JOHN P. CALAMOS, SR.
Chairman and Global CIO

Dear Fellow Shareholder:

Welcome to your annual report for the 12-month period ended October 31, 2016. In this report, you will find commentary from the management team of the Fund, as well as a listing of portfolio holdings, financial statements and highlights, and detailed information about the Fund’s performance and positioning. I encourage you to review this information carefully.

Calamos Global Dynamic Income Fund (CHW) is an enhanced fixed income fund. We utilize dynamic asset allocation to pursue high current income, while also maintaining a focus on capital gains.

Distribution

During the period, the Fund provided a compelling monthly distribution of $0.0700 per share. We believe the Fund’s current annualized distribution rate, which was 11.73%* on a market price basis as of October 31, 2016, was very competitive, given the low interest rates in many segments of the bond market. In our view, the Fund’s distributions illustrate the benefits of a multi-asset class approach and flexible allocation strategy.

We understand that many closed-end fund investors seek steady, predictable distributions instead of distributions that fluctuate. Therefore, this Fund has a level rate distribution policy. As part of this policy, we aim to keep distributions consistent from month to month, and at a level that we believe can be sustained over the long term. In setting the Fund’s distribution rate, the investment management team and the Fund’s Board of Trustees consider the interest rate, market and economic environment. We also factor in our assessment of individual securities and asset classes. (For additional information on our level rate distribution policy, please see “The Calamos Closed-End Funds: An Overview” on page 5 and “Level Rate Distribution Policy” on page 40.)

*      Current Annualized Distribution Rate is the Fund’s most recent distribution, expressed as an annualized percentage of the Fund’s current market price per share. The Fund’s 10/14/16 distribution was $0.0700 per share. Based on our current estimates, we anticipate that approximately $0.0364 is paid from ordinary income or capital gains and that approximately $0.0336 represents a return of capital. Estimates are calculated on a tax basis rather than on a generally accepted accounting principles (GAAP) basis, but should not be used for tax reporting purposes. Distributions are subject to re-characterization for tax purposes after the end of the fiscal year. This information is not legal or tax advice. Consult a professional regarding your specific legal or tax matters. Under the Fund’s level rate distribution policy, distributions paid to common shareholders may include net investment income, net realized short-term capital gains and return of capital. When the net investment income and net realized short-term capital gains are not sufficient, a portion of the level rate distribution will be a return of capital. In addition, a limited number of distributions per calendar year may include net realized long-term capital gains. Distribution rate may vary.

Outlook

As we look to the future, our team is closely monitoring evolving geopolitical relationships, oil prices and global central bank policies. We remain highly attentive to the impact of populist crosscurrents, particularly in Europe, where several key elections are approaching.

We continue to believe the global economy is positioned for continued slow economic expansion, although the pace of growth is likely to vary among countries. In the U.S., economic growth is likely to ramp up a bit from recent levels, and our expectations for inflation have risen. As the economy continues to expand, we see an increased likelihood that the Federal Reserve Open Market Committee raises short-term interest rates. However, the aggressive quantitative easing of other global central banks is likely to limit how far interest rates can move.

As we look to the future, our team sees opportunities across a range of asset classes, with increased potential in cyclical growth areas. We believe U.S. equities can benefit from President-Elect Trump’s pro-growth stance, with corporate tax reform, individual tax reform and infrastructure spending providing support to the bull market.

However, there is considerable uncertainty surrounding many elements of the President-Elect’s vision for America and its implications for the global economy. As greater clarity emerges around fiscal and foreign policy over these next months, winners and losers will emerge. Investors should be prepared for volatility spikes and market rotation. Consequently, selectivity and attention to fundamentals remain paramount, especially given the high valuations we see in some segments of the market.

We believe the case for actively managed convertible securities is strong. It has been many years since investors contended with rising U.S. interest rates and inflation. I remember in the 1970s, and again in the 1980s, how investors were caught very much by surprise by rising rates. Although the backdrop is different now than it was in either of those periods, there are plenty of reasons for investors to revisit the interest rate exposure in their asset allocations. Historically, convertible securities have demonstrated greater resilience to rising interest rates than traditional fixed income securities, due to convertibles’ equity characteristics.

Letter to Shareholders

Conclusion

These past months should remind investors that volatility is a part of all markets, including bull markets. As importantly, we are reminded of the resilience of the markets and the global economy. In July, the UK’s vote in favor of leaving the European Union took markets by surprise, leading to a precipitous drop immediately following the result. Yet markets soon regained their equilibrium and rose higher. Similarly, many market participants were surprised by President-Elect Donald Trump’s victory but once again, the choppiness was short lived.

The start of a new year is an excellent opportunity to consult with your financial advisor, who can help ensure that your asset allocation aligns with your long-term goals and risk tolerance. As you prepare for these conversations, I invite you to visit our website, www.calamos.com. You’ll find a range of resources, including blogs and videos from our investment team and thought leadership pieces.

In closing, thank you for the trust that you have placed in us to help you achieve your financial goals. We are honored to serve you.

Sincerely,

John P. Calamos, Sr.

Founder, Chairman and Global Chief Investment Officer

Before investing, carefully consider a Fund’s investment objectives, risks, charges and expenses. Please see the prospectus containing this and other information or call 800.582.6959. Please read the prospectus carefully. Performance data represents past performance, which is no guarantee of future results. Current performance may be lower or higher than the performance quoted.

The MSCI World Index is a market-capitalization weighted index composed of companies representative of the market structure of developed market countries in North America, Europe and the Asia/Pacific region. The S&P 500 Index is an unmanaged index generally considered representative of the U.S. stock market. The MSCI Emerging Markets Index is a free float-adjusted market capitalization index considered broadly representative of emerging market equity performance. The index represents companies within the constituent emerging markets that are available to investors worldwide. The BofA Merrill Lynch All U.S. Convertibles ex-Mandatory Index represents the U.S. convertible securities market excluding mandatory convertibles. The BofA Merrill Lynch Global 300 Convertible Index is a global convertible index composed of companies representative of the market structure of countries in North America, Europe and the Asia/ Pacific region. The Credit Suisse U.S. High Yield Index is an unmanaged index of high yield debt securities. The Bloomberg Barclays U.S. Aggregate Bond Index is considered generally representative of the investment-grade bond market. Sources: Lipper, Inc.; Morningstar, Inc.

Unmanaged index returns assume reinvestment of any and all distributions and, unlike fund returns, do not reflect fees, expenses or sales charges. Investors cannot invest directly in an index. Investments in overseas markets pose special risks, including currency fluctuation and political risks. These risks are generally intensified for investments in emerging markets. Countries, regions, and sectors mentioned are presented to illustrate countries, regions, and sectors in which a fund may invest. Fund holdings are subject to change daily. The Fund is actively managed. The information contained herein is based on internal research derived from various sources and does not purport to be statements of all material facts relating to the securities mentioned. The information contained herein, while not guaranteed as to the accuracy or completeness, has been obtained from sources we believe to be reliable. There are certain risks involved with investing in convertible securities in addition to market risk, such as call risk, dividend risk, liquidity risk and default risk, that should be carefully considered prior to investing. This information is being provided for informational purposes only and should not be considered investment advice or an offer to buy or sell any security in the portfolio.

4     CALAMOS GLOBAL DYNAMIC INCOME FUND ANNUAL REPORT

In our closed-end funds, we draw upon decades of investment experience, including a long history of opportunistically blending asset classes in an attempt to capture upside potential while seeking to manage downside risk. We launched our first closed-end fund in 2002.

Closed-end funds are long-term investments. Most focus on providing monthly distributions, but there are important differences among individual closed-end funds. Calamos closed-end funds can be grouped into multiple categories that seek to produce income while offering exposure to various asset classes and sectors.

Our Level Rate Distribution Policy 

Closed-end fund investors often look for a steady stream of income. Recognizing this, Calamos closed-end funds have a level rate distribution policy in which we aim to keep monthly income consistent through the disbursement of net investment income, net realized capital gains and, if necessary, return of capital. We set distributions at levels that we believe are sustainable for the long term. Our team is focused on delivering an attractive monthly distribution, while maintaining a long-term focus on risk management. The level of the funds’ distributions can be greatly influenced by market conditions, including the interest rate environment. The funds’ distributions will depend on the individual performance of positions the funds hold, our view of the benefits of retaining leverage, fund tax considerations, and maintaining regulatory requirements.

For more information about any of these funds, we encourage you to contact your financial advisor or Calamos Investments at 800.582.6959 (Monday through Friday from 8:00 a.m. to 6:00 p.m., Central Time). You can also visit us at www.calamos.com.

For more information on our level rate distribution policy, please see page 40.

GLOBAL DYNAMIC INCOME FUND (CHW) 

INVESTMENT TEAM DISCUSSION

To provide a context for its performance, please discuss the Fund’s strategy and role within an asset allocation.

Calamos Global Dynamic Income Fund (CHW) is a global enhanced fixed-income offering that seeks to provide an attractive monthly distribution, with a secondary objective of capital appreciation. We believe it offers a diversified way to participate in the long-term potential of global markets. Like all six Calamos closed-end funds, the Fund seeks to provide a steady stream of distributions paid out monthly and invests in multiple asset classes.

In this portfolio, we draw upon our team’s wide-ranging experience in an array of asset classes. We utilize what we believe to be a highly flexible approach, and can invest in equities, convertible securities and high-yield securities. We can also employ alternative strategies such as covered call writing and convertible arbitrage. Through covered call writing, we seek to generate income by selling (“writing”) options on market indexes. In the convertible arbitrage strategy, we invest in convertible securities and short sell the convertibles’ underlying equities to generate income and hedge against risk.

We believe that this broad mandate enhances our ability to capitalize on market volatility, manage potential downside risks and generate more income versus traditional fixed-income funds. The allocation to each asset class and strategy is dynamic, and reflects our view of the economic landscape as well as the potential of individual securities. By combining asset classes and strategies, we believe that we are well positioned to generate income and capital gains. We believe the broader range of security types also provides us with increased opportunities to manage the risk and reward characteristics of the portfolio over full market cycles. We believe our exposure to the equity markets was beneficial to the overall performance of the Fund.

We invest in both U.S. and non-U.S. companies, with at least 40% of assets invested in non-U.S. companies. We emphasize companies that we see as having reliable debt servicing, respectable balance sheets, and sustainable prospects for growth. Regardless of a company’s country of domicile, we favor companies with geographically diversified revenue streams and global business strategies.

How did the Fund perform over the reporting period?

The Fund returned 2.98% on a net asset value (NAV) and 4.95% on a market price basis for the 12-month period ended October 31, 2016. As a comparison to the broader global markets, the MSCI EAFE Index declined -2.74% and the MSCI World Index returned 1.79% during the period. The S&P 500 returned 4.51% during the period.

At the end of the reporting period, the Fund’s shares traded at a 12.25% discount to NAV.

SINCE INCEPTION MARKET PRICE AND NAV HISTORY THROUGH 10/31/16

Performance data quoted represents past performance, which is no guarantee of future results. Current performance may be lower or higher than the performance quoted. The principal value of an investment will fluctuate so that your shares, when sold, may be worth more or less than their original cost. Returns at NAV reflect the deduction of the Fund’s management fee, debt leverage costs and all other applicable fees and expenses. You can obtain performance data current to the most recent month end by visiting www.calamos.com.

How do NAV and market price return differ? 

Closed-end funds trade on exchanges, where the price of shares may be driven by factors other than the value of the underlying securities. The price of a share in the market is called market value. Market price may be influenced by factors unrelated to the performance of the fund’s holdings, such as general market sentiment or future expectations. A fund’s NAV return measures the actual return of the individual securities in the portfolio, less fund expenses. It also measures how a manager was able to capitalize on market opportunities. Because we believe closed-end funds are best utilized as a long-term holding within asset allocations, we believe that NAV return is the better measure of a fund’s performance. However, when managing the fund, we strongly consider actions and policies that we believe will optimize its overall price performance and returns based on market price.

Please discuss the Fund’s distributions during the annual period. 

We employ a level rate distribution policy for this Fund with the goal of providing shareholders with a consistent distribution stream. The Fund provided a distribution stream of income over the period of $0.0700 per share. The Fund’s annual distribution rate was 11.73% of market price as of October 31, 2016.

We believe that both the Fund’s distribution rate and level remained attractive and competitive, as low interest rates limited yield opportunities in much of the marketplace. For example, as of October 31, 2016, the dividend yield of S&P 500 Index stocks averaged 2.19%. Yields also remained low within the U.S. government bond market, with 10-year U.S. Treasury and 30-year U.S. Treasury yielding 1.84% and 2.58%, respectively.

What factors influenced performance over the reporting period? 

The Fund has great flexibility in its ability to invest in a number of strategies including convertible securities, high yield, U.S. equities, international equities, as well as convertible arbitrage. This enables us to participate in a myriad of opportunities on behalf of our shareholders. As a consequence of this, we were able to increase our exposure to the equity markets by increasing our convertible holdings which, in turn, allowed us to participate in the general market upswing.

The Fund’s U.S. equity sleeve underperformed relative to the S&P 500 Index as our selection in financials, namely diversified banks, lagged relative to the Index. In addition, our selection in information technology, namely technology, hardware, storage and peripherals, detracted from performance.

Conversely, our selection in health care, namely pharmaceuticals, outperformed relative to the Index. In addition, our holdings and selection in industrials, namely aerospace and defense, contributed favorably during the period.

The Fund’s global equity sleeve outperformed relative to the MSCI World Index. Our underweight in healthcare, namely pharmaceuticals, aided performance. In addition, our selection in telecom services, namely wireless telecommunication services, proved beneficial. From a geographic standpoint, our overweight allocation to China also contributed.

Conversely, our selection in energy, namely oil and gas exploration and production, was a detractor relative to the Index. Our selection in industrials, namely construction and engineering, impeded performance. From a geographic standpoint, our underweight allocation and selection in Australia was detrimental.

The Fund’s international equity sleeve outperformed relative to the MSCI EAFE Index. Our overweight position and selection in information technology, namely internet software and services, was a source of strength relative to the Index. In addition, our selection in materials, namely gold, was helpful as was an overweight in China.

Conversely, selection in health care, namely pharmaceuticals, impeded performance relative to the MSCI EAFE Index. In addition, our selection in telecom services, specifically wireless telecom services, hindered returns.

The convertible arbitrage sleeve contributed positively for the period. Convertible arbitrage contributed positively to the portfolio’s performance as convertibles benefited from narrowing credit spreads, richening convertible valuations, and spikes in volatility that provided opportunities to rebalance our hedges. The low interest rate environment continues to present a headwind to convertible arbitrage from the standpoint of low-coupon yields and a low-interest carry on the cash received from our short equity positions.

How is the Fund positioned? 

We continue to find opportunities across asset classes. We also continue to maintain a preference for larger cap growth-oriented companies with global presence and geographically diversified revenue streams. We believe that such companies may be particularly well positioned to capitalize on global growth trends that we identify, as economic growth remains more measured in the U.S. and other developed markets. In keeping with emphasis on risk management, we continue to emphasize those companies that we believe have respectable balance sheets, good prospects for sustainable growth and reliable debt servicing.

The portfolio’s largest allocations, in absolute terms, are in the information technology consumer discretionary, industrials and financials. We believe that many information technology companies offer compelling fundamentals as well as participation in secular growth trends. In regard to consumer discretionary, we believe that companies in the sector may benefit from improving economic conditions, highlighted by higher employment and lower energy costs. We believe that financial companies will do well in a rising interest rate environment.

As noted, our pursuit of yield is informed by our risk-managed approach to total return. Reflecting this, the Fund portfolio includes a blend of high yield and investment grade credits. We have taken a very selective approach to CCC rated credits. Given our expectation that economic growth may occur in fits and starts as we move into 2017, we believe it is particularly important to favor companies that offer the best prospects for reliable debt servicing. This bodes well for us as these lower credits came under pressure, especially during the past quarter, and we avoided such difficulties.

The Fund is currently employing leverage at approximately 29%. We currently borrow through floating rate bank debt. Given low borrowing rates, this has been beneficial to the performance of the Fund. In addition, approximately 17% of our floating rate debt is hedged through interest rate swaps. This is a defensive strategy that mitigates the Fund’s overall exposure to a quick rise in short-term interest rates.

What is your outlook for the Fund? 

Although we remain positive, we expect elevated volatility to persist due to global growth concerns and central bank policies—including an uncertain Federal Reserve timeline and divergent courses among global central banks. Fiscal policy is likely to remain a focal point of market anxiety, with the uncertainty surrounding the U.S. presidential election among the factors figuring prominently in this regard.

We believe the U.S. and global economies are likely to maintain expansion over the near term. The U.S. consumer remains strong, key data points in the eurozone have shown improvement, and China has many tools at its disposal to avoid a hard landing. In our view, fiscal policy remains a headwind to more robust expansion, with overregulation among the factors challenging entrepreneurship and business growth in numerous economies, including the U.S. infrastructure development could be a growth catalyst going into 2017.

In our view, inflationary pressures may arise if the Fed sees an opportunity to raise interest rates. Meanwhile, secular themes, such as global demographic shifts and a growing global middle class, can continue to provide tailwinds for certain companies to grow in both favorable and unfavorable economic climates.

We have also seen continued issuance in the global convertible market, which is presenting additional investment opportunities that will enable us to receive income while participating in improvements in the equity markets. We believe this dynamic will offer our shareholders the income they seek in a closed-end fund vehicle, in addition to the opportunity for capital appreciation.