions were used to seek liquidity and to manage overall portfolio risk. The use of derivatives in general slightly contributed to overall performance. In particular, the High Yield hedges were additive to performance relative to the Bloomberg Barclays U.S. Aggregate Bond Index during the period, and the Investment Grade CDS positions also had a small positive impact on relative performance.

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 moderatelypro-cyclical risk posture, consistent with our expectation for continued positive U.S. economic fundamentals. Inflation expectations remain stubbornly below central banks’ targets, but a material upside inflation surprise remains a risk to our outlook. Inflation breakeven positioning is near neutral, but we would consider adding to the position if the interest rate environment stabilizes.

We ended the period with an underweight positioning in the Fund to investment-grade credit in favor of holding anout-of-benchmark allocation to high yield and bank loans. The Fund held an overweight to agency MBS and maintained anout-of-benchmark exposure to selectnon-agency RMBS. The Fund also held CMBS and CLOs based on what we consider to be attractive valuations. The Fund also continued to hold select exposure to emerging markets (EM) corporate debt where valuations were attractive, in our view.

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, and interest-rate risk. As interest rates rise, bond prices generally fall.•Investments in high-yield (“junk”) bonds involve greater risk 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.•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 theTo-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