0001265389 pst:S000010085Member pst:C000027935Member rr:AfterTaxesOnDistributionsAndSalesMember 2011-05-05 2012-05-04 0001265389 pst:S000010084Member pst:C000027930Member rr:AfterTaxesOnDistributionsMember 2011-05-05 2012-05-04 0001265389 pst:S000010085Member pst:C000027935Member rr:AfterTaxesOnDistributionsMember 2011-05-05 2012-05-04 0001265389 pst:S000010084Member pst:C000027930Member rr:AfterTaxesOnDistributionsAndSalesMember 2011-05-05 2012-05-04 0001265389 pst:S000010085Member pst:C000027937Member 2011-05-05 2012-05-04 0001265389 pst:S000010085Member pst:BarclaysCapitalMunicipalBondIndexMember 2011-05-05 2012-05-04 0001265389 pst:S000010084Member pst:C000027931Member 2011-05-05 2012-05-04 0001265389 pst:S000010084Member pst:C000079046Member 2011-05-05 2012-05-04 0001265389 pst:S000010084Member pst:C000027933Member 2011-05-05 2012-05-04 0001265389 pst:S000010084Member pst:C000027932Member 2011-05-05 2012-05-04 0001265389 pst:S000010085Member pst:C000027936Member 2011-05-05 2012-05-04 0001265389 pst:S000010084Member pst:RussellTwoThousandGrowthIndexMember 2011-05-05 2012-05-04 0001265389 pst:S000010085Member pst:C000035677Member 2011-05-05 2012-05-04 0001265389 pst:S000010084Member pst:C000027930Member 2011-05-05 2012-05-04 0001265389 pst:S000010085Member pst:C000027935Member 2011-05-05 2012-05-04 0001265389 pst:S000010084Member 2011-05-05 2012-05-04 0001265389 pst:S000010085Member 2011-05-05 2012-05-04 0001265389 2011-05-05 2012-05-04 iso4217:USD xbrli:pure false 2012-05-04 2012-05-04 2011-12-31 Other 0001265389 PIONEER SERIES TRUST II <div>&lt;div style="display:none;"&gt;~ http://pioneerinvestments.com/role/AnnualFundOperatingExpensesPioneerAMTFreeMunicipalFund ~&lt;/div&gt;</div> <div>&lt;div style="display:none;"&gt;~ http://pioneerinvestments.com/role/AnnualFundOperatingExpensesPioneerGrowthOpportunitiesFund ~&lt;/div&gt;</div> 0.0998 -0.3705 0.4367 0.0566 0.0545 0.2223 0.0456 0.0480 0.0478 0.0520 -0.0390 0.0140 -0.1485 -0.3539 0.4301 0.2401 0.1960 0.0215 -0.0253 0.1173 2006-11-10 1996-09-30 1996-09-30 1996-09-30 1996-09-30 2000-04-30 2005-09-23 2009-08-03 1996-09-30 1996-09-30 2003-10-01 1996-09-30 1996-09-30 1996-09-30 1996-09-30 0.0369 0.1123 0.0606 0.0492 0.0542 0.0204 0.0220 0.0427 0.0447 0.0389 0.0566 0.0384 0.0378 0.0515 0.0547 -0.0283 0.1204 0.1084 -0.0291 -0.0812 0.1070 -0.0337 0.0663 -0.0206 -0.0756 0.0672 0.0669 0.0596 -0.0812 -0.0528 0.0314 -0.0049 -0.0042 0.0209 -0.0063 0.0324 0.0435 0.0315 0.0121 0.0522 -0.0083 0.0307 0.0329 -0.0047 0.0466 0.0134 0.0426 0.0118 0.0168 0.0448 0.0538 0.0409 0.0133 0.0400 0.0141 <div style="font-family:Lucida Console;font-size:10pt">THE FUND'S PAST PERFORMANCE</div> <div style="font-family:Lucida Console;font-size:10pt">THE FUND'S PAST PERFORMANCE</div> <div style="font-family:Lucida Console;font-size:10pt"><p>For the period covered by the bar chart:</p> <p>THE HIGHEST CALENDAR QUARTERLY RETURN WAS 12.24% (07/01/2009 TO 09/30/2009).</p> <p>THE LOWEST CALENDAR QUARTERLY RETURN WAS -7.48% (07/01/2008 TO 09/30/2008).</p></div> <div style="font-family:Lucida Console;font-size:10pt"><p>For the period covered by the bar chart:</p> <p>THE HIGHEST CALENDAR QUARTERLY RETURN WAS 31.05% (04/01/2003 TO 06/30/2003).</p> <p>THE LOWEST CALENDAR QUARTERLY RETURN WAS -26.86% (07/01/2002 TO 09/30/2002).</p></div> <div style="font-family:Lucida Console;font-size:10pt">The bar chart does not reflect any sales charge you may pay when you buy fund shares. If this amount was reflected, returns would be less than those shown.</div> <div style="font-family:Lucida Console;font-size:10pt">The bar chart does not reflect any sales charge you may pay when you buy fund shares. If this amount was reflected, returns would be less than those shown.</div> <div style="font-family:Lucida Console;font-size:10pt">ANNUAL RETURN CLASS A SHARES (%)</p><p>(Year ended December 31) </p></div> <div style="font-family:Lucida Console;font-size:10pt">ANNUAL RETURN CLASS A SHARES (%)</p><p>(Year ended December 31) </p></div> 0.1224 0.3105 2003-06-30 2009-09-30 -0.2686 -0.0748 2008-09-30 2002-09-30 <div>&lt;div style="display:none;"&gt;~ http://pioneerinvestments.com/role/AnnualTotalReturnsBarChartPioneerGrowthOpportunitiesFund ~&lt;/div&gt;</div> <div>&lt;div style="display:none;"&gt;~ http://pioneerinvestments.com/role/AnnualTotalReturnsBarChartPioneerAMTFreeMunicipalFund ~&lt;/div&gt;</div> 0.0100 0.0050 0.0100 0.0025 0.0000 0.0025 0.0000 0.0100 0.0100 <div style="font-family:Lucida Console;font-size:10pt">You may qualify for sales charge discounts if you or your family invest, or agree to invest in the future, at least $100,000 in Class A shares of the Pioneer funds.</div> <div style="font-family:Lucida Console;font-size:10pt">You may qualify for sales charge discounts if you or your family invest, or agree to invest in the future, at least $50,000 in Class A shares of the Pioneer funds.</div> 100000 50000 <div style="font-family:Lucida Console;font-size:10pt">IF YOU REDEEM YOUR SHARES</div> <div style="font-family:Lucida Console;font-size:10pt">IF YOU REDEEM YOUR SHARES</div> <div style="font-family:Lucida Console;font-size:10pt">EXAMPLE</div> <div style="font-family:Lucida Console;font-size:10pt">EXAMPLE</div> <div style="font-family:Lucida Console;font-size:10pt">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 you invest $10,000 in the fund for the time periods shown and then, except as indicated, redeem all of your shares at the end of those periods. It also assumes that (a) your investment has a 5% return each year and (b) the fund's total annual operating expenses remain the same except for year one (which considers the effect of the expense limitation). Although your actual costs may be higher or lower, based on these assumptions your costs would be:</div> <div style="font-family:Lucida Console;font-size:10pt">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 you invest $10,000 in the fund for the time periods shown and then, except as indicated, redeem all of your shares at the end of those periods. It also assumes that (a) your investment has a 5% return each year and (b) the fund's total annual operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:</div> <div style="font-family:Lucida Console;font-size:10pt">IF YOU DO NOT REDEEM YOUR SHARES</div> <div style="font-family:Lucida Console;font-size:10pt">IF YOU DO NOT REDEEM YOUR SHARES</div> <div>&lt;div style="display:none;"&gt;~ http://pioneerinvestments.com/role/ExpenseExampleNoRedemptionPioneerGrowthOpportunitiesFund ~&lt;/div&gt;</div> <div>&lt;div style="display:none;"&gt;~ http://pioneerinvestments.com/role/ExpenseExampleNoRedemptionPioneerAMTFreeMunicipalFund ~&lt;/div&gt;</div> 696 77 252 56 164 216 175 160 530 952 710 776 181 667 496 546 240 508 876 942 316 1326 1144 1227 417 855 906 2010 1867 1470 712 930 2522 1911 2462 1820 <div>&lt;div style="display:none;"&gt;~ http://pioneerinvestments.com/role/ExpenseExampleTransposedPioneerAMTFreeMunicipalFund ~&lt;/div&gt;</div> <div>&lt;div style="display:none;"&gt;~ http://pioneerinvestments.com/role/ExpenseExamplePioneerGrowthOpportunitiesFund ~&lt;/div&gt;</div> 160 56 316 530 652 264 77 696 575 496 667 846 710 240 508 1076 181 952 906 1144 1227 316 855 1426 417 1042 876 1911 1867 930 2462 2522 712 1820 2010 1470 <div style="font-family:Lucida Console;font-size:10pt">FEES AND EXPENSES OF THE FUND</div> <div style="font-family:Lucida Console;font-size:10pt">FEES AND EXPENSES OF THE FUND</div> <div style="font-family:Lucida Console;font-size:10pt"><p>This table describes the fees and expenses that you may pay if you buy and hold shares of the fund.</p> <p>You may qualify for sales charge discounts if you or your family invest, or agree to invest in the future, at least $50,000 in Class A shares of the Pioneer funds. More information about these and other discounts is available from your investment professional and in the "Sales charges" section of the prospectus beginning on page 29 and the "Sales charges" section of the statement of additional information beginning on page 52.</p></div> <div style="font-family:Lucida Console;font-size:10pt"><p>This table describes the fees and expenses that you may pay if you buy and hold shares of the fund.</p> <p>You may qualify for sales charge discounts if you or your family invest, or agree to invest in the future, at least $100,000 in Class A shares of the Pioneer funds. More information about these and other discounts is available from your investment professional and in the "Sales charges" section of the prospectus beginning on page 36 and the "Sales charges" section of the statement of additional information beginning on page 49.</p></div> 0.0075 0.0174 0.0157 0.0213 0.0161 0.0249 0.0126 0.0087 0.0057 -0.0002 -0.0005 -0.0002 0.0000 <div style="font-family:Lucida Console;font-size:10pt">May 1, 2013</div> <div style="font-family:Lucida Console;font-size:10pt">THE HIGHEST CALENDAR QUARTERLY RETURN</div> <div style="font-family:Lucida Console;font-size:10pt">THE HIGHEST CALENDAR QUARTERLY RETURN</div> <div style="font-family:Lucida Console;font-size:10pt">THE LOWEST CALENDAR QUARTERLY RETURN</div> <div style="font-family:Lucida Console;font-size:10pt">THE LOWEST CALENDAR QUARTERLY RETURN</div> 0.0050 0.0065 0.0065 0.0065 0.0050 0.0065 0.0065 0.0050 0.0050 0.0000 0.0000 0.0100 0.0100 0.0400 0.0000 0.0000 0.0000 0.0400 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0450 0.0575 0.0000 0.0161 0.0172 0.0082 0.0055 <div style="font-family:Lucida Console;font-size:10pt">INVESTMENT OBJECTIVE</div> <div style="font-family:Lucida Console;font-size:10pt">INVESTMENT OBJECTIVE</div> <div style="font-family:Lucida Console;font-size:10pt">Growth of capital.</div> <div style="font-family:Lucida Console;font-size:10pt">As high a level of current interest income exempt from federal income tax as is consistent with the relative stability of capital.</div> <div style="font-family:Lucida Console;font-size:10pt">ANNUAL FUND OPERATING EXPENSES</div><div style="font-family:Lucida Console;font-size:10pt"> (expenses that you pay each year as a percentage of the</div><div style="font-family:Lucida Console;font-size:10pt">value of your investment)</div> <div style="font-family:Lucida Console;font-size:10pt">ANNUAL FUND OPERATING EXPENSES</div><div style="font-family:Lucida Console;font-size:10pt"> (expenses that you pay each year as a </div><div style="font-family:Lucida Console;font-size:10pt">percentage of the value of your investment)</div> 0.0048 0.001 0.0042 0.0024 0.0007 0.0084 0.0011 0.0036 0.0012 <div style="font-family:Lucida Console;font-size:10pt">1-800-225-6292</div> <div style="font-family:Lucida Console;font-size:10pt">1-800-225-6292</div> <div style="font-family:Lucida Console;font-size:10pt"> https://us.pioneerinvestments.com/performance</div> <div style="font-family:Lucida Console;font-size:10pt"> https://us.pioneerinvestments.com/performance</div> <div style="font-family:Lucida Console;font-size:10pt">The bar chart and table indicate the risks and volatility of an investment in the fund by showing how the fund has performed in the past. The bar chart shows changes in the performance of the fund's Class A shares from calendar year to calendar year. The table shows the average annual total returns for each class of the fund over time and compares these returns to the returns of the Barclays Capital Municipal Bond Index, a broad-based measure of market performance that has characteristics relevant to the fund's investment strategies.</div> <div style="font-family:Lucida Console;font-size:10pt">The bar chart and table indicate the risks and volatility of an investment in the fund by showing how the fund has performed in the past. The bar chart shows changes in the performance of the fund's Class A shares from calendar year to calendar year. The table shows the average annual total returns for each class of the fund over time and compares these returns to the returns of the Barclays Capital Municipal Bond Index, a broad-based measure of market performance that has characteristics relevant to the fund's investment strategies.</div> <div style="font-family:Lucida Console;font-size:10pt"><p>The bar chart and table indicate the risks and volatility of an investment in the fund by showing how the fund has performed in the past. The bar chart shows changes in the performance of the fund's Class A shares from calendar year to calendar year. The table shows the average annual total returns for each class of the fund over time and compares these returns to the returns of the Russell 2000 Growth Index, a broad-based measure of market performance that has characteristics relevant to the fund's investment strategies. You can obtain updated performance information by visiting https://us.pioneerinvestments.com/performance or by calling 1-800-225-6292.</p> <p>The fund acquired the assets and liabilities of Safeco Growth Opportunities Fund (the predecessor fund) on December 10, 2004.</p> <p>The performance of Class A, Class B and Class C shares of the fund includes the net asset value performance of the predecessor fund's Class A, Class B and Class C shares prior to the reorganization, which has been restated to reflect differences in any applicable sales charges (but not differences in expenses). If all the expenses of the Pioneer fund were reflected, the performance would be lower. Prior to August 2, 2004, Safeco Asset Management, Inc. served as the predecessor fund's investment adviser.</p> <p>The fund's past performance (before and after taxes) does not necessarily indicate how it will perform in the future.</p> <p>The bar chart does not reflect any sales charge you may pay when you buy fund shares. If this amount was reflected, returns would be less than those shown.</p></div> <div style="font-family:Lucida Console;font-size:10pt"><p>The bar chart and table indicate the risks and volatility of an investment in the fund by showing how the fund has performed in the past. The bar chart shows changes in the performance of the fund's Class A shares from calendar year to calendar year. The table shows the average annual total returns for each class of the fund over time and compares these returns to the returns of the Barclays Capital Municipal Bond Index, a broad-based measure of market performance that has characteristics relevant to the fund's investment strategies. You can obtain updated performance information by visiting https://us.pioneerinvestments.com/performance or by calling 1-800-225-6292.</p> <p>The fund acquired the assets and liabilities of Safeco Municipal Bond Fund (the predecessor fund) on December 10, 2004.</p> <p>The performance of Class A, Class B and Class C shares of the fund includes the net asset value performance of the predecessor fund's Class A, Class B and Class C shares prior to the reorganization, which has been restated to reflect differences in any applicable sales charges (but not differences in expenses). If all the expenses of the Pioneer fund were reflected, the performance would be lower. Prior to August 2, 2004, Safeco Asset Management, Inc. served as the predecessor fund's investment adviser.</p> <p>The fund's past performance (before and after taxes) does not necessarily indicate how it will perform in the future.</p> <p>The bar chart does not reflect any sales charge you may pay when you buy fund shares. If this amount was reflected, returns would be less than those shown.</p></div> <div style="font-family:Lucida Console;font-size:10pt">The fund's past performance (before and after taxes) does not necessarily indicate how it will perform in the future.</div> <div style="font-family:Lucida Console;font-size:10pt">The fund's past performance (before and after taxes) does not necessarily indicate how it will perform in the future.</div> <div style="font-family:Lucida Console;font-size:10pt">AVERAGE ANNUAL TOTAL RETURN (%)</p><p> (for periods ended December 31, 2011)</p></div> <div style="font-family:Lucida Console;font-size:10pt">AVERAGE ANNUAL TOTAL RETURN (%)</p><p> (for periods ended December 31, 2011)</p></div> <div style="font-family:Lucida Console;font-size:10pt"><p>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 the investor's tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold fund shares through tax-deferred arrangements such as 401(k) plans or individual retirement accounts.</p> <p>After-tax returns are shown only for Class A shares. After-tax returns for Class B, Class C, Class R and Class Y shares shares will vary.</p></div> <div style="font-family:Lucida Console;font-size:10pt"><p>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 the investor's tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold fund shares through tax-deferred arrangements such as 401(k) plans or individual retirement accounts.</p> <p>After-tax returns are shown only for Class A shares. After-tax returns for Class B, Class C and Class Y shares will vary.</p></div> <div style="font-family:Lucida Console;font-size:10pt">The after-tax returns shown are not relevant to investors who hold fund shares through tax-deferred arrangements such as 401(k) plans or individual retirement accounts.</div> <div style="font-family:Lucida Console;font-size:10pt">The after-tax returns shown are not relevant to investors who hold fund shares through tax-deferred arrangements such as 401(k) plans or individual retirement accounts.</div> <div style="font-family:Lucida Console;font-size:10pt">After-tax returns are shown only for Class A shares. After-tax returns for Class B, Class C and Class Y shares will vary.</div> <div style="font-family:Lucida Console;font-size:10pt">After-tax returns are shown only for Class A shares. After-tax returns for Class B, Class C and Class Y shares will vary.</div> <div>&lt;div style="display:none;"&gt;~ http://pioneerinvestments.com/role/AverageAnnualTotalReturnsPioneerAMTFreeMunicipalFund ~&lt;/div&gt;</div> <div>&lt;div style="display:none;"&gt;~ http://pioneerinvestments.com/role/AverageAnnualTotalReturnsPioneerGrowthOpportunitiesFund ~&lt;/div&gt;</div> <div style="font-family:Lucida Console;font-size:10pt"><p>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.</div> <div style="font-family:Lucida Console;font-size:10pt"><p>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.</div> <div style="font-family:Lucida Console;font-size:10pt">PORTFOLIO TURNOVER</div> <div style="font-family:Lucida Console;font-size:10pt">PORTFOLIO TURNOVER</div> 0.14 1.12 <div style="font-family:Lucida Console;font-size:10pt">The fund pays transaction costs, such as commissions, when it buys and sells securities (or "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 112% of the average value of its portfolio.</div> <div style="font-family:Lucida Console;font-size:10pt">The fund pays transaction costs, such as commissions, when it buys and sells securities (or "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 14% of the average value of its portfolio.</div> 2012-05-01 <div style="font-family:Lucida Console;font-size:10pt">PRINCIPAL RISKS OF INVESTING IN THE FUND</div> <div style="font-family:Lucida Console;font-size:10pt">PRINCIPAL RISKS OF INVESTING IN THE FUND</div> <div style="font-family:Lucida Console;font-size:10pt">You could lose money on your investment in the fund.</div> <div style="font-family:Lucida Console;font-size:10pt">You could lose money on your investment in the fund.</div> <div style="font-family:Lucida Console;font-size:10pt"><p>You could lose money on your investment in the fund. As with any mutual fund, there is no guarantee that the fund will achieve its objective.</p> <p><b>MARKET RISK.</b> The values of securities held by the fund may go up or down, sometimes rapidly or unpredictably, due to general market conditions, such as real or perceived adverse economic, political, or regulatory conditions, inflation, changes in interest or currency rates or adverse investor sentiment. Adverse market conditions may be prolonged and may not have the same impact on all types of securities. The values of securities may fall due to factors affecting a particular issuer, industry or the securities market as a whole. The stock market may perform poorly relative to other investments (this risk may be greater in the short term). The financial crisis that began in 2008 has caused a significant decline in the value and liquidity of many securities, including securities held by the fund. In response to the crisis, the U.S. and other governments and the Federal Reserve and certain foreign central banks have taken steps to support financial markets. The withdrawal of this support could negatively affect the value and liquidity of certain securities. In addition, legislation recently enacted in the U.S. is changing many aspects of financial regulation. The impact of the legislation on the markets, and the practical implications for market participants, may not be fully known for some time. The fund may experience a substantial or complete loss on any individual security.</p> <p><b>GROWTH STYLE RISK.</b> The fund's investments may not have the growth potential originally expected. Growth stocks may fall out of favor with investors and underperform the overall equity market.</p> <p><b>PORTFOLIO SELECTION RISK.</b> The adviser's judgment about a particular security or issuer, or about the economy or a particular sector, region or market segment, or about an investment strategy, may prove to be incorrect.</p> <p><b>SMALL-SIZE COMPANIES RISK.</b> Compared to large companies, small-size companies, and the market for their equity securities, may be more sensitive to changes in earnings results and investor expectations, have more limited product lines and capital resources, experience sharper swings in market values, have limited liquidity, be harder to value or to sell at the times and prices the adviser thinks appropriate, and offer greater potential for gain and loss.</p> <p><b>DEBT SECURITIES RISK.</b> Factors that could contribute to a decline in the market value of debt securities in the fund include rising interest rates, if the issuer or other obligor of a security held by the fund fails to pay principal and/or interest, otherwise defaults or has its credit rating downgraded or is perceived to be less creditworthy or the credit quality or value of any underlying assets declines. Junk bonds involve greater risk of loss, are subject to greater price volatility and are less liquid, especially during periods of economic uncertainty or change, than higher quality debt securities; they may also be more difficult to value. Junk bonds have a higher risk of default or are already in default and are considered speculative.</p> <p><b>RISKS OF NON-U.S. INVESTMENTS.</b> Investing in non-U.S. issuers may involve unique risks compared to investing in securities of U.S. issuers. These risks are more pronounced for issuers in emerging markets or to the extent that the fund invests significantly in one region or country. These risks may include different financial reporting practices and regulatory standards, less liquid trading markets, extreme price volatility, currency risks, changes in economic, political, regulatory and social conditions, sustained economic downturns, tax burdens, and investment and repatriation restrictions. Non-U.S. issuers may be located in parts of the world that have historically been prone to natural disasters.</p> <p><b>MARKET SEGMENT RISK.</b> To the extent the fund emphasizes, from time to time, investments in a market segment, the fund will be subject to a greater degree to the risks particular to that segment, and may experience greater market fluctuation than a fund without the same focus.</p> <p><b>DERIVATIVES RISK.</b> Using derivatives exposes the fund to additional risks, may increase the volatility of the fund's net asset value and may not provide the result intended. Derivatives may have a leveraging effect on the fund. Changes in a derivative's value may not correlate well with the referenced asset or metric. The fund also may have to sell assets at inopportune times to satisfy its obligations. Derivatives may be difficult to sell, unwind or value, and the counterparty may default on its obligations to the fund. Recent legislation calls for new regulation of the derivatives markets. The extent and impact of the regulation is not yet fully known and may not be for some time. New regulation of derivatives may make them more costly, may limit their availability, or may otherwise adversely affect their value or performance.</p> <p><b>LEVERAGING RISK.</b> The value of your investment may be more volatile and other risks tend to be compounded if the fund borrows or uses derivatives or other investments, such as ETFs, that have embedded leverage. Leverage generally magnifies the effect of any increase or decrease in the value of the fund's underlying assets or creates investment risk with respect to a larger pool of assets than the fund would otherwise have. Engaging in such transactions may cause the fund to liquidate positions when it may not be advantageous to do so to satisfy its obligations or meet segregation requirements.</p> <p><b>PORTFOLIO TURNOVER RISK.</b> If the fund does a lot of trading, it may incur additional operating expenses, which would reduce performance, and could cause shareowners to incur a higher level of taxable income or capital gains.</p> <p><b>EXPENSE RISK.</b> Your actual costs of investing in the fund may be higher than the expenses shown in "Annual fund operating expenses" for a variety of reasons. For example, expense ratios may be higher than those shown if overall net assets decrease. Net assets are more likely to decrease and fund expense ratios are more likely to increase when markets are volatile.</p> <p>Please note that there are many other factors that could adversely affect your investment and that could prevent the fund from achieving its goals.</p> <p>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.</p></div> <div style="font-family:Lucida Console;font-size:10pt"><p>You could lose money on your investment in the fund. As with any mutual fund, there is no guarantee that the fund will achieve its objective.</p> <p><b>MARKET RISK.</b> The values of securities held by the fund may go up or down, sometimes rapidly or unpredictably, due to general market conditions, such as real or perceived adverse economic, political, or regulatory conditions, inflation, changes in interest or currency rates or adverse investor sentiment. Adverse market conditions may be prolonged and may not have the same impact on all types of securities. The values of securities may fall due to factors affecting a particular issuer, industry or the securities market as a whole. The financial crisis that began in 2008 has caused a significant decline in the value and liquidity of many securities, including securities held by the fund. In response to the crisis, the U.S. and other governments and the Federal Reserve and certain foreign central banks have taken steps to support financial markets. The withdrawal of this support could negatively affect the value and liquidity of certain securities. In addition, legislation recently enacted in the U.S. is changing many aspects of financial regulation. The impact of the legislation on the markets, and the practical implications for market participants, may not be fully known for some time. The fund may experience a substantial or complete loss on any individual security.</p> <p><b>INTEREST RATE RISK.</b> Interest rates may go up, causing the value of the fund's investments to decline (this risk generally will be greater for securities with longer maturities).</p> <p><b>CREDIT RISK.</b> If an issuer or guarantor of a security held by the fund or a counterparty to a financial contract with the fund defaults on its obligation to pay principal and/or interest, has its credit rating downgraded or is perceived to be less creditworthy, or the credit quality or value of any underlying assets declines, the value of your investment will decline. Credit risk is broadly gauged by the credit ratings of the securities in which the fund invests. However, ratings are only the opinions of the companies issuing them and are not guarantees as to quality. Junk bonds have a higher risk of default or are already in default and are considered speculative.</p> <p><b>PREPAYMENT OR CALL RISK.</b> Many issuers have a right to prepay their securities. If interest rates fall, an issuer may exercise this right. If this happens, the fund will be forced to reinvest prepayment proceeds at a time when yields on securities available in the market are lower than the yield on the prepaid security. The fund also may lose any premium it paid on the security.</p> <p><b>EXTENSION RISK.</b> During periods of rising interest rates, the average life of certain types of securities may be extended because of slower than expected principal payments. This may lock in a below market interest rate, increase the security's duration (the estimated period until the security is paid in full) and reduce the value of the security.</p> <p><b>LIQUIDITY RISK.</b> Some securities held by the fund may be difficult to sell, or illiquid, particularly during times of market turmoil. Illiquid securities also may be difficult to value. If the fund is forced to sell an illiquid asset to meet redemption requests or other cash needs, the fund may be forced to sell at a loss.</p> <p><b>MUNICIPAL SECURITIES RISK.</b> Municipal issuers may be adversely affected by rising health care costs, increasing unfunded pension liabilities, and by the phasing out of federal programs providing financial support. Unfavorable conditions and developments relating to projects financed with municipal securities can result in lower revenues to issuers of municipal securities. Issuers often depend on revenues from these projects to make principal and interest payments. The value of municipal securities can also be adversely affected by changes in the financial condition of one or more individual municipal issuers or insurers of municipal issuers, regulatory and political developments, tax law changes or other legislative actions, and by uncertainties and public perceptions concerning these and other factors. To the extent the fund invests significantly in a single state or in securities the payments on which are dependent upon a single project or source of revenues, or that relate to a sector or industry, the fund will be more susceptible to associated risks and developments.</p> <p>To the extent that the fund invests in municipal securities whose issuers are located in the state of California, the fund will be more susceptible to economic, political and other developments that may adversely affect California issuers than are funds whose portfolios are more geographically diverse. These developments may include state or local legislation or policy changes, voter-passed initiatives, erosion of the tax base or reduction in revenues of the state or one or more local governments, the effects of terrorist acts or the threat of terrorist acts, the effects of possible natural disasters, or other economic or credit problems affecting the state generally or any individual locality. The major sources of revenues for local government, property taxes and sales taxes, as well as fees based on real estate development, are all adversely affected by the recent economic recession. Unfavorable developments in any economic sector may adversely affect the overall California municipal market. Historically, California's economy has been more volatile than that of the nation as a whole. Although California has a relatively diversified economy, California has concentrations in high technology, trade, entertainment, agriculture, manufacturing, tourism, construction, government and services.</p> <p><b>SYNTHETIC MUNICIPAL SECURITIES RISK.</b> The tax-exempt character of the interest paid on synthetic municipal securities is based on the tax-exempt income stream from the collateral. These securities are subject to the risk that income derived from synthetic municipal securities is deemed to be taxable.</p> <p><b>HIGH YIELD OR "JUNK" BOND RISK.</b> Debt securities that are below investment grade, called "junk bonds," are speculative, have a higher risk of default or are already in default, tend to be less liquid and are more difficult to value than higher grade securities. Junk bonds tend to be volatile and more susceptible to adverse events and negative sentiments.</p> <p><b>PORTFOLIO SELECTION RISK.</b> The adviser's judgment about the quality, relative yield, relative value or market trends affecting a particular sector or region, market segment, security or about interest rates generally may prove to be incorrect.</p> <p><b>RISKS OF COLLATERALIZED DEBT OBLIGATIONS.</b> The risks of an investment in a collateralized debt obligation (CDO) depend largely on the type of the underlying obligations (e.g., an underlying obligation may decline in quality or default) and the tranche of the CDO in which the fund invests (e.g., the fund may invest in a tranche of CDO that is subordinate to other tranches). Investments in CDOs may be characterized by the fund as illiquid securities, which may be difficult to sell at an advantageous time or price.</p> <p><b>RISKS OF SUBORDINATED SECURITIES.</b> A holder of securities that are subordinated or "junior" to more senior securities of an issuer is entitled to payment after holders of more senior securities of the issuer. Subordinated securities are more likely to suffer a credit loss than non-subordinated securities of the same issuer, any loss incurred by the subordinated securities is likely to be proportionately greater, and any recovery of interest or principal may take more time. As a result, even a perceived decline in creditworthiness of the issuer is likely to have a greater impact on them.</p> <p><b>TAXABLE INVESTMENT RISK.</b> Although distributions of interest income from the fund's tax-exempt securities are generally exempt from regular federal income tax, distributions from other sources, including capital gain distributions, and any gains on the sale of your shares are not. In addition, the interest on the fund's municipal securities could become subject to regular federal income tax due to noncompliant conduct by issuers, unfavorable legislation or litigation, or adverse interpretations by regulatory authorities. You should consult a tax adviser about whether an alternative minimum tax applies to you and about state and local taxes on your fund distributions.</p> <p><b>MARKET SEGMENT RISK.</b> To the extent the fund emphasizes, from time to time, investments in a market segment, the fund will be subject to a greater degree to the risks particular to that segment, and may experience greater market fluctuation than a fund without the same focus.</p> <p><b>RISKS OF INVERSE FLOATING RATE OBLIGATIONS.</b> The interest rate on inverse floating rate obligations will generally decrease as short-term interest rates increase, and increase as short-term rates decrease. Due to their leveraged structure, the sensitivity of the market value of an inverse floating rate obligation to changes in interest rates is generally greater than a comparable long-term bond issued by the same issuer and with similar credit quality, redemption and maturity provisions. Inverse floating rate obligations may be volatile and involve leverage risk.</p> <p><b>U.S. GOVERNMENT AGENCY OBLIGATIONS RISK.</b> The fund invests in obligations issued by agencies and instrumentalities of the U.S. government. Government-sponsored entities such as Federal National Mortgage Association (Fannie Mae), Federal Home Loan Mortgage Corporation (Freddie Mac) and the Federal Home Loan Banks (FHLBs), although chartered or sponsored by Congress, are not funded by congressional appropriations and the debt and mortgage-backed securities issued by them are neither guaranteed nor issued by the U.S. government. Although the U.S. government has provided financial support to Fannie Mae and Freddie Mac in the past, there can be no assurance that it will support these or other government-sponsored entities in the future. Such debt and mortgage-backed securities are subject to the risk of default on the payment of interest and/or principal, similar to debt of private issuers.</p> <p><b>DERIVATIVES RISK.</b> Using derivatives exposes the fund to additional risks, may increase the volatility of the fund's net asset value and may not provide the result intended. Derivatives may have a leveraging effect on the fund. Changes in a derivative's value may not correlate well with the referenced asset or metric. The fund also may have to sell assets at inopportune times to satisfy its obligations. Derivatives may be difficult to sell, unwind or value, and the counterparty may default on its obligations to the fund. Recent legislation calls for new regulation of the derivatives markets. The extent and impact of the regulation is not yet fully known and may not be for some time. New regulation of derivatives may make them more costly, may limit their availability, or may otherwise adversely affect their value or performance.</p> <p><b>REPURCHASE AGREEMENT RISK.</b> In the event that the other party to a repurchase agreement defaults on its obligations, the fund may encounter delay and incur costs before being able to sell the security. Such a delay may involve loss of interest or a decline in price of the security. In addition, if the fund is characterized by a court as an unsecured creditor, it would be at risk of losing some or all of the principal and interest involved in the transaction.</p> <p><b>LEVERAGING RISK.</b> The value of your investment may be more volatile and other risks tend to be compounded if the fund borrows or uses derivatives or other investments, such as ETFs, that have embedded leverage. Leverage generally magnifies the effect of any increase or decrease in the value of the fund's underlying assets or creates investment risk with respect to a larger pool of assets than the fund would otherwise have. Engaging in such transactions may cause the fund to liquidate positions when it may not be advantageous to do so to satisfy its obligations or meet segregation requirements.</p> <p><b>EXPENSE RISK.</b> Your actual costs of investing in the fund may be higher than the expenses shown in "Annual fund operating expenses" for a variety of reasons. For example, expense ratios may be higher than those shown if overall net assets decrease. Net assets are more likely to decrease and fund expense ratios are more likely to increase when markets are volatile.</p> <p>Please note that there are many other factors that could adversely affect your investment and that could prevent the fund from achieving its goals.</p> <p>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.</p></div> <div style="font-family:Lucida Console;font-size:10pt">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.</div> <div style="font-family:Lucida Console;font-size:10pt">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.</div> <div style="font-family:Lucida Console;font-size:10pt">PIONEER AMT-FREE MUNICIPAL FUND</div> <div style="font-family:Lucida Console;font-size:10pt">PIONEER GROWTH OPPORTUNITIES FUND</div> <div style="font-family:Lucida Console;font-size:10pt">SHAREOWNER FEES</div><div style="font-family:Lucida Console;font-size:10pt"> (fees paid directly from your investment)</div> <div style="font-family:Lucida Console;font-size:10pt">SHAREOWNER FEES</div><div style="font-family:Lucida Console;font-size:10pt"> (fees paid directly from your investment)</div> <div>&lt;div style="display:none;"&gt;~ http://pioneerinvestments.com/role/ShareholderFeesPioneerAMTFreeMunicipalFund ~&lt;/div&gt;</div> <div>&lt;div style="display:none;"&gt;~ http://pioneerinvestments.com/role/ShareholderFeesPioneerGrowthOpportunitiesFund ~&lt;/div&gt;</div> <div style="font-family:Lucida Console;font-size:10pt">PRINCIPAL INVESTMENT STRATEGIES</div> <div style="font-family:Lucida Console;font-size:10pt">PRINCIPAL INVESTMENT STRATEGIES</div> <div style="font-family:Lucida Console;font-size:10pt"><p>Normally, the fund invests at least 80% of its net assets (plus the amount of borrowings, if any, for investment purposes) in investment grade municipal bonds with a maturity of more than one year, the interest on which is exempt from regular federal income tax. For purposes of satisfying the 80% requirement, the fund also may invest in derivative instruments that have economic characteristics similar to such municipal securities. The fund normally will not invest in securities the interest on which is a tax preference item for purposes of the federal alternative minimum tax (AMT).</p> <p>The fund's investments include bonds, notes and other debt instruments issued by or on behalf of states, counties, municipalities, territories and possessions of the United States and the District of Columbia and their authorities, political subdivisions, agencies or instrumentalities.</p> <p>The fund may invest up to 10% of its net assets in debt securities rated below investment grade (known as "junk bonds"). The fund's investments in debt securities rated below investment grade may include debt securities rated "D" or better, or comparable unrated securities.</p> <p>The fund may invest in municipal securities of any maturity, although under normal circumstances it is anticipated that the fund will generally invest in longer-term investments.</p> <p>The fund may invest 25% or more of its assets in issuers in any one or more states or securities the payments on which are derived from gas, electric, telephone, sewer, water, healthcare, education and transportation segments of the municipal bond market.</p> <p>The fund's investments may have fixed or variable principal payments and all types of interest rate payment and reset terms, including fixed rate, inverse floating rate, floating rate, zero coupon, contingent, deferred and payment in kind and auction rate features. The fund's investments may include instruments that allow for balloon payments or negative amortization payments.</p> <p>The fund normally will limit its investment in municipal securities whose issuers are located in the same state to less than 25% of the fund's total assets.</p> <p>The fund may use derivatives, such as synthetic municipal securities, inverse floating rate obligations, for a variety of purposes, including: as a hedge against adverse changes in the market price of securities, interest rates or currency exchange rates; as a substitute for purchasing or selling securities; and to increase the fund's return as a non-hedging strategy that may be considered speculative. The fund may invest up to 10% of its net assets in inverse floating rate obligations. The fund also may invest in subordinated securities and collateralized debt obligations, and may hold cash or other short-term investments.</p> <p>The fund may invest up to 20% of its net assets in taxable investments, including securities of other investment companies, commercial paper, U.S. government securities, U.S. or foreign bank instruments and repurchase agreements.</p> <p>The fund's investment adviser, considers both broad economic factors and issuer specific factors in selecting investments to buy and sell. In assessing the appropriate maturity and rating weighting of the fund's portfolio, the adviser considers a variety of factors that are expected to influence economic activity and interest rates. The adviser selects individual securities based upon such factors as a security's yield, liquidity and rating, an assessment of credit quality and issuer diversification.</p></div> <div style="font-family:Lucida Console;font-size:10pt"><p>The fund invests primarily in equity securities of companies that the fund's investment adviser considers to be reasonably priced or undervalued, with above average growth potential. For purposes of the fund's investment policies, equity securities include common stocks, debt convertible to equity securities and other equity instruments, such as exchange-traded funds (ETFs) that invest primarily in equity securities, depositary receipts, equity interests in real estate investment trusts (REITs), warrants, rights and preferred stocks.</p> <p>The fund may invest in securities of any market capitalization, although the fund may invest a significant portion of its assets in equity securities of small companies. The fund defines small companies as those within the market capitalization range of the Russell 2000 Growth Index (approximately $2.7 million to $3.6 billion as of March 31, 2012). The size of the companies in the index changes constantly with market conditions and the composition of the index. The fund may continue to hold a security if its market capitalization changes after investment.</p> <p>The fund may invest up to 20% of its total assets in debt securities of U.S. issuers. Generally the fund acquires debt securities that are investment grade, but the fund may invest up to 5% of its net assets in below investment grade debt securities (known as "junk bonds"), and below investment grade convertible debt securities.</p> <p>The fund may invest up to 20% of its total assets in securities of non-U.S. issuers, including up to 5% of its total assets in securities of emerging markets issuers.</p> <p>The fund may use derivatives, such as options and futures, for a variety of purposes, including: as a hedge against adverse changes in the market prices of securities, interest rates or currency exchange rates; as a substitute for purchasing or selling securities; and to increase the fund's return as a non-hedging strategy that may be considered speculative. The fund also may hold cash or other short-term investments.</p> <p>The fund uses a "growth at a reasonable price" style of management and seeks to invest in securities of issuers with above average potential for earnings and revenue growth that are also trading at attractive market valuations. To select stocks, the fund's investment adviser employs fundamental research and an evaluation of the issuer based on its financial statements and operations, utilizing a bottom-up analytic style which focuses on specific securities rather than industries. The adviser may also use quantitative analysis. The adviser focuses on the quality and price of individual issuers and securities.</p> <p>The adviser generally sells a portfolio security when it believes that the issuer no longer offers the potential for growth at a reasonable price or if any of the factors used to select an investment have deteriorated. The adviser makes that determination based upon the same criteria it uses to select portfolio securities.</p></div> The fund's investment adviser has contractually agreed to limit ordinary operating expenses (ordinary operating expenses means all fund expenses other than extraordinary expenses, such as litigation, taxes and brokerage commissions) to the extent required to reduce fund expenses to 0.82%, 1.72% and 0.55% of the average daily net assets attributable to Class A, Class B and Class Y shares, respectively. These expense limitations are in effect through May 1, 2013. There can be no assurance that the adviser will extend the expense limitation beyond such time. While in effect, the arrangement may be terminated for a class only by agreement of the adviser and the Board of Trustees.