See notes to financial statements.

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See notes to financial statements.

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See notes to financial statements.

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See notes to financial highlights.

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See notes to financial highlights.

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See notes to financial highlights.

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See notes to financial highlights.

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A Total expenses do not reflect amounts reimbursed and/or waived by the Advisor or reductions from expense
offset arrangements. Expenses before offsets reflect expenses after reimbursement and/or waiver by the Advisor
but prior to reductions from expense offset arrangements. Net expenses are net of all reductions and represent the
net expenses paid by the Fund.

* Total return is not annualized for periods less than one year and does not reflect deduction of any front-end or
deferred sales charge.

** Portfolio turnover is not annualized for periods less than one year.

# From November 29, 2010 inception.

(a) Annualized.

(z) Per share figures are calculated using the Average Shares Method.

See notes to financial statements.

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EXPLANATION OF FINANCIAL TABLES

SC HEDULE OF I N VESTMENTS

The Schedule of Investments is a snapshot of all securities held in the fund at their market value, on the last day of the reporting period. Securities are listed by asset type (e.g., common stock, corporate bonds, U.S. government obligations) and may be further broken down into sub-groups and by industry classification.

ST ATEMENT OF A S SETS AND L I ABILITIES

The Statement of Assets and Liabilities is often referred to as the fund’s balance sheet. It lists the value of what the fund owns, is due and owes on the last day of the reporting period. The fund’s assets include the market value of securities owned, cash, receivables for securities sold and shareholder subscriptions, and receivables for dividends and interest payments that have been earned, but not yet received. The fund’s liabilities include payables for securities purchased and shareholder redemptions, and expenses owed but not yet paid. The statement also reports the fund’s net asset value (NAV) per share on the last day of the reporting period. The NAV is calculated by dividing the fund’s net assets (assets minus liabilities) by the number of shares outstanding. This statement is accompanied by a Schedule of Investments. Alternatively, if certain conditions are met, a Statement of Net Assets may be presented in lieu of this statement and the Schedule of Investments.

ST ATEMENT OF N E T A S SETS

The Statement of Net Assets provides a detailed list of the fund’s holdings, including each security’s market value on the last day of the reporting period. The Statement of Net Assets includes a Schedule of Investments. Other assets are added and other liabilities subtracted from the investments total to calculate the fund’s net assets. Finally, net assets are divided by the outstanding shares of the fund to arrive at its share price, or Net Asset Value (NAV) per share.

At the end of the Statement of Net Assets is a table displaying the composition of the fund’s net assets. Paid in Capital is the money invested by shareholders and represents the bulk of net assets. Undistributed Net Investment Income and Accumulated Net Realized Gains usually approximate the amounts the fund had available to distribute to shareholders as of the statement date. Accumulated Realized Losses will appear as negative balances. Unrealized Appreciation (Depreciation) is the difference between the market value of the fund’s investments and their cost, and reflects the gains (losses) that would be realized if the fund were to sell all of its investments at their statement-date values.

ST ATEMENT OF O P ERATIONS

The Statement of Operations summarizes the fund’s investment income earned and expenses incurred in operating the fund. Investment income includes dividends earned from stocks and interest earned from interest-bearing securities in the fund. Expenses

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incurred in operating the fund include the advisory fee paid to the investment advisor, administrative services fees, distribution plan expenses (if applicable), transfer agent fees, shareholder servicing expenses, custodial, legal, and audit fees, and the printing and postage expenses related to shareholder reports. Expense offsets (fees paid indirectly) are also shown. Credits earned from offset arrangements are used to reduce the fund’s expenses. This statement also shows net gains (losses) realized on the sale of investments and the increase or decrease in the unrealized appreciation (depreciation) on investments held during the period.

ST ATEMENT OF C H ANGES IN N E T A S SETS

The Statement of Changes in Net Assets shows how the fund’s total net assets changed during the two most recent reporting periods. Changes in the fund’s net assets are attributable to investment operations, distributions and capital share transactions.

The Operations section of the report summarizes information detailed in the Statement of Operations. The Distribution section shows the dividend and capital gain distributions made to shareholders. The amounts shown as distributions in this section may not match the net investment income and realized gains amounts shown in the Operations section because distributions are determined on a tax basis and certain investments or transactions may be treated differently for financial statement and tax purposes. The Capital Share Transactions section shows the amount shareholders invested in the fund, either by purchasing shares or by reinvesting distributions, and the amounts redeemed. The corresponding numbers of shares issued, reinvested and redeemed are shown at the end of the report.

FI NANCIAL H I GHLIGHTS

The Financial Highlights table provides a per-share breakdown per class of the components that affect the fund’s net asset value for current and past reporting periods. The table provides total return, total distributions, expense ratios, portfolio turnover and net assets for the applicable period. Total return is a measure of a fund’s performance that encompasses all elements of return: dividends, capital gain distributions and changes in net asset value. Total return is the change in value of an investment over a given period, assuming reinvestment of any dividends and capital gain distributions, expressed as a percentage of the initial investment. Total distributions include distributions from net investment income and net realized gains. Long-term gains are earned on securities held in the fund more than one year. Short-term gains, on the sale of securities held less than one year, are treated as ordinary dividend income for tax purposes. The expense ratio is a fund’s cost of doing business, expressed as a percentage of net assets. These expenses directly reduce returns to shareholders. Portfolio turnover measures the trading activity in a fund’s investment portfolio –how often securities are bought and sold by a fund. Portfolio turnover is affected by market conditions, changes in the size of the fund, the nature of the fund’s investments and the investment style of the portfolio manager.

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PROXY VOTING

The Proxy Voting Guidelines of the Calvert Funds that the Fund uses to determine how to vote proxies relating to portfolio securities are provided as an Appendix to the Fund’s Statement of Additional Information. The Statement of Additional Information can be obtained free of charge by calling the Fund at 1-800-368-2745, by visiting the Calvert website at www.calvert.com; or by visiting the SEC’s website at www.sec.gov.

Information regarding how the Fund voted proxies relating to portfolio securities during the most recent 12-month period ended June 30 is available on the Fund’s website at www.calvert.com and on the SEC’s website at www.sec.gov.

AVAILABILITY OF QUARTERLY PORTFOLIO HOLDINGS

The Fund files its complete schedule of portfolio holdings with the SEC for the first and third quarters of each fiscal year on Form N-Q. The Fund’s Form N-Q is available on the SEC’s website at www.sec.gov. The Fund’s Form N-Q may be reviewed and copied at the SEC’s Public Reference Room in Washington, DC; information on the operation of the Public Reference Room may be obtained by calling 1-800-SEC-0330.

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*The address of Trustees/Directors and Officers is 4550 Montgomery Avenue, Suite 1000N, Bethesda, Maryland 20814, except Mr. Silby’s address is 1715 18th Street, N.W., Washington, DC 20009. Ms. Krumsiek is an interested person of the Fund since she is an officer and director of the Fund’s advisor and certain affiliates. Mr. Silby is an interested person of the Fund since he is a director of the parent company of the Fund’s advisor.

Additional information about the Fund’s Trustees/Directors can be found in the Statement of Additional Information (SAI). You can get a free copy of the SAI at www.calvert.com, or by contacting your broker, or the Fund at 1-800-368-2745.

www calvert. com CALVERT SMALL CAP FUND ANNUAL REPORT (UNAUDITED) 54

To Open an Account
800-368-2748

Yields and Prices
Calvert Information Network
(24 hours, 7 days a week)
800-368-2745

Service for Existing Account
Shareholders: 800-368-2745
Brokers: 800-368-2746

TDD for Hearing Impaired
800-541-1524

Branch Office
4550 Montgomery Avenue
Suite 1000 North
Bethesda, Maryland 20814

Registered, Certified
or Overnight Mail
Calvert Investments
c/o BFDS,
330 West 9th Street
Kansas City, MO 64105

Web Site
www.calvert.com

Principal Underwriter
Calvert Investment Distributors, Inc.
4550 Montgomery Avenue
Suite 1000 North
Bethesda, Maryland 20814

This report is intended to provide fund information to shareholders. It is not authorized for distribution to prospective investors unless preceded or accompanied by a prospectus.

Note: The information on our website is not incorporated by reference into this report; our website address is included as an inactive textual reference only.

Investors should carefully consider the investment objectives, risks, charges and expenses of the Calvert Funds. This and other important information is contained in the fund’s summary prospectus and prospectus, which can be obtained from your financial professional and should be read carefully before investing. You may also call Calvert at 800/368-2745 or visit www. calvert.com.

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Just go to www.calvert.com . If you already have an online account at Calvert, click on My Account, and select the documents you would like to receive via e-mail.

If you’re new to online account access, click on Login/Register to open an online account. Once you’re in, click on the E-delivery sign-up at the bottom of the Account Portfolio page and follow the quick, easy steps. Note: if your shares are not held directly at Calvert but through a brokerage firm, you must contact your broker for electronic delivery options available through their firm.

Dear Shareholder:

Stock markets ended the 2012 annual reporting period sharply higher as the Standard & Poor’s (S&P) 500 Index returned 30.20% versus 1.14% for the 12 months through September 30, 2011. While the two periods shared many commonalities--such as a softening of economic indicators, mounting concerns about sovereign debt in the eurozone, and relatively strong corporate profits--there were some key differences.

Financial markets around the world breathed a sigh of relief after the European Central Bank committed to saving the euro this summer and offered to support the debt markets for any euro member government seeking a new financial bailout. And while the disasters in Japan and strife in the Middle East and North Africa weighed heavily on investor confidence last year, uncertainty closer to home rattled investors this year, primarily as a result of the presidential election and looming “fiscal cliff” in January 2013 that could raise taxes for many Americans. The good news is both situations should see some resolution by the end of 2012.

The U.S. economy’s relative strength was also more evident in this annual reporting period. The divergence with foreign stock market returns widened as the S&P 500 Index more than doubled the 14.33% return of the MSCI EAFE Index for the 12-month period ending September 30, 2012. In the 12 months ending September 30, 2011, the S&P 500 barely eked out a positive return compared with -8.94% for the MSCI EAFE for the same period.

A Truly Uneven Recovery

Within the United States, the economic recovery was also uneven, with some consumers and businesses feeling left behind in the midst of an “improving” economy. For example, growth in northeastern metropolitan areas lagged, while metro areas out west, particularly those in natural gas or high-tech centers, rebounded strongly. ¹ Also, the housing market finally turned the corner, as national home prices rose 3.6% year-over-year for the past 12 months. However, they surged 9.4% in the western U.S. while notching up only 0.9% in the northeast. ² In employment, more than 70% of jobs lost in service industries during the recession have returned, but only 15% of jobs lost in manufacturing, construction, and other goods-producing industries have come back. The differences are stark even within industries, where retail general merchandisers such as Costco recouped 92% while department stores regained just 41% of lost jobs. ³ Overall, we remain cautiously optimistic about the economic recovery ahead. As both citizens and investors, we hope that government legislators return to the negotiating table after the election and give us all the gift of more certainty before the holidays.

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Making Strides in Board Diversity

Calvert continued its advocacy efforts in many areas, including board diversity. The United Nations Gender Equality for Sustainable Business Event in March marked the two-year anniversary of the U.N.’s Women’s Empowerment Principles (WEP), which were adapted from the Calvert’s Women Principles ^® , and emphasized the business case for promoting gender equality and women’s empowerment in the workplace. Calvert also joined the newly formed WEP Leadership Group to expand implementation of the Principles.

On March 21, we testified before the Senate Democratic Steering and Outreach Committee about the importance of gender equity in economic empowerment and job creation, highlighting research showing the inclusion of women in corporate management correlates with higher shareholder value and better operating results.

Creating “The Future We Want” in Rio

Finally, I had the pleasure of representing Calvert by speaking at several events at the Rio + 20 Summit about board oversight of sustainability, social enterprise and impact investing, the role of business in promoting gender equality, the business case for the green economy, and establishing value for natural capital.

The first Earth Summit in Rio de Janeiro 20 years ago created climate and biodiversity conventions and set the stage for frameworks to address global environmental degradation, climate change, and poverty. However, global economic uncertainty weighed heavily on the Rio + 20 Summit. While negotiations continued to advance toward 2015, we’re disappointed by the lack of concrete commitments needed for substantial progress on critical sustainability issues.

However, side events sponsored by private-sector and non-governmental organizations sparked many innovative initiatives and positive outcomes. A number of major companies made significant commitments on water, energy, renewable materials, and deforestation. Corporate and investor disclosure of environmental, social, and governance (ESG) impacts took a real step forward as well. In fact, NASDAQ will now encourage companies on its exchange to report on ESG issues, or explain why they do not.

While these efforts can’t substitute for binding governmental commitments, we are happy to see so many companies and investors stepping up to the plate and believe the private sector will remain a key driver of progress on sustainability issues over the next few years.

Stay Informed in the Months Ahead

Maintaining a well-diversified mix of stocks, bonds, and cash appropriate for your goals and risk tolerance is one of the best ways to mitigate the effects of an uneven economic recovery. We also recommend discussing any changes in your financial situation with your investment advisor.

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A financial services consulting firm recently named Calvert as one of the Top Social Media Leaders in 2012 for using Facebook to share valuable content with investors and advisors. ⁴ Join the dialogue at www.facebook.com/calvert .

We also invite you to visit our website, www.calvert.com , for fund information, portfolio updates, and commentary from Calvert professionals. You can now get the same information on the go with our new iPhone ^® app, available free at iTunes.

As always, we thank you for investing with Calvert.

Barbara Krumsiek
President and CEO of Calvert Investments, Inc.
October 2012

1. Brookings Institution, Metro Monitor - September 2012, www.brookings.edu/research/ interactives/metromonitor#overall

2. Clear Capital, “June Home Prices Provide Further Evidence of Budding Recovery. Forecast Indicates Further Increases Through 2012,” July 2012 Market Report, http:// clearcapital.com/ company/MarketReport.cfm?month=July&year=2012

3. Paul Davison and Barbara Hansen, “Service Businesses Lead Uneven Jobs Recovery,” USA Today, July 15, 2012, www. usatoday.com/money/economy/story/2012-07-15/jobs-recovered/56242656/1

4. kasina ranked Calvert fifth of 53 asset management and insurance companies for using Facebook to tell a compelling brand story and share valuable content with investors and advisors. The ranking was based on kasina’s three-tier methodology that ranked firms based on content, branding, interactivity, and usability on each social platform. For more information, visit www.kasina.com.

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As always, Calvert continues to work hard to ensure you have a say in the responsible management of environmental, social, and governance (ESG) factors for the companies in which we invest. Below are highlights of our accomplishments during the reporting period.

The Future We Want

In addition to the highlights from the June Rio + 20 Summit in Rio de Janeiro mentioned in the letter from CEO and President Barbara Krumsiek, other specific accomplishments included: -- Private investors committed to investing more than $50 billion in clean energy and more than 50 governments pledged to adopt clean energy goals. These agreements are part of the Sustainable Energy for All initiative, which aims to provide electricity access to everyone on earth by 2030 and to double energy efficiency and alternative energy production.

-- The Natural Capital Declaration (NCD) was launched in Rio. It seeks to engage investors, governments, and insurers to develop tools for valuing “natural capital,” or goods and services derived from the environment, such as food, clean water, and biodiversity. Calvert is a signatory to the NCD and spoke at the launch, stressing the need for companies to disclose their use of natural resources and clarify potential impacts on local communities and Indigenous Peoples.

-- 45 CEO members of the U.N. CEO Water Mandate committed to making water use efficiency and wastewater goals for their own operations. The group will also lobby governments to include more input from grassroots and non-governmental organizations on improving water infrastructure and pricing, and increasing efficiency. Signatories include Calvert, Coca-Cola, PepsiCo, and Unilever.

-- Other corporate commitments focused on improving company operations and products.

For example, Infosys committed to sourcing 100% of its electricity from alternative energy.

Helping Companies Combat Climate Change Risks

Economic and insured losses from natural catastrophes set new records last year, driving home the very real physical climate risks for investors. Extreme weather events accounted for 90% of the disasters and eight of the 10 most costly events, causing overall losses of more than $148 billion. To that end, Calvert co-authored two reports to help companies evaluate their exposure to climate risks and protect shareholder value.

-- Oxfam America and Ceres joined us to create Physical Risks from Climate Change: A guide for companies and investors on disclosure and management of climate impacts . The guide focuses on companies in the agriculture, food and beverage, apparel, electric power, insurance, min-

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ing, oil and gas, and tourism sectors—all of which are considered highly vulnerable to climate impacts.

-- We also developed Value Chain Climate Resilience: A guide to managing climate impacts in companies and communities , a first-of-its-kind guide to help businesses assess and prepare for the risks and opportunities posed by climate change, with other leading companies from the Partnership for Resilience and Environmental Preparedness (PREP).

While written for all companies, it provides additional material for managers and executives in three highly vulnerable business sectors: food, beverage and agriculture; water and energy utilities; and general manufacturing.

Vote on Water Risks Resolution Receives Strong Support

This spring, Calvert filed 24 shareholder resolutions to keep the sustainability issues with a real impact on profits, people, and the planet front and center, including several on water-related issues. Since our last report, the resolution on water scarcity and pollution risks at Fossil was voted upon by shareholders and received 31% support.

As an apparel company, Fossil relies on water- and energy-intensive processes for producing cotton, leather, and other products. These processes can also pollute water supplies, especially in developing countries.

ESG Risks and Opportunities Facing Fiduciaries

Calvert staff advanced our advocacy goals by presenting at a number of conferences and events during the year. In June, Calvert Senior Vice President for Sustainability Research and Policy Bennett Freeman spoke at the RFK Compass Conference, which helps investors and asset owners explore the issues of fiduciary responsibility, sustainability, and investing in the current global economic environment.

The audience included a number of state treasurers and chief investment officers of pension funds, as well as other asset managers.

Mr. Freeman gave Calvert’s perspective on critical corporate responsibility risks and opportunities facing investors and companies alike. In particular, he focused on Calvert’s fund strategies with innovative sustainability themes such as Calvert Global Water Fund and Calvert Global Alternative Energy Fund.

New Standards Will Nearly Double Fuel Efficiency by 2025

Newly finalized corporate average fuel economy (CAFE) standards require car and light-duty truck efficiency to reach the equivalent of 54.5 mpg by 2025. This historic progress will benefit the environment and energy security by reducing oil consumption by an estimated 12 billion barrels while saving consumers about $1.7 trillion. The major automakers supported the new standards and have already begun work to provide more innovative, fuel-efficient, and cleaner vehicles.

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Fuel economy rules are critical for the environment and investors. In the U.S., transportation alone represents nearly 30 percent of GHGs, with about two-thirds coming from passenger cars and light-duty trucks. ¹ Furthermore, transportation emissions have grown faster than any other economic sector since 1990. ² Yet before 2010, the standards had not been changed for decades.

Calvert has long advocated for higher standards that we believe will help American automakers become more competitive. Higher standards will also boost U.S. policy efforts to mitigate climate change, as more than 90% of a vehicle’s contribution to climate change through greenhouse gas emissions (GHGs) is related to fuel consumption. ³ We have made this case in public testimony to Environmental Protection Agency (most recently in support of California’s Advanced Clean Cars Program), meetings with Obama administration officials, dialogues with the auto industry, and the media. We will continue to support greater vehicle efficiency, as well as the move towards lower-carbon fuels and other environmental objectives, in our on-going engagements with leading automakers and in public policy settings.

In the News

Finally, we just want to mention that several media venues also featured Calvert Global Water Fund in recent months, including a May article “Fund Makes Waves with Water Stocks” on Dow Jones Newswires and a September article “From Red to Blue” in Financial Advisor .

1. ACEEE, Automobiles and the Environment, www.greenercars.org/guide_environment.htm

2. NHTSA,EPA/NHTSA Fact Sheet on Rulemaking, www.nhtsa.gov/staticfiles/rulemaking/pdf/cafe/
CAFE_2014-18_Trucks_FactSheet-v1.pdf

3. Environmental Protection Agency, Greenhouse Gas Emissions from the U.S. Transportation Sector,
www.epa.gov/otaq/climate/420r06003.pdf

As of September 30, 2012, the Funds did not hold Coca-Cola, PepsiCo, Unilever, Infosys, or Fossil. All
holdings are subject to change without notice.

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For the 12-month period ended September 30, 2012, Calvert Global Alternative Energy Fund Class A shares (at NAV) returned -3.27% compared with -10.78% for the Ardour Global Alternative Energy Index (Composite). The Fund fared better than the benchmark due to stock selection, although sector allocation added value as well.

Investment Climate

Most of the major global equity markets (except Japan) earned double-digit percentage returns over the period, both in local currency and in U.S. dollars. However, this positive backdrop for equities did not help the renewable energy sector, where a number of head-winds hampered progress.

Without a doubt, the eurozone sovereign debt crisis was a dominant force in fueling market volatility. One crisis after another rocked global financial markets, as a number of countries on the periphery of Europe struggled to fund their excess debt. This did not help the Fund, given its relatively high weighting in the region, specifically in the southern euro countries. The Spanish and Italian indices were among the worst-performing equity indi-

* Investment performance/return at NAV does not reflect the deduction of the Fund’s maximum
4.75% front-end sales charge or any deferred sales charge.

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ces during the period. Although the bulk of our holdings in Iberia and Italy generate the majority of their sales outside the Mediterranean region, they nevertheless struggled.

However, the markets--including alternative energy stocks--responded more positively when European Union leaders agreed to lend bailout funds directly to troubled banks of member countries in June. The announcement of the European Central Bank’s (ECB) willingness to buy unlimited amounts of bonds from periphery countries, effectively removing the possibility of a sovereign default, also prompted a positive response. However, the extent and severity of the conditions the ECB will impose on those countries remains an issue.

Global economic news was mixed throughout the reporting period. Although employment was a growing concern, the U.S. economy held up reasonably well and the Federal Reserve’s latest round of quantitative easing improved market sentiment. In contrast, the eurozone fell back into negative growth. Also, the lack of growth in relatively debt-free emerging markets disappointed--China’s ability to avoid a hard landing was of particular concern. On the whole, authorities reacted accordingly by easing monetary policy but markets remained frustrated that these moves may not be sufficient.

The corporate sector demonstrated continued strength. Companies in general had very strong cash balances, which they put to work through M&A activity, dividend increases, and share buybacks. This proactive cash distribution was well received by the markets. However, companies operating in the renewable energy space seek to raise funds, not distribute them, which continued to be a negative for these companies.

Portfolio Strategy

While stock selection was the primary driver of the Fund’s relative performance, sector positioning added value as well. We trimmed weightings in Solar and Wind during the period. These continue to be pivotal parts of the Fund and we believe these two sub-sectors are best positioned to compete with traditional forms of energy over the long term. However, current sentiment toward them is weak, with a number of headwinds causing investor uncertainty.

Within Solar, we favor Canadian Solar and low-cost Chinese players such as Trina Solar, which are well-positioned to benefit from strong local demand and increasing global market share. We believe further rationalization of capacity in the market is necessary and expect market leaders with excellent cost structures to increase share as the industry continues to consolidate.

In Wind, we have retained core holdings in wind farm operators with strong balance sheets not exposed to merchant pricing in the United States. We continue to hold Iberian wind farm operators, despite noise surrounding imminent energy sector reform. Recent actions by Spanish and Portuguese governments removed a significant headwind for renewable energy and utility companies in this region. We also believe these stocks are attractively priced and already reflect the risks of higher generation taxes. We favor Chinese wind farm operators such as China Longyuan and China Suntien Energy, both of which enjoy reasonable financing costs and geographically diverse asset pipelines.

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Meanwhile, we built the position in Smart Technologies, which offers exposure to several secular growth themes such as the roll-out of smart metering technology and the integration of the European electrical grid. In fact, our preferred growth markets are smart metering, cabling, and storage solutions--all of which are essential in facilitating the long-term deployment of renewable energy.

Prysmian and Itron are two Smart Technology holdings that contributed to performance. Prysmian gained 38% on positive earnings and strong contract wins in its underground and submarine cabling business. Itron rose more than 45% due to positive earnings and outlook statements throughout the reporting period. ¹ It also finalized the acquisition of SmartSynch, which should complement current offerings and help win more contracts. SIG, a leading supplier of insulation and roofing products, benefitted from the eurozone’s improved outlook.

We also increased our position in Cooper Industries, a leading U.S. industrial player with exposure to the transmission and distribution, smart grid, and energy efficiency lighting markets. Cooper was the the largest Fund holding as of September 30, 2012.

We added to Biomass, based on our strong conviction for specific companies, and it is now the Fund’s second largest sub-sector weighting. Along with a dominant position in the U.S. waste-to-energy market, Covanta benefits from strong free cash flow generation and a highly contracted revenue stream. We also favor cellulosic ethanol company Novozymes, which we believe offers attractive long-term growth prospects and a robust margin outlook.

*Calvert Global Alternative Energy Fund first offered Class Y shares on July 29, 2011. Performance prior to that date reflects the performance of Class A shares at net asset value (NAV). Actual Class Y share performance would have been different.

But the Fund’s best performer was waste-to-energy company China Everbright, as a recent rate hike and strong demand

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Growth of $10,000

The graph below shows the value of a hypothetical $10,000 investment in the Fund over the past 10 fiscal year periods or since inception (for funds without 10-year records). The results shown are for Classes A and I shares and reflect the deduction of the maximum front-end sales charge of 4.75%, and assume the reinvestment of dividends. The result is compared with benchmarks that include a broad based market index and a Lipper peer group average. Market indexes are unmanaged and their results do not reflect the effect of expenses or sales charges. The Lipper average reflects the deduction of the category’s average front-end sales charge. The value of an investment in a different share class would be different.

All performance data shown, including the graph above and the adjacent table, represents past performance, does not guarantee future results, assumes reinvestment of dividends and distributions and does not reflect the deduction of taxes that a shareholder would pay on the Fund’s distributions or the redemption of the Fund shares. All performance data reflects fee waivers and/or expense limitations, if any are in effect; in their absence performance would be lower. See Note B in Notes to Financial Statements. The investment return and principal value of an investment will fluctuate so that an investor’s shares, when redeemed, may be worth more or less than their original cost. Current performance may be lower or higher than the performance data quoted; for current performance data visit www.calvert.com. The gross expense ratio from the current prospectus for Class A shares is 2.28%. This number may differ from the expense ratio shown elsewhere in this report because it is based on a different time period and, if applicable, does not include fee or expense waivers. Performance data quoted already reflects the deduction of the Fund’s operating expenses.

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pushed gains past 100%. Cosan was another top performer, as strong quarterly numbers and an upbeat outlook statement generated returns of more than 70% for Brazil’s largest ethanol and sugar producer.

The strategic decision to reduce allocations to Solar and Wind proved beneficial. The Fund is now underweight Solar but broadly neutral versus the benchmark in Wind. Key positives were the strong returns from the Biomass and Smart Technologies sectors.

Outlook

Markets have been dominated in recent months by fiscal and political issues and the strongly positive actions taken by central banks. In Europe, policymakers have made considerable strides since the European Union summit at the end of June. But the crisis is far from over and more twists and turns are expected before this ceases to be an important market issue.

In the United States, markets are focused on the forthcoming elections as well as the “fiscal cliff” scheduled for January 1, when the economy will be hit by significant tax increases and spending cuts unless Congress acts to prevent this. As a counterbalance, the Federal Reserve’s significant quantitative easing measures should help spur growth.

Meanwhile, emerging markets are grappling with slowing growth, albeit from relatively high levels. Authorities in these economies are expected to announce further easing measures to promote growth.

M&A activity has not been a prominent feature within the alternative energy sector and the emergence of some deals over the past few months bodes well for the sector. The rally after a German smart metering company received a bid at a 43% premium to its average trading price highlights the valuation discount that currently exists in the sector.

Overall, with equities posting strong double-digit percentage returns for the year to date, range trading is likely to occur until year-end as markets wait for evidence of an upturn in fundamentals into 2013.

October 2012

1. Individual security returns reflect total returns for period held in portfolio.

As of September 30, 2012, the following companies represented the following percentages of Fund net
assets: Canadian Solar 0.65%, Trina Solar 1.42%, China Longyuan 2.82%, China Suntien 2.36%,
Prysmian 3.45%, Itron 5.03%, SIG 2.58%, Cooper Industries 5.07%, Covanta 3.90%, Novozymes
3.30%, China Everbright 2.77%, and Cosan 3.63%. Holdings are subject to change.

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Calvert Global Water Fund Class A Shares (at NAV) returned 25.16% for the 12-month period ended September 30, 2012, versus 22.45% for the S-Network Global Water Index. The outperformance was primarily from stock selection.

Investment Climate

Most of the major global equity markets (except Japan) earned double-digit percentage returns over the period, both in local currency and in U.S. dollars. This positive backdrop for equities benefitted performance of water-related stocks.

Without a doubt, the eurozone sovereign debt crisis was a dominant force in fueling market volatility. One crisis after another rocked global financial markets, as a number of countries on the periphery of Europe struggled to fund their excess debt. However, the markets responded more positively when European Union leaders agreed to lend bail-out funds directly to troubled banks of member countries in June.

The announcement of the European Central Bank’s (ECB) willingness to buy unlimited amounts of bonds from periphery countries, effectively removing the possibility of a sover-

* Investment performance/return at NAV does not reflect the deduction of the Fund’s maximum 4.75% front-end sales charge or any deferred sales charge.

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eign default, also prompted a positive response. However, the extent and severity of the conditions the ECB will impose on those countries remains an issue.

Global economic news was mixed throughout the year. Although employment was a growing concern, the U.S. economy held up reasonably well and the Federal Reserve’s latest round of quantitative easing improved market sentiment. In contrast, the euro-zone fell back into negative growth. Also, the lack of growth in relatively debt-free emerging markets disappointed--China’s ability to avoid a hard landing was of particular concern. On the whole, authorities reacted accordingly by easing monetary policy but markets remained frustrated that these moves may not be sufficient.

The corporate sector demonstrated continued strength. Companies in general had very strong cash balances, which they put to work through M&A activity, dividend increases, and share buybacks. This proactive use was well received by the markets.

Portfolio Strategy

While stock selection was the primary driver of the Fund’s outperformance, there was added value in the Fund’s sector positioning as well. During the reporting period, we transitioned the Fund from a defensive position, with a high weighting in regulated Utilities, toward the cyclically oriented Infrastructure sub-sector, which has risk-reward opportunities we believe are more attractive.

Our high conviction in Water Infrastructure is driven by a unique valuation anomaly between Infrastructure and Utilities, demand for water infrastructure products in long-cycle industrial projects, strength in other underlying end-markets, and good visibility in sales growth over the next few years. Infrastructure now accounts for almost 50% of the portfolio and this positioning is the principal reason behind the Fund’s outperformance of the benchmark, with notable returns coming from Flowserve and Sulzer. Recent results from these pump companies only bolstered our conviction, with strong growth in July sales and orders and positive management commentary about bidding activity.

Sulzer was a new holding this year, as were Gardner Denver and SPX. These reflect our focus on end markets that tend to rebound toward the end of an economic recovery, where we believe significant growth potential exists. In fact, more than two-thirds of the Water Infrastructure sub-sector is now devoted to these businesses, which are mostly pump companies with large backlogs.

The Utilities sub-sector has gone from the largest sub-sector holding at the end of September 2011 to the smallest one at the end of September 2012. Along the way, we trimmed holdings in regulated utilities such as United Utilities, Severn Trent, and American Water Works. We also exited positions in Pennon Group and Northumbrian Water, the latter following completion of its acquisition.

We believe that Utilities in both regulated and emerging markets are now fairly valued and have only modest upside potential. However, as seen in recent months, these stocks are still a valuable diversifier and tend to do exceptionally well in risk-averse periods. Nevertheless, we were able to extract some strong performances by increasing exposure to emerging markets, mostly within the Utilities sub-sector. Notable positive contribu-

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tors included Beijing Enterprises (purchased in October 2011), Manila Water, and China Everbright.

Our weighting in Water Technology has been relatively stable. In general, our holdings had very strong balance sheets, defensible market leadership positions, and strong free cash flow. We added to companies like Kurita Water and Calgon Carbon, which, in our opinion, offer stable earnings and below-market risk and present more attractive defensive options than regulated Utilities.

We also continue to invest in Technology companies representing multiple investment themes dependent on strong market tailwinds--such as ballast water treatment and smart meters, as well as company-specific drivers. M&A is a strong feature of this sub-sector as well, boosting stocks such as metering company Elster, one of the Fund’s largest holdings and target of a bid from U.K. private equity group Melrose, in June.

Outlook

Markets have been dominated in recent months by fiscal and political issues and the strongly positive actions taken by central banks. In Europe, policymakers have made considerable strides since the European Union summit at the end of June. But the crisis is far from over and more twists and turns are expected before this ceases to be an important market issue.

In the United States, markets are focused on the forthcoming elections as well as the “fiscal cliff” scheduled for January 1, when the economy will be hit by significant tax increases and spending cuts unless Congress acts to prevent this. As a counterbalance, the Federal Reserve’s significant quantitative easing measures should help spur growth.

We believe the U.S. residential housing market is starting to turn a corner. Housing data from existing home sales to housing permits has been positive this year. Municipal bond issuance above the five-year averages and rebounding tax receipt data supports an improvement in municipal spending from current levels. Companies also say they’re starting to see more replacement work as opposed to repair and maintenance.

Meanwhile, emerging markets are grappling with slowing growth--albeit from relatively high levels. Authorities in these economies are expected to announce further easing measures to promote growth.

With equities posting strong double-digit percentage returns year to date, range trading is likely to occur until year-end as markets wait for evidence of an upturn in fundamentals into 2013.

October 2012

As of September 30, 2012, the following companies represented the following percentages of Fund net assets: Flowserve 5.30%, Sulzer 3.52%, Gardner Denver 4.04%, SPX 6.11%, United Utilities 3.74%, Severn Trent 2.48%, American Water Works 1.04%, Pennon Group 0%, Northumbrian Water 0%, Beijing Enterprises 2.22%, Manila Water 1.53%, China Everbright 1.33%, Kurita Water 6.20%, Calgon Carbon 3.75%, and Elster 0%. Holdings are subject to change.

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G rowth of $10,000

The graph below shows the value of a hypothetical $10,000 investment in the Fund over the past 10 fiscal year periods or since inception (for funds without 10-year records). The results shown are for Classes A, C and Y shares and reflect the deduction of the maximum front-end Class A sales charge of 4.75%, or deferred sales charge, as applicable and assume the reinvestment of dividends. The result is compared with benchmarks that include a broad based market index and a Lipper peer group average. Market indexes are unmanaged and their results do not reflect the effect of expenses or sales charges. The Lipper average reflects the deduction of the category’s average front-end sales charge. The value of an investment in a different share class would be different.

All performance data shown, including the graph above and the adjacent table, represents past performance, does not guarantee future results, assumes reinvestment of dividends and distributions and does not reflect the deduction of taxes that a shareholder would pay on the Fund’s distributions or the redemption of the Fund shares. All performance data reflects fee waivers and/or expense limitations, if any are in effect; in their absence performance would be lower. See Note B in Notes to Financial Statements. The investment return and principal value of an investment will fluctuate so that an investor’s shares, when redeemed, may be worth more or less than their original cost. Current performance may be lower or higher than the performance data quoted; for current performance data visit www.calvert.com. The gross expense ratio from the current prospectus for Class A shares is 2.31%. This number may differ from the expense ratio shown elsewhere in this report because it is based on a different time period and, if applicable, does not include fee or expense waivers. Performance data quoted already reflects the deduction of the Fund’s operating expenses.

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SHAREHOLDER EXPENSE EXAMPLE

As a shareholder of the Fund, you incur two types of costs: (1) transaction costs, including sales charges and redemption fees; and (2) ongoing costs, including management fees; distribution (12b-1) fees; and other Fund expenses. This Example is intended to help you understand your ongoing costs (in dollars) of investing in the Fund and to compare these costs with the ongoing costs of investing in other mutual funds.

This Example is based on an investment of $1,000 invested at the beginning of the period and held for the entire period (April 1, 2012 to September 30, 2012).

Actual Expenses

The first line of the table below provides information about actual account values and actual expenses. You may use the information in this line, together with the amount you invested, to estimate the expenses that you paid over the period. Simply divide your account value by $1,000 (for example, an $8,600 account value divided by $1,000 = 8.6), then multiply the result by the number in the first line under the heading entitled “Expenses Paid During Period” to estimate the expenses you paid on your account during this period.

Hypothetical Example for Comparison Purposes

The second line of the table below provides information about hypothetical account values and hypothetical expenses based on the Fund’s actual expense ratio and an assumed rate of return of 5% per year before expenses, which is not the Fund’s actual return. The hypothetical account values and expenses may not be used to estimate the actual ending account balance or expenses you paid for the period. You may use this information to compare the ongoing costs of investing in the Fund and other funds. To do so, compare the 5% hypothetical example with the 5% hypothetical examples that appear in the shareholder reports of the other funds.

Please note that the expenses shown in the table are meant to highlight your ongoing costs only and do not reflect any transactional costs, such as sales charges (loads), or redemption fees. Therefore, the second line of the table is useful in comparing ongoing costs only, and will not help you determine the relative total costs of owning different funds. In addition, if these transactional costs were included, your costs would have been higher.

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*Expenses are equal to the Fund’s annualized expense ratio of 1.85%, 2.85%, 1.40%, and 1.60% for Class A, Class C, Class I, and Class Y, respectively, multiplied by the average account value over the period, multiplied by 183/366 (to reflect the one-half year period).

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