CALVERT UNCONSTRAINED BOND FUND A More Expansive Approach to Fixed-Income Investing

CALVERT UNCONSTRAINED BOND FUND A More Expansive Approach to Fixed-Income Investing

A Challenging Environment for Investors MOVING BEYOND TRADITIONAL FIXED-INCOME INVESTING ALONE For many advisors and their clients, fixed-income plays a core role in an asset allocation strategy, providing potential income, return and diversification benefits. It has been an extremely tumultuous time since the end of the recession in June 2009. Interest rates and yields are hovering near historic lows, as the Federal Reserve (the Fed) continues trying to maintain the recovery and stimulate the economy by encouraging lending. After several years of quantitative easing, the Fed ended its program in a measured fashion in October 2014, raising the potential for rising interest rates. This prospect is a looming concern for many income-focused investors, who fear a corresponding fall in bond prices. It can be challenging for investors to find a fixed-income strategy that will provide attractive performance under a full market cycle, which encompasses both bull market and bear market periods. UNCERTAIN INVESTMENT CLIMATE AHEAD The Fed has stated its intention to maintain the current low policy rate environment for some time, and to raise rates in a thoughtful manner when it does decide to do so. As rates rise, impacting the prices of existing bonds, many investors are struggling to determine an appropriate strategy that will accommodate today s relatively low interest-rate environment as well as future interest-rate movements. Fixed-income investors may consider investing in longer-term or lower-quality fixed-income securities, that may provide the potential to generate higher income and returns. But with the opportunity for higher returns also comes the potential for higher risk and volatility, and investors may wonder which fixed-income asset category represents the best potential. ALL BEAR MARKET INTEREST-RATE CYCLES ARE NOT EQUAL In a bear market interest-rate cycle, fixed-income categories may react differently depending on a range of factors in the global and domestic economies and markets. Typically, however, securities with higher yields and exposure to a broad range of factors (sector, global, etc.) have historically experienced higher returns in bull market scenarios and lower losses in bear market environments. The current market environment is partially a reflection of the end of the Fed s quantitative easing program, not a natural long-term interest-rate-driven bear market cycle. Although there are thematic similarities in the causes and results of these periods, there are also differences which may impact market reaction. This underscores the uncertainty which exists and highlights the value of professional management of a diversified portfolio that follows a disciplined process and focuses on risk management. Managers can focus on identifying and analyzing the underlying factors that may impact which fixed-income categories have potential to generate stronger Yield is typically greater than duration*, but quantitative easing has created the opposite situation, highlighting the potential benefits of active management in this environment. BARCLAYS AGGREGATE INDEX YIELD VS. DURATION 12 10 Yield to Worst (%) Option Adjusted Duration (Years) 8 6 4 2 0 Jan-89 Jan-92 Jan-95 Jan-98 Jan-01 Jan-04 Jan-07 Jan-10 Jan-13 Source: Barclays *Duration measures a portfolio s sensitivity to changes in interest rates. Generally, the longer the duration, the greater the change in value in response to a given change in interest rates.

ANNUAL TOTAL RETURNS FROM HIGHEST TO LOWEST: 2004-2013 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 10.87% 5.06% 11.74% 9.48% 8.52% 57.51% 15.19% 17.13% 15.59% 7.42% 9.38% 3.76% 6.74% 6.96% 4.79% 51.62% 10.69% 8.35% 12.73% 5.29% 9.27% 2.72% 6.64% 6.09% 4.67% 16.80% 10.13% 5.75% 9.66% 1.24% 5.24% 2.66% 5.22% 5.87% 2.41% 16.04% 8.47% 5.64% 9.37% 0.25% 5.17% 2.61% 4.69% 5.11% -1.13% 13.52% 5.54% 4.38% 6.75% 0.01% 4.70% 2.52% 4.51% 4.77% -3.08% 6.93% 5.50% 3.04% 5.51% -1.41% 2.44% 1.96% 4.38% 3.60% -3.92% 5.75% 5.44% 1.52% 4.32% -2.01% 0.94% 1.35% 4.26% 2.24% -26.39% 0.76% 0.67% 0.51% 0.23% -2.60% 0.78% -4.49% 3.47% 2.08% -29.10% 0.24% 0.03% 0.02% 0.01% -6.62% Indices are unmanaged and reflect no deductions for sales charges or management expenses. It is not possible to invest directly in an index. This chart is for illustrative purposes only and is not indicative of any actual investment, including investment in Calvert funds. The performance data quoted represents past performance, which does not guarantee future results. Source: Morningstar. Each sector is represented by an index as follows: by the Barclays Global Aggregate Index; by the BofA Merrill Lynch High Yield Master II Index; by the Barclays U.S. Credit Index; by the Barclays U.S. Credit Index; by the Lipper Index; by the Barclays Fixed Mortgage Security Index; Short- Term by the Barclays U.S. Credit 1 5 Year Index; by the Barclays Short Treasury 9 12 Month Index, and by the S&P/LSTA Leveraged Loan Index. performance under various market environments, and invest in those categories that appear most attractive. A pool of diversified fixed-income securities may help to enhance returns while managing overall volatility. EXPLORING UNCONSTRAINED BOND FUND ALLOCATION OPPORTUNITIES In this uncertain fixed-income environment, investors may wish to look beyond traditional, core bond funds and consider a bond fund that has the ability to look across broad markets and fixed-income categories. This allows investors to obtain active, professional management of allocations to fixed-income categories, as well as the selection of the underlying securities. At Calvert, we believe that a fund that can invest to generate positive total returns over a complete market cycle, with flexibility regarding sector, duration, geography and credit, may provide an opportunity to benefit from fixed-income investing in any interest-rate environment. Based on an investor s risk profile, time horizon, investment goals and circumstances, an allocation to an unconstrained bond fund can be a complement and diversifier to a core fixed-income portion of a portfolio.

The Flexibility of Unconstrained Bond A MORE EXPANSIVE APPROACH Traditional bond funds typically have a relatively specific focus and measure performance versus a defined benchmark. Conversely, an unconstrained bond fund gives fund managers the ability to pursue fixed-income opportunities across the yield curve, the various bond market sectors, geographic regions and foreign currencies. Unlike more traditional strategies, an unconstrained bond fund s investment and return parameters are not constrained by a traditional benchmark. This allows the fund manager to focus on investing in the best fixed-income ideas, wherever and whenever they may occur, regardless of market cycle or financial and economic situation. This flexibility can be of particular benefit to investors, as the relative returns of different types of bonds can change significantly from cycle to cycle. INVESTMENT FLEXIBILITY AND ENHANCED ACCESS An unconstrained bond fund has the potential to benefit from access to a broader investment universe across the duration, sector, credit and geographic spectrum, increasing diversification and the potential for downside protection during a rising interestrate cycle. Many unconstrained bond funds have the flexibility to adapt their allocations to different investments in order to provide potential positive returns across different market environments, including rising-rate environments, by utilizing the following tactical strategies: Duration management across a large range to address bull and bear interest-rate markets Cash, sector and other allocation adjustments depending on the market environment Depending on the fund, it may have the flexibility to utilize riskmanagement tools, such as derivatives and hedging techniques to potentially reduce volatility and provide downside protection BROAD DIVERSIFICATION Because it is not bound by a traditional benchmark, an unconstrained bond fund can help investors achieve greater diversification in fixed-income investing within a single fund. Depending on the fund parameters, it may: Offer flexibility to invest in a broad array of sectors and securities Seek to take advantage of global trends and opportunities Participate in foreign currency bond markets when appropriate Manage interest-rate duration based on interest-rate expectations Position for shifts in the yield curve Position for a rise or fall in interest rates, equity and currency market volatilities Invest up and down the credit-quality spectrum when riskadjusted spreads warrant Possess the ability to use derivatives to help manage risk A COMPLEMENT TO CORE FIXED INCOME An unconstrained bond fund may also serve as a complement to core fixed-income investments, which are most heavily-weighted in high-quality, government-guaranteed and corporate bonds (typically benchmarked to the Barclays Aggregate Index). Unconstrained bond funds may also provide diversification benefits, because they exhibit a low correlation to core fixed-income investments. Investors and advisors should keep in mind that not all unconstrained bond funds are alike. Depending on stated objectives, funds may focus on one or more aspects of adding value, such as generating a greater income stream, capital appreciation, or dampening sensitivity to changes in interest rates. Given the number of different variables to consider, careful selection of an experienced manager with expertise across a range of fixed-income categories can have a significant impact on investment results. The size of an allocation made to an unconstrained bond fund will depend on an investor s and advisor s view of the future direction of rates and inflation, as well as the overall economic, financial and market environments. For example, if it appears that rates are going to rise rapidly as higher inflation becomes likely, investors seeking to preserve their capital may consider increasing their allocation to an unconstrained bond fund that actively manages duration and may invest in fixed-income securities that are less sensitive to interestrate risk.

Unconstrained bond funds are managed to perform well in different market environments, not just under bear market scenarios. Unconstrained bond fund managers may also shift portfolio strategy in anticipation of changes in the interest-rate cycle and thus can be positioned to benefit from the capital gains component of total returns which are inherent in a bond bull market. ADAPTABLE ALL-WEATHER APPROACH: PROVIDING DOWNSIDE PROTECTION Unconstrained bond funds can potentially provide protection against different types of investment and market risk, including currency exposure, inflation, interest-rate risk and long-term declines in the U.S. dollar. Tactics that help provide downside protection can be an important component of unconstrained bond funds. In addition to diversification, unconstrained bond funds can also use liquidity to help reduce volatility, strategically increasing cash and short-term holdings when market uncertainty warrants it. Fund managers may also choose to invest in the securities of a particular country in anticipation of exchange-rate fluctuation. Derivative market products offer a rich array of tools to allow the fund manager to manage risk and provide potential downside protection....while BENEFITING FROM UPSIDE PARTICIPATION Unconstrained bond funds are also able to take advantage of the upside available in a bond bull market environment by shifting their investments as the cycle changes. In addition, fund managers have the flexibility to move into sectors or securities where wide yield spreads make those securities attractive. For example, if credit spreads are wide, a fund manager may choose to buy corporate bonds versus government bonds to obtain additional yield, although corporate bonds also represent a riskier security. Derivative market products provide tactics to allow the fund manager to structure the portfolio for upside participation. An allocation to an absolute return strategy, such as an unconstrained bond fund, will depend on an investor s goals, risk profile and time horizon, the interest-rate outlook and inflationary views: NARROW RATE RANGE STEADY RATE MOVEMENT RAPID RATE MOVEMENT INCOME OBJECTIVE INCOME OBJECTIVE INCOME OBJECTIVE Unconstrained Bond Strategy Unconstrained Bond Strategy Unconstrained Bond Strategy Core Specialty Strategies Core Specialty Strategies Core Specialty Strategies CAPITAL PRESERVATION OBJECTIVE CAPITAL PRESERVATION OBJECTIVE CAPITAL PRESERVATION OBJECTIVE Unconstrained Bond Strategy Unconstrained Bond Strategy Unconstrained Bond Strategy Core Specialty Strategies Core Specialty Strategies Core Specialty Strategies

Integrating the Best Ideas THE CALVERT UNCONSTRAINED BOND FUND ADVANTAGE The Calvert Unconstrained Bond Fund is a strong complement to our array of fixed-income offerings. With enhanced access to a diversified global fixed-income universe of asset categories, the Fund s management team has the flexibility to adjust the portfolio for the best relative value available in the bond market at the sector and individual security levels. While many other unconstrained bond funds have a lower limit of zero years of portfolio duration, thus inhibiting their ability to take advantage of a rising-rate cycle, Calvert Unconstrained Bond Fund s duration minimum is minus three years. The Fund s duration maximum of positive eight years allows the manager to meaningfully participate in a falling-rate cycle. ACCESS TO OPPORTUNITIES GLOBALLY The Fund management team focuses on uncovering the best ideas globally, using a relative-value assessment to select and determine optimal exposure. Our investment management approach combines a top-down macro view with deep bottom-up fundamental analysis, including environmental, social and governance (ESG) research, to help us identify securities with the best absolute return potential. Calvert s portfolio team has the strong quantitative and risk-management talent required to evaluate more complex and innovative opportunities in securitized markets, looking at their potential to offer attractive risk-adjusted returns. COLLABORATIVE APPROACH Calvert s investment management is highly collaborative and benefits from the free flow of information between the fixed income, equity and sustainability teams. The Calvert Investments Fixed-Income Strategy Committee, which is deeply involved in the investment management process of all fixed-income funds, is comprised of senior fixed-income individuals, including the CIO of Fixed Income, senior strategists, portfolio managers and senior credit professionals. The Calvert Unconstrained Bond Fund portfolio management team is made up of the CIO, two senior portfolio managers, Calvert s senior fixed-income risk analyst and a fixedincome strategist. The Fund team meets frequently to discuss performance attribution, market outlook and portfolio positioning. CALVERT UNCONSTRAINED BOND FUND PROFILE CUBAX (A SHARES) 13161X105 (A SHARES) INVESTMENT OBJECTIVE INVESTMENT APPROACH ESG INTEGRATION GEOGRAPHIC LIMITS CREDIT RANGES DERIVATIVES DURATION Seeks positive absolute returns over a full market cycle, regardless of market conditions, without the constraint of a benchmark The Fund follows a flexible investment process that allocates investments across global fixed-income markets and uses various investment strategies. The Fund uses an active trading strategy, seeking relative value to earn incremental income Calvert s integrated investment approach complements traditional fundamental security analysis with Calvert s assessment of critical ESG issues May invest in foreign securities, and up to 50% of net assets may be in securities and instruments related to emerging market countries May invest without limitation in below-investment-grade, high-yield debt May invest in derivatives and non-rated securities to enhance Fund returns, increase liquidity and/or gain exposure to certain instruments in a more efficient way Negative three years to positive eight years, depending on the portfolio managers outlook on changing market, economic and political conditions

CALVERT S FIXED-INCOME PROCESS Duration/ Yield Curve Sector Selection Security Selection Portfolio Construction/ Risk Controls Portfolio Monitoring Set duration targets Identify value across broad sectors Identify fundamental and relative value, analyzing a wide range of factors, including ESG Select undervalued securities within sectors, integrating ESG lens when assessing fundamentals Build portfolio by seeking to optimize risk/return characteristics given risk management constraints Risk and diversification monitoring 1 2 3 4 5 EXTENSIVE EXPERIENCE IN FIXED-INCOME INVESTMENT MANAGEMENT Unconstrained bond funds require a high level of active management, knowledge and experience across a broad range of markets in order to quickly synthesize and respond to a continuous flow of information. With strong access to issuers, Calvert possesses a proven ability to uncover attractive investment opportunities in volatile markets. Calvert has deep experience in managing a broad array of fixed-income categories across the duration and credit spectrum. In addition to the Calvert Unconstrained Bond Fund, our bond fund offerings include ultra-short income, short duration, long-term income, high-yield, government, and other objectives, with strong long-term performance. Within our fixed-income team, our portfolio managers, strategists, credit and risk analysts and trading specialists possess significant experience in analyzing securitized and high-yield markets, derivatives, duration and yield curve shape, and investment-grade corporate bonds. NIMBLE, ACTIVE INVESTMENT AND RISK MANAGEMENT We are active managers, utilizing fundamental and relative value analysis to select securities and seek to optimize the risk/return characteristics of a portfolio through modeling and riskmanagement controls, with a senior fixed-income risk analyst as an integral member of every Calvert Fund management team. The Fixed-Income Investment Strategy Committee is active in providing input for all of our fixed-income funds to ensure exchange and communication of information as well as consistent oversight and risk management. The Committee is responsible for developing the fixed-income team s broad economic view and outlook on interest rates, which guides decisions on duration, yield curve and sector positioning. CALVERT S UNIQUE ESG PERSPECTIVE The Calvert Unconstrained Bond Fund benefits from our in-depth, proprietary environmental, social and governance research, making it the only unconstrained bond fund to fully integrate ESG factors as part of its investment analysis. Our disciplined approach to ESG analysis is integrated into the overall fixed-income process and is especially valuable in assessing the creditworthiness of potential investments. We believe analyzing ESG criteria can create an information advantage by identifying factors traditional investment analysis may not uncover or value correctly. This allows us to: Identify opportunities in innovation and adaptation that other investment managers may not realize Expose potential risk that may not be uncovered by others in less transparent markets Leverage opportunities to benefit from market inefficiencies

LEARN MORE ABOUT THE CALVERT UNCONSTRAINED BOND FUND Your clients may benefit from using the Calvert Unconstrained Bond Fund as a complement to a core fixed-income portfolio. By focusing on achieving positive absolute returns over a full market cycle, the Fund is structured to take advantage of investment opportunities at any time while protecting against downside risk. It has the flexibility to seek out the best ideas globally without the constraint of managing to a benchmark. To learn about how the Calvert Unconstrained Bond Fund can help investors achieve their goals, contact Calvert Investments at 800.368.2750 or visit calvert.com for more information. If you are an individual investor, please contact your financial advisor for more information on the Calvert Unconstrained Bond Fund. www.calvert.com Calvert Investment Distributors, Inc. 4550 Montgomery Avenue Bethesda, Maryland 20814 BR10088-201411 Investment in the Calvert Unconstrained Bond Fund involves risk, including possible loss of principal invested. The Fund is subject to interest rate risk and credit risk. When interest rates rise, the value of fixed-income securities will generally fall. In addition, the credit quality of fixed-income securities may deteriorate, which could lead to default or bankruptcy of the issuer where the issuer becomes unable to pay its obligations when due. The Fund s use of derivatives such as futures, options, and swap agreements, can lead to losses, including those magnified by leverage, particularly when derivatives are used to enhance return rather than offset risk. The Fund is non-diversified and may be more volatile than a diversified fund. There is also a risk that the portfolio management practices may not achieve the desired result. For more information on any Calvert fund, please contact Calvert at 800.368.2750 for a free summary prospectus and/or prospectus. An investor should consider the investment objectives, risks, charges, and expenses of an investment carefully before investing. The summary prospectus and prospectus contain this and other information. Read them carefully before you invest or send money. Calvert mutual funds are underwritten and distributed by Calvert Investment Distributors, Inc., member, FINRA, and subsidiary of Calvert Investments, Inc. 800.368.2750. Calvert Investment Management, Inc. serves as the investment advisor and provides sustainability research for the Calvert mutual funds and institutional investment strategies.