Experience and Foresight

About Calamos Investments

For over 35 years, we have helped investors like you manage and build wealth to meet their long-term individual objectives by working to capitalize on the opportunities of the evolving global marketplace. We launched our first mutual fund in 1985 and our first closed-end fund in 2002. Today, we manage five closed-end funds. Two are total-return oriented offerings, which seek current income, with increased emphasis on capital gains potential. Three are enhanced fixed income offerings, which pursue high current income from income and capital gains. Calamos Global Dynamic Income Fund (CHW) falls into this latter category. Please see page 5 for a more detailed overview of our closed-end offerings.

We are dedicated to helping our clients build and protect wealth. We understand when you entrust us with your assets, you also entrust us with your achievements, goals and aspirations. We believe we best honor this trust by making investment decisions guided by integrity, by discipline, and by our conscientious research.

We believe an active, risk-conscious approach is essential for wealth creation. In the 1970s, we pioneered strategies that seek to participate in equity market upside and mitigate some of the potential risks of equity market volatility. Our investment process seeks to manage risk at multiple levels and draws upon our experience investing through multiple market cycles.

We have a global perspective. We believe globalization offers tremendous opportunities for countries and companies all over the world. In our view, this creates significant opportunities for investors. In our U.S., global and international portfolios, we are seeking to capitalize on the potential growth of the global economy.

We believe there are opportunities in all markets. Our history traces back to the 1970s, a period of significant volatility and economic concerns. We have invested through multiple market cycles, each with its own challenges. Out of this experience comes our belief that the flipside of volatility is opportunity.

JOHN P. CALAMOS, SR.

CEO and Global Co-CIO

Dear Fellow Shareholder:

Welcome to your annual report for the 12-month period ended October 31, 2014. In this report, you will find commentary from the management team, as well as a listing of portfolio holdings, financial statements and highlights, and detailed information about the Fund’s performance and positioning. I invite you to review not only the commentary for this Fund, but also to discuss with your financial advisor if there are other Calamos Funds that could be suitable for your asset allocation.

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 Increase

During the period, CHW provided not only a steady monthly distribution but also increased the distribution in April by 13% to $0.0700 from $0.0620. The increase is a result of positioning the Fund to optimize returns in both the current and anticipated economic environments. We believe the Fund’s current annualized distribution rate, which was 9.32%* on a market price basis as of October 31, 2014, 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 environments. 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 39.)

Market Environment

During the reporting period, global equities advanced, although there was a wide variation in the performance of individual markets. The MSCI World Index, a measure of developed market equities, earned 9.25%, while the MSCI Emerging Markets Index posted a return of 0.98%. Emerging markets were hindered by concerns of higher U.S. interest rates and weaker economic data in some countries. U.S. stocks drove gains in the developed global markets, with the S&P 500 Index returning 17.27%. The U.S. convertible market captured a large measure of the U.S. stock market’s gains, with the BofA Merrill Lynch All U.S. Convertibles Index earning 13.48%.

Fixed income markets also gained, but at a more measured pace. The Barclays U.S. Aggregate Bond Index returned 4.14% for the 12-month period, with stronger performance toward the end of the period as apprehensive investors sought haven in fixed income securities. The Credit Suisse High Yield Index performed more strongly, gaining 5.54%, as investors sought yield in a low interest-rate environment.

Our Use of Leverage**

We have the flexibility to utilize leverage in this Fund. Over the long term, we believe that the judicious use of leverage provides us with opportunities to enhance total return and support the Fund’s distribution rate. Leverage strategies typically entail borrowing at short-term interest rates and investing the proceeds at higher rates of return. During the reporting period, we believed the prudent use of leverage would be advantageous given the economic environment, and more specifically, the low borrowing costs we were able to secure. Overall, the use of leverage contributed favorably to the returns of the Fund, as the performance of the Fund’s holdings exceeded the cost of borrowing.

Consistent with our focus on risk management, we have employed techniques to hedge against a rise in interest rates. We have used interest rate swaps to manage the borrowing costs associated with the Fund’s use of leverage. Interest rate swaps allow us to “lock down” an interest rate we believe to be attractive. Although rates are at historically low levels across much of the fixed income market, history has taught us that rates can rise quickly—in some cases, in a matter of months. We believe the Fund’s use of interest rate swaps is beneficial because it provides a degree of protection should a rise in rates occur. However, we will continue to assess the costs versus benefits of employing swaps as part of our leverage strategy.

Long-Term Focus

An important take-away from the past year is the benefit of maintaining a long-term focus in regard to asset allocation. Although the U.S. and global stock markets advanced overall, the period was characterized by surges in volatility and changes in market leadership. Investors who tried to time these ups and downs could well have been whipsawed—missing the upside but capturing the downside. For example, during the period, there were several sell-offs in growth sectors, as investors allowed anxiety about economic growth to overshadow fundamentals. Yet during the 12-month period, U.S. growth stocks outperformed their value counterparts, with the Russell 3000 Growth Index gaining 16.39% versus the Russell 3000 Value Index, up 15.76%.

Also, we saw lackluster performance during the reporting period in some areas of the market that we believe offer compelling long-term potential. Emerging market equities, for example, posted only small gains over the year, despite the strong demographic trends that we believe will support multi-decade investment opportunity—most notably, the rise of a global middle class.

In our view, stocks are attractively valued and have more room to advance, particularly the stocks of growth companies. By a number of our favored measures, the prices of many stocks are compelling relative to bonds and inflation. Although we expect the pace of economic growth will vary considerably from country to country, we believe stocks can benefit from moderate global economic expansion supported by highly accommodative global monetary policy. We are particularly constructive on the U.S. economy, which looks to be in the middle innings of recovery with steady GDP growth and declining unemployment. While the intentions of the Federal Reserve roiled the markets at points over the reporting period, we believe the Federal Reserve will continue to take a flexible approach, adapting its policy decisions to conditions not just in the U.S. but also in the global economy. Also, we believe that merger-and-acquisition activity and share buybacks can provide continued support to the equity market.

We believe that investors should work with their advisors to prepare for an eventual rise in interest rates. U.S. and global interest rates have stayed low for longer than many have anticipated due to a variety of factors, including accommodative policy and investors’ desire for allocations with a higher degree of perceived safety.

Convertible securities are well suited to this environment. Although we expect markets to advance and the global economy to expand, we believe volatility will likely persist due to a range of factors. Actively managed allocations that include convertibles may prove especially beneficial, because convertibles combine attributes of stocks and bonds. As a result, convertible securities have the potential to provide participation in stock market upside with potential protection if stocks experience periods of downside volatility. Convertibles

also have tended to be more resilient to rising interest rates than traditional fixed income securities—a key consideration for investors who seek to position their asset allocations ahead of a possible rising interest rate environment. We are also encouraged by issuance trends, as economic growth has historically provided a catalyst for convertible issuance.

In closing, we are honored to serve you. We recognize the trust you have in placed in us to help you achieve your financial goals. If you have any questions or would like additional information, please visit us at www.calamos.com or contact us at 800.582.6959.

Sincerely,

John P. Calamos, Sr.

CEO and Global Co-CIO,

Calamos Advisors LLC

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 S&P 500 Index is an unmanaged index generally considered representative of the U.S. stock market. The BofA Merrill Lynch All U.S. Convertibles Index represents the U.S. convertible securities market. The Barclays Capital U.S. Aggregate Bond Index is considered generally representative of the investment-grade bond market. The Credit Suisse High Yield Index is an unmanaged index of approximately 1,600 issues with an average maturity range of seven to ten years with a minimum capitalization of $75 million. The index is considered generally representative of the U.S. market for high yield bonds. The Russell 3000 Growth Index measures the performance of the broad growth segment of the U.S. equity universe. The Russell 3000 Value Index measures the performance of the broad value segment of the U.S. equity universe. The MSCI Emerging Markets Index represents equities of emerging and developing countries. 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 Asia/Pacific region. Source: Lipper

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.

GLOBAL DYNAMIC INCOME FUND (CHW)

INVESTMENT TEAM DISCUSSION

Please discuss the Fund’s strategy and portfolio 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.

In this portfolio, we are drawing upon our team’s experience in an array of asset classes. We utilize a highly flexible approach, and can invest in equities, convertible securities and high-yield securities. We also can 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. 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 with 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 gained 7.02% on a net asset value (NAV) basis for the 12-month period ended October 31, 2014. On a market price basis, the Fund returned 10.93%. As a comparison to the broader global fixed income and equity markets, the MSCI EAFE¹ Index lost 0.17% and the MSCI World Index returned 9.25% during the period. The S&P 500 Index returned 17.27% during the period.

At the end of the reporting period, the Fund’s shares traded at an 8.62% discount to net asset value, down from an 11.84% discount at the beginning of the period.

SINCE INCEPTION MARKET PRICE AND NAV HISTORY THROUGH 10/31/14

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 expectation. A fund’s NAV return measures the actual return of the individual securities in the portfolio, less fund expenses. It also measures how well a manager capitalized 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 within this Fund with the goal of providing shareholders with a consistent distribution stream. The Fund provided an improved distribution stream of income over the period. In April, we increased our monthly distributions from $0.062 per share to $0.07 per share, a 13% increase from the previous month. The Fund’s annual distribution rate was 9.32% of market price as of October 31, 2014.

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, 2014, the dividend yield of S&P 500 Index stocks averaged 2.0%. Yields also remained low within the U.S. government bond market, with the 10-year U.S. Treasury and the 30-year U.S. Treasury yielding 2.35% and 3.07%, respectively.

What factors influenced performance over the reporting period?

The Fund has the ability to invest in a range 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. Given this flexibility, we were able to increase our exposure to the equity markets by expanding our convertible holdings, which allowed us to participate in the

Fund asset allocations are based on total investments and may vary over time.