0000319676 2012-05-01 2013-04-30 0000319676 ctfr:S000005140Member 2012-05-01 2013-04-30 0000319676 ctfr:S000005140Member ctfr:C000014074Member 2012-05-01 2013-04-30 0000319676 ctfr:S000005140Member rr:AfterTaxesOnDistributionsMember ctfr:C000014074Member 2012-05-01 2013-04-30 0000319676 ctfr:S000005140Member rr:AfterTaxesOnDistributionsAndSalesMember ctfr:C000014074Member 2012-05-01 2013-04-30 0000319676 ctfr:S000005140Member ctfr:BarclaysMunicipalBondIndexMember 2012-05-01 2013-04-30 0000319676 ctfr:S000005140Member ctfr:LipperGeneralAndInsuredMunicipalDebtFundsAverageMember 2012-05-01 2013-04-30 0000319676 ctfr:S000005138Member 2012-05-01 2013-04-30 0000319676 ctfr:S000005138Member ctfr:C000014072Member 2012-05-01 2013-04-30 0000319676 ctfr:S000005138Member ctfr:LipperTaxExemptMoneyMarketFundsAverageMember 2012-05-01 2013-04-30 pure iso4217:USD 2013-04-30 485BPOS CALVERT TAX FREE RESERVES 0000319676 2013-04-29 2013-04-30 false 2012-12-31 <b>CALVERT TAX-FREE BOND FUND</b><br/><br/>Ticker: CTTLX <b>INVESTMENT OBJECTIVE</b> The Fund seeks to earn the highest level of interest income, exempt from federal income taxes, as is consistent with prudent investment management, preservation of capital, and the quality and maturity characteristics of the Fund. This objective may be changed by the Fund’s Board of Trustees without shareholder approval. <b>FEES AND EXPENSES OF THE FUND</b> This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $50,000 in Calvert mutual funds that are not money market funds. More information about these and other discounts is available from your financial professional and under “Reduced Sales Charges” on page 12 of this Prospectus, and under “Method of Distribution” on page 22 of the Fund’s Statement of Additional Information (“SAI”). <b>Shareholder Fees</b> (fees paid directly from your investment) <div style="display:none">~ http://www.calvert.com/role/ScheduleShareholderFeesCalvertTaxFreeBondFund column period compact * ~</div> <b>Annual Fund Operating Expenses</b> (expenses that you pay each year as a %<br/>of the value of your investment) <div style="display:none">~ http://www.calvert.com/role/ScheduleAnnualFundOperatingExpensesCalvertTaxFreeBondFund column period compact * ~</div> <b>Example</b> This example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The example assumes that:<ul type="square"><li style="margin-left:-20px">you invest $10,000 in the Fund for the time periods indicated;</li><li style="margin-left:-20px">your investment has a 5% return each year; and</li><li style="margin-left:-20px">the Fund’s operating expenses remain the same.</li></ul>Although your actual costs may be higher or lower, under these assumptions your costs would be: <div style="display:none">~ http://www.calvert.com/role/ScheduleExpenseExampleTransposedCalvertTaxFreeBondFund column period compact * ~</div> <div style="display:none">~ http://www.calvert.com/role/ScheduleExpenseExampleNoRedemptionTransposedCalvertTaxFreeBondFund column period compact * ~</div> <b>Portfolio Turnover</b> The Fund pays transaction costs, such as commissions, when it buys and sells securities (“turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the “Example”, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 35% of its portfolio’s average value. <b>INVESTMENTS, RISKS AND PERFORMANCE<br/><br/>Principal Investment Strategies</b> Under normal market conditions, at least 80% of the income from the Fund will be exempt from federal income tax.<br/><br/>The Fund typically invests at least 65% of its net assets in investment grade, U.S. dollar-denominated debt securities, as assessed at the time of purchase. A debt security is investment grade when assigned a credit quality rating of BBB- or higher by Standard & Poor's Ratings Services or an equivalent rating by another nationally recognized statistical rating organization (''NRSRO"), including Moody's Investors Service or Fitch Ratings, or if unrated, considered to be of comparable credit quality by the Fund's Advisor. The Advisor looks for securities with strong credit quality that are attractively priced in various maturity ranges. To the extent it may do so consistent with its investment objective, the Fund follows a strategy to also seek to provide a competitive rate of total return. The Fund may invest in securities without limitation as to their maturity or duration, and there is no upper or lower limit on the Fund's average maturity or average duration. At the sole discretion of the Fund's portfolio manager, the Fund may seek out attractive investment opportunities across the yield curve based upon the evaluation of then-prevailing and anticipated economic, financial and business conditions.<br/><br/>The Fund is non-diversified, which means it may invest more of its assets in a smaller number of issuers than a diversified fund.<br/><br/>The Fund may invest in a variety of tax-exempt obligations, including tax-supported debt (general obligation bonds of state and local issuers), various types of revenue debt (transportation, housing, utilities, hospital), special tax obligations, qualified private activity bonds, municipal leases, and certificates of participation in such investments.<br/><br/>Tobacco Exclusion. The Fund seeks to avoid investing in companies classified under the tobacco industry sector of the Barclays Global Aggregate Index, the Barclays U.S. High Yield Index or the Barclays Global Emerging Market Index; or, in the opinion of the Fund's Advisor, any similar securities in the Barclays Municipal Index. <b>Principal Risks</b> You could lose money on your investment in the Fund, or the Fund could underperform, because of the risks described below. An investment in the Fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.<br/><br/>Non-Diversification Risk. Because the Fund may invest a greater percentage of its assets in a particular issuer than a diversified fund, the gains or losses on a single bond may have greater impact on the Fund than a diversified fund.<br/><br/>Bond Market Risk. The market prices of bonds held by the Fund may fall.<br/><br/>Management Risk. Individual investments of the Fund may not perform as expected, and the portfolio management practices may not achieve the desired result.<br/><br/>Credit Risk. 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. Unanticipated credit events could adversely impact net asset value ("NAV").<br/><br/>Unrated Security Risk. Unrated securities may be less liquid than rated securities determined to be of comparable quality. When the Fund purchases unrated securities, it will depend on the Advisor's analysis of credit risk without the assessment of an NRSRO.<br/><br/>The credit risk of an unrated security will vary depending on its equivalent credit quality and whether it is supported by a credit enhancement.<br/><br/>Interest Rate Risk. A change in interest rates may adversely affect the value of fixed-income securities. When interest rates rise, the value of fixed-income securities will generally fall. Longer-term securities are subject to greater interest rate risk.<br/><br/>Junk Bond Risk. Investments in junk bonds can involve a substantial risk of loss. Junk bonds are considered to be speculative with respect to the issuer's ability to pay interest and principal. These securities, which are rated below investment grade, have a higher risk of issuer default, are subject to greater price volatility and may be illiquid.<br/><br/>Municipal Bond Risk. In addition to interest rate risk and credit risk, different types of municipal bonds may be affected differently, based on many factors, including economic and regulatory developments, changes or proposed changes in the federal and state tax structure, deregulation, and court rulings. <b>Performance</b> The following bar chart and table show the Fund’s annual returns and its long-term performance, which give some indication of the risks of investing in the Fund. The bar chart shows how the performance of the Fund has varied from year to year. The table compares the Fund’s performance over time with that of a benchmark index and a peer average.<br/><br/>The Fund’s past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future. For updated performance information, visit www.calvert.com.<br/><br/>The bar chart does not reflect any sales charge that you may be required to pay upon purchase or redemption of the Fund’s shares. Any sales charge will reduce your return. <b>Calendar Year Total Returns (at NAV)</b> <div style="display:none">~ http://www.calvert.com/role/ScheduleAnnualTotalReturnsCalvertTaxFreeBondFundBarChart column period compact * ~</div> <table style="WIDTH: 6in; FONT-FAMILY: 'Times New Roman'; FONT-SIZE: 11pt" border="0" cellspacing="0"><tr><td width="54%"></td><td width="24%"></td><td width="15%"></td><td width="6%"></td></tr><tr valign="bottom"><td align="left"> </td><td align="right"><b>Quarter</b></td><td align="right"><b>Total</b></td><td align="left"> </td></tr><tr valign="bottom"><td align="left"> </td><td style="BORDER-BOTTOM: #000000 1px solid" align="right"><b>Ended</b></td><td style="BORDER-BOTTOM: #000000 1px solid" align="right"><b>Return</b></td><td style="BORDER-BOTTOM: #000000 1px solid" align="left"> </td></tr><tr><td colspan="4"></td></tr><tr valign="bottom"><td align="left">Best Quarter (of periods shown)</td><td align="right">3/31/09</td><td align="right">4.52</td><td align="left">%</td></tr><tr valign="bottom"><td align="left">Worst Quarter (of periods shown)</td><td align="right">12/31/10</td><td align="right">-4.52</td><td align="left">%</td></tr></table> <b>Average Annual Total Returns<br/>(as of 12/31/12) (with maximum<br/>sales charge deducted)</b> The average total return table shows the Fund’s returns with the maximum sales charge deducted, and no sales charge has been applied to the indices used for comparison in the table.<br/><br/>After-tax returns are calculated using the historical highest individual federal marginal income tax rates, and do not reflect the impact of state and local taxes. Actual after-tax returns depend on your tax situation and may differ from those shown. The after-tax returns shown are not relevant to you if you hold your Fund shares through a tax-deferred arrangement such as a 401(k) plan or individual retirement account. The return after taxes on distributions and sale of Fund shares may be higher than the return before taxes because the calculation assumes that shareholders receive a tax benefit for capital losses incurred on the sale of their shares. <div style="display:none">~ http://www.calvert.com/role/ScheduleAverageAnnualTotalReturnsTransposedCalvertTaxFreeBondFund column period compact * ~</div> You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $50,000 in Calvert mutual funds that are not money market funds. 50000 0.35 You could lose money on your investment in the Fund, or the Fund could underperform, because of the risks described below. Non-Diversification Risk. Because the Fund may invest a greater percentage of its assets in a particular issuer than a diversified fund, the gains or losses on a single bond may have greater impact on the Fund than a diversified fund. An investment in the Fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The following bar chart and table show the Fund’s annual returns and its long-term performance, which give some indication of the risks of investing in the Fund. The bar chart shows how the performance of the Fund has varied from year to year. The table compares the Fund’s performance over time with that of a benchmark index and a peer average. www.calvert.com The Fund’s past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future. The bar chart does not reflect any sales charge that you may be required to pay upon purchase or redemption of the Fund’s shares. Any sales charge will reduce your return. The average total return table shows the Fund’s returns with the maximum sales charge deducted, and no sales charge has been applied to the indices used for comparison in the table. After-tax returns are calculated using the historical highest individual federal marginal income tax rates, and do not reflect the impact of state and local taxes. The after-tax returns shown are not relevant to you if you hold your Fund shares through a tax-deferred arrangement such as a 401(k) plan or individual retirement account. The return after taxes on distributions and sale of Fund shares may be higher than the return before taxes because the calculation assumes that shareholders receive a tax benefit for capital losses incurred on the sale of their shares. Best Quarter (of periods shown) 2009-03-31 0.0452 Worst Quarter (of periods shown) 2010-12-31 -0.0452 0.0347 0.0239 0.0224 0.0678 0.0884 0.0308 0.0187 0.019 0.0591 0.0529 0.0326 0.0191 0.0198 0.051 0.0441 0.0477 0.022 0.0415 0.0425 0.018 -0.0518 0.095 -0.002 0.0854 0.0752 0.0375 0 -0.02 0.0064 0.0009 0.0017 0.009 463 651 855 1441 463 651 855 1441 <div style="display:none">~ http://www.calvert.com/role/ScheduleShareholderFeesMoneyMarketPortfolio column period compact * ~</div> <div style="display:none">~ http://www.calvert.com/role/ScheduleAnnualFundOperatingExpensesMoneyMarketPortfolio column period compact * ~</div> <div style="display:none">~ http://www.calvert.com/role/ScheduleExpenseExampleTransposedMoneyMarketPortfolio column period compact * ~</div> <div style="display:none">~ http://www.calvert.com/role/ScheduleAverageAnnualTotalReturnsTransposedMoneyMarketPortfolio column period compact * ~</div> <b>CALVERT TAX-FREE RESERVES MONEY MARKET PORTFOLIO</b><br/><br/><b>Class </b>(Ticker):<b>       O </b>(CTMXX) <b>INVESTMENT OBJECTIVE</b> The Fund seeks to earn the highest level of interest income, exempt from federal income taxes, as is consistent with prudent investment management, preservation of capital, and the quality and maturity characteristics of the Fund. This objective may be changed by the Fund’s Board of Trustees without shareholder approval. <b>FEES AND EXPENSES OF THE FUND </b> This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. <b>Shareholder Fees</b> (fees paid directly from your investment) <b>Annual Fund Operating Expenses</b> (expenses that you pay each year as a<br/>% of the value of your investment) <b>Example</b> This example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The example assumes that: <ul type="square"><li style="margin-left:--20px"> you invest $10,000 in the Fund for the time periods indicated; </li> <li style="margin-left:--20px"> your investment has a 5% return each year; and </li> <li style="margin-left:--20px"> the Fund’s operating expenses remain the same. </li></ul> Although your actual costs may be higher or lower, under these assumptions your costs would be: <b>INVESTMENTS, RISKS AND PERFORMANCE<br/><br/>Principal Investment Strategies</b> Under normal market conditions, at least 80% of the income from the Fund will be exempt from federal income tax.<br/><br/> The Fund invests in fixed and floating rate municipal bonds and notes, variable rate demand notes, tax-exempt commercial paper, and other high-quality, short-term municipal obligations. The<br/><br/> Advisor looks for securities with strong credit quality that are attractively priced. All investments generally must comply with applicable money market fund requirements, including Rule 2a-7 of the Investment Company Act of 1940.<br/><br/> Many of the instruments held by the fund are supported by a credit facility (to improve the credit quality) or liquidity facility (to shorten the maturity) provided by banks; thus, the Fund has an exposure to the banking industry.<br/><br/> The Fund may purchase securities that have not been rated by a nationally recognized statistical ratings organization ("NRSRO"), so long as the Advisor determines they are of comparable credit quality to rated securities permissible for the Fund. <b>Principal Risks</b> You could lose money on your investment in the Fund, or the Fund could underperform, because of the risks described below. An investment in the Fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund. <br/><br/> Income Risk. The income level of the Fund will fluctuate with changing market conditions and interest rate levels. The income the Fund receives may fall as a result of a decline in interest rates. <br/><br/> Interest Rate Risk. A change in interest rates may adversely affect the value of fixed-income securities. When interest rates rise, the value of fixed-income securities will generally fall. <br/><br/> Credit Risk. 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 seeks to minimize credit risk by investing primarily in securities that are considered to be of high quality. The Fund also limits the amount it invests in any one issuer to try to lessen its exposure to credit risk. <br/><br/> Management Risk. Individual investments of the Fund may not perform as expected, and the portfolio management practices may not achieve the desired result. <br/><br/> Municipal Bond Risk. In addition to interest rate risk and credit risk, different types of municipal bonds may be affected differently, based on many factors, including economic and regulatory developments, changes or proposed changes in the federal and state tax structure, deregulation, and court rulings. <br/><br/> Variable Rate Demand Note ("VRDN") Risk. Investments in VRDNs involve credit risk with respect to the obligor/guarantor providing the Fund with the credit and liquidity support for the tender option. While the Fund invests only in VRDNs of high-quality issuers, or which are supported by high-quality financial institutions, it is still possible that an obligor/guarantor could default on its obligations. <br/><br/> Unrated Security Risk. Unrated securities may be less liquid than rated securities determined to be of comparable quality. When the Fund purchases unrated securities, it will depend on the Advisor's analysis of credit risk without the assessment of an NRSRO. <br/><br/> The credit risk of an unrated security will vary depending on its equivalent credit quality and whether it is supported by a credit enhancement. <br/><br/> Redemption Risk. The Fund may experience heavy redemptions, particularly during periods of declining or illiquid markets, that could cause the Fund to liquidate its assets at inopportune times or at a loss or depressed value and that could affect the Fund's ability to maintain a $1.00 share price. In addition, the Fund may suspend redemptions when permitted by applicable regulations. You could lose money on your investment in the Fund, or the Fund could underperform, because of the risks described below. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund. An investment in the Fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The following bar chart and table show the Fund’s annual returns and its long-term performance, which give some indication of the risks of investing in the Fund. The bar chart shows how the performance of the Class O shares has varied from year to year. The table compares the Fund’s performance over time with that of a peer average. 800-368-2745 www.calvert.com The Fund’s past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future. <b>Performance</b> The following bar chart and table show the Fund’s annual returns and its long-term performance, which give some indication of the risks of investing in the Fund. The bar chart shows how the performance of the Class O shares has varied from year to year. The table compares the Fund’s performance over time with that of a peer average. <br/><br/>The Fund’s past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future. For updated performance information, visit www.calvert.com. <b>Calendar Year Total Returns</b> <b>Average Annual Total Returns<br/>(as of 12/31/12)</b> For current yield information, call 800-368-2745, or visit Calvert’s website at www.calvert.com. <div style="display:none">~ http://www.calvert.com/role/ScheduleExpenseExampleNoRedemptionTransposedMoneyMarketPortfolio column period compact * ~</div> <div style="display:none">~ http://www.calvert.com/role/ScheduleAnnualTotalReturnsMoneyMarketPortfolioBarChart column period compact * ~</div> Best Quarter (of periods shown) 2007-06-30 0.0078 Worst Quarter (of periods shown) 2011-03-31 0 <table style="WIDTH: 6in; FONT-FAMILY: 'Times New Roman'; FONT-SIZE: 11pt" border="0" cellspacing="0"><tr><td width="54%"></td><td width="24%"></td><td width="15%"></td><td width="6%"></td></tr><tr valign="bottom"><td align="left"> </td><td align="right"><b>Quarter</b></td><td align="right"><b>Total</b></td><td align="left"> </td></tr><tr valign="bottom"><td align="left"> </td><td style="BORDER-BOTTOM: #000000 1px solid" align="right"><b>Ended</b></td><td style="BORDER-BOTTOM: #000000 1px solid" align="right"><b>Return</b></td><td style="BORDER-BOTTOM: #000000 1px solid" align="left"> </td></tr><tr><td colspan="4"></td></tr><tr valign="bottom"><td align="left">Best Quarter (of periods shown)</td><td align="right">6/30/07 </td><td align="right">0.78</td><td align="left">%</td></tr><tr valign="bottom"><td align="left">Worst Quarter (of periods shown)</td><td align="right">3/31/11 </td><td align="right">0.00</td><td align="left">%</td></tr></table> 0 0 0.0051 0 0.0022 0.0073 75 233 406 906 75 233 406 906 0.005 0.0058 0.0179 0.0281 0.0306 0.0183 0.0007 0.0001 0.0001 0.0001 0.0001 0.0001 0.0038 0.004 0.011 0.0106