Pioneer Emerging
                        Markets Fund

--------------------------------------------------------------------------------
                        Semiannual Report | May 31, 2017
--------------------------------------------------------------------------------

                        Ticker Symbols:
                        Class A     PEMFX
                        Class C     PCEFX
                        Class R     PEMRX
                        Class Y     PYEFX

                       [LOGO]   Amundi Pioneer
                                ==============
                              ASSET MANAGEMENT

                        visit us: www.amundipioneer.com



Table of Contents


                                                                          
President's Letter                                                             2

Portfolio Management Discussion                                                4

Portfolio Summary                                                              9

Prices and Distributions                                                      10

Performance Update                                                            11

Comparing Ongoing Fund Expenses                                               15

Schedule of Investments                                                       17

Financial Statements                                                          23

Notes to Financial Statements                                                 31

Approval of New and Interim Management Agreements                             47

Trustees, Officers and Service Providers                                      60


                   Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17 1


President's Letter

U.S. markets have continued to generate positive returns during the first
several months of 2017, with so-called "risk" assets, such as equities and
credit-sensitive bonds, posting solid gains. U.S. equities, as measured by the
Standard & Poor's 500 Index, returned slightly more than 6% in the first
calendar quarter of the year and more than 3% for the second quarter. Meanwhile,
high-yield securities have dominated bond market performance thus far in 2017.

The post-election market momentum we witnessed in the U.S. during the final
weeks of the fourth quarter of 2016 slowed only when oil prices slumped in
March, due to both higher-than-expected inventories and concerns over whether
OPEC (Organization of Petroleum Exporting Countries) would continue its supply
cuts. Not even the Federal Reserve System's (the Fed's) two rate hikes since
March, nor Britain's trigger of Article 50 to begin the "Brexit" process caused
any dramatic sell-off of risk assets. In fact, we are encouraged by the more
hawkish stance of the Fed with regard to interest rates, in light of our view
that current U.S. bond yields do not fairly reflect the prospective levels of
economic activity and inflation. We expect the Fed to continue to tighten
monetary policy, with at least one more rate hike likely to occur before the end
of 2017.

While U.S. gross domestic product (GDP) did slow in the first quarter, ending up
at 1.4% after revisions, the expectation is for GDP growth to pick-up in the
second quarter, with a solid consumer leading the way. It is our view that the
U.S. economy may lead all developed nations in 2017, with GDP growth in excess
of 2% for the full year, even if proposed tax and regulatory reforms are not
passed into law in the near future. We also believe solid domestic employment
figures should continue to support consumption and the housing market, and that
stronger corporate profits and increased government spending may contribute to
economic growth in 2018 and beyond. In addition, as we monitor global Purchasing
Manager Indices (PMIs), we note that their numbers are increasing, which
suggests that growth in global economies is also improving. (PMIs are used to
measure the economic health of the manufacturing sector.)

There are, as always, some risks to our outlook. First, the market already has
priced in a good deal of the Trump economic reform platform, and that could lead
to near-term disappointment if Congressional follow-through does not happen this
year. The future of the Affordable Care Act (ACA) is another potential concern,
as Congressional leaders have, thus far, failed to generate

2 Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17


enough support to get new health care legislation approved by both houses.
However, if a bill is eventually passed that either eliminates or significantly
alters the ACA, the new law will undoubtedly have an effect on the health care
sector, one of the largest segments of the U.S. economy. Geopolitical risks, of
course, remain a potential headwind, given ongoing strife in the Middle East and
renewed tensions on the Korean Peninsula.

While our current outlook is generally optimistic, conditions can and often do
change, and while passive investment strategies may have a place in one's
overall portfolio, it is our view that all investment decisions are active
choices.

Throughout our history, we have believed in the importance of active management.
The active decisions to invest in equities or fixed-income securities are made
by a team of experienced investment professionals focusing on identifying value
across global markets using proprietary research, careful risk management, and a
long-term perspective. We believe our shareowners can benefit from the
experience and tenure of our investment teams as well as the insights generated
from our extensive research process.

As always, and particularly during times of market uncertainty, we encourage you
to work with your financial advisor to develop an overall investment plan that
addresses both your short- and long-term goals, and to implement such a plan in
a disciplined manner.

We greatly appreciate the trust you have placed in us and look forward to
continuing to serve you in the future.

Sincerely,

/s/ Lisa M. Jones

Lisa M. Jones
Head of the Americas, President and CEO of US
Amundi Pioneer Asset Management USA, Inc.
May 31, 2017

Any information in this shareowner report regarding market or economic trends or
the factors influencing the Fund's historical or future performance are
statements of opinion as of the date of this report. Past performance is no
guarantee of future results.

                   Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17 3


Portfolio Management Discussion | 5/31/17

Important Note: On July 3, 2017, Amundi acquired Pioneer Investments, a group of
asset management companies located throughout the world. Amundi, one of the
world's largest asset managers, is headquartered in Paris, France. As a result
of the transaction, Pioneer Investment Management, Inc., the Fund's investment
adviser, became an indirect wholly owned subsidiary of Amundi and Amundi's
wholly owned subsidiary, Amundi USA, Inc. Prior to July 3, 2017, Pioneer
Investments was owned by Pioneer Global Asset Management S.p.A., a wholly owned
subsidiary of UniCredit S.p.A.

In connection with the transaction, the names of the Fund's investment adviser
and principal underwriter changed. Effective July 3, 2017, the name of Pioneer
Investment Management, Inc. changed to Amundi Pioneer Asset Management, Inc. and
the name of Pioneer Funds Distributor, Inc. changed to Amundi Pioneer
Distributor, Inc.

This transaction does not impact your existing relationship with Pioneer
Investments, your advisor, or the methods you use to communicate with us, as the
investor contact telephone numbers and services you expect will remain the same.
We are excited, however, to be launching a new website representing the combined
company. Come visit us at: www.amundipioneer.com

In the following interview, Mauro Ratto, Marco Mencini, and Andrea Salvatori,
portfolio managers of Pioneer Emerging Markets Fund*, discuss the investment
environment and the Fund's performance during the six-month period ended May 31,
2017. Mr. Ratto, Head of Emerging Markets Investment Management at Amundi
Pioneer Asset Management, Inc., (Amundi Pioneer), Mr. Mencini, Head of Equities,
Emerging Markets, and a senior vice president at Amundi Pioneer, and Mr.
Salvatori, Head of Global Emerging Markets & Latin American Equities, a senior
vice president and a senior portfolio manager at Amundi Pioneer, are responsible
for the day-to-day management of the Fund.

Q    How did the Fund perform during the six-month period ended May 31, 2017?

A    Pioneer Emerging Markets Fund's Class A shares returned 23.43% at net asset
     value during the six-month period ended May 31, 2017, while the Fund's
     benchmark, the Morgan Stanley Capital International (MSCI) Emerging Markets
     ND Index (the MSCI Index)1, returned 17.51%. During

*    In July 2017, the Board of Trustees of the Pioneer Funds approved the
     reorganization of Pioneer Emerging Markets Fund into Pioneer Global Equity
     Fund. The combined fund will be renamed Pioneer Global Equity Fund. The
     reorganization is expected to be completed during the fourth calendar
     quarter of 2017. Shareholders will receive further information regarding
     the reorganization in the coming weeks.

1    The MSCI information may only be used for your internal use, may not be
     reproduced or re-disseminated in any form and may not be used as a basis
     for or a component of any financial instruments or products or indices.
     None of the MSCI information is intended to constitute investment advice or
     a recommendation to make (or refrain from making) any kind of investment
     decision and may not be relied on as such. Historical data and analysis
     should not be taken as an indication or guarantee of any future performance
     analysis, forecast or prediction. The MSCI information is provided on an
     "as is" basis and the user of this information assumes the entire risk of
     any use made of this information. MSCI, each of its affiliates and each
     other person involved in or related to compiling, computing or creating any
     MSCI information (collectively, the "MSCI Parties") expressly disclaims all
     warranties (including, without limitation, any warranties of originality,
     accuracy, completeness, timeliness, non-infringement, merchantability and
     fitness for a particular purpose) with respect to this information. Without
     limiting any of the foregoing, in no event shall any MSCI Party have any
     liability for any direct, indirect, special, incidental, punitive,
     consequential (including, without limitation, lost profits) or any other
     damages.

4 Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17


     the same period, the average return of the 856 mutual funds in Lipper's
     Emerging Markets Funds category was 16.81%, and the average return of the
     843 mutual funds in Morningstar's Diversified Emerging Markets Funds
     category was 17.05%.

Q    Could you please review the performance of emerging markets stocks during
     the six-month period ended May 31, 2017?

A    The robust performance for emerging markets equities during the period
     reflected the highly favorable investment backdrop that characterized the
     six months. A steady expansion of global economic growth, increased
     investor optimism following the U.S. elections in November 2016, stable
     commodity prices, and U.S. dollar weakness combined to create a very
     positive environment for the higher-risk segments of world equity markets.
     With China, India, and other key nations demonstrating signs of stronger
     economic growth, investors appeared comfortable moving into emerging
     markets stocks in order to capitalize on their attractive valuations.
     Notably, rising demand from broad-based global investors - as opposed to
     those who invest solely in the emerging markets - represented a renewed
     source of support that has been largely missing in recent years.

Q    Which of your investment decisions had the greatest effect on the Fund's
     performance during the six-month period ended May 31, 2017?

A    In managing the Fund, we use a bottom-up approach that seeks to identify
     the most compelling stock ideas anywhere within the emerging markets
     investment universe. Rather than constructing the portfolio in a manner
     that strives to mimic the composition of the MSCI Index benchmark, we focus
     on finding what we believe to be undervalued companies with unappreciated
     catalysts for improved performance. As part of the process, we try to find
     companies with effective corporate governance as well as a strong
     shareholder focus, traits that are often demonstrated through above-
     average dividend* payments and stock buybacks. We believe this approach is
     more prudent than buying stocks of poorly managed or overvalued companies
     simply because they might be components of the Fund's benchmark.

     Our investment strategy served the Fund well over the past six months, as
     many of the portfolio's positions in companies with either a small
     representation or a zero weighting in the MSCI Index produced market-
     beating gains. Although our investment approach for the Fund is designed
     for longer-term outperformance rather than benchmark-relative strength in
     specific six-month intervals, we think the Fund's strong showing during the
     semiannual period helps illustrate the potential value of our investment
     style.

*    Dividends are not guaranteed.

                   Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17 5


Q    Which aspects of the Fund's positioning had the largest impact on
     benchmark-relative returns during the six-month period ended May 31, 2017?

A    Consistent with our bottom-up methodology, stock selection was the primary
     driver of the Fund's benchmark-relative outperformance during the six-month
     period. At the country level, the Fund benefited from positive stock
     selection in South Africa, India, and Brazil. With regard to sectors, the
     Fund posted its best benchmark-relative results in financials, materials,
     and telecommunication services. Conversely, the Fund lost some ground
     against the benchmark from stock selection in the energy and information
     technology sectors, as well as in Mexico.

     Among individual portfolio positions, shares of MMG, an Australia-listed
     company that primarily operates in China, was the top contributor to the
     Fund's benchmark-relative performance thanks to improving sales volumes and
     a recovery in the price of copper. The Nigerian stock United Bank for
     Africa also made a significant contribution to the Fund's benchmark-
     relative returns during the period. We originally purchased the stock as a
     play on the changing dynamics of the Nigerian economy, and the shares have
     rallied over the past six months due to the government's successful
     monetary policy reforms, including a currency devaluation, which have
     energized Nigerian economic growth. The Fund's positions in Brazilian
     companies Tim Participacoes and Tupy, which operate in the
     telecommunications and automotive sectors, respectively, also were positive
     contributors to benchmark-relative returns, as were portfolio positions in
     Asian technology stocks Alibaba Group (China), Samsung Electronics (Korea),
     and Hon Hai Precision Industry (Taiwan).

     Finally, the Fund's position in Naspers, a South African media company,
     helps illustrate our bottom-up security selection process. A key reason for
     our purchase of the stock was that one of Naspers' primary holdings is its
     stake in the Chinese internet company Tencent Holding. Naspers' holding in
     Tencent provided a way for the Fund to gain access to one of China's
     leading media companies at a lower cost than it would have incurred through
     a direct purchase of Tencent's stock. Further, we believed Naspers' stock
     price did not reflect the appropriate value of the company's core South
     African business. The market eventually came to appreciate these factors
     during the past six months, leading to a narrowing of the stock's valuation
     discount and a strong benefit for the Fund's benchmark-relative
     performance.

     On the negative side, the portfolio holding that detracted the most from
     the Fund's benchmark-relative returns during the period was ChinaCache, a
     provider of Internet content and application delivery services (in China)
     that posted weaker-than-expected results. Also in China, the Fund's
     position in Goodbaby International, which manufactures strollers, car
     seats, and other child safety products, and which made a large, positive
     contribution to performance in 2016, has given back some ground in recent
     months due to concerns about the company's ability to maintain its current
     market share. We continue to hold a positive view on Goodbaby, however,

6 Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17


     and so the shares remain in the Fund's portfolio. Finally, KenolKobil
     Limited, a downstream oil company located in Kenya, also detracted from the
     Fund's benchmark-relative returns during the period, even though it
     demonstrated an improvement in both revenues and profit margins. In our
     view, the company's share price has been affected by investors' concerns
     about its businesses outside of Kenya.

Q    Did you invest in any derivatives while managing the Fund during the
     six-month period ended May 31, 2017? If so, did the derivative positions
     have any effect on the Fund's performance?

A    We used derivatives in the form of forward foreign currency contracts in an
     attempt to help manage the Fund's risk and volatility profiles during the
     period. In addition, we used index futures as a way to gain portfolio
     exposure to specific countries quickly and efficiently, when value
     opportunities presented themselves. The Fund's use of derivatives was a net
     detractor from benchmark-relative performance during the period, but it is
     important to keep in mind that the use of derivatives represents only a
     part of our overall investment approach, rather than a stand-alone
     strategy.

Q    How would you characterize the Fund's overall positioning as of May 31,
     2017?

A    During the period, we continued to seek out what we felt were the best
     investment ideas in the financials, industrials, and consumer discretionary
     sectors. At the same time, the Fund held below-market weightings in more
     capital-intensive - and therefore more interest-rate sensitive - sectors
     such as real estate, materials, and utilities. The portfolio's allocations
     reflect a granular investment process that places an emphasis on individual
     stock picks over broader sector positioning.

     At the country level, we currently favor Brazil, China, and Nigeria.
     Although Brazilian equities weakened late in the period due to revived
     concerns about the impact of corruption on the governmental reform process,
     we retain a constructive view on the country based on the potential for a
     continued economic recovery. We were also pleased to see Chinese economic
     figures surprising to the upside, which supports the Fund's sizable
     position in that country. In addition, it is our view that the Fund's
     out-of-benchmark positioning in the Nigerian banking sector could
     potentially benefit from both compelling valuations and supportive local
     dynamics in the wake of last year's currency devaluation.

     Conversely, we have maintained the Fund's underweights in Taiwan and Korea,
     and we have taken a cautious stance toward Russia, given that many of that
     nation's companies appear less appealing than their regional peers.

Q    What are your broader thoughts on emerging markets equities heading into
     the second half of 2017?

A    Emerging markets stocks continue to trade at attractive valuations relative
     to their developed-market peers. Whereas valuations in the latter category
     were at the top end of their historical ranges at the close of the
     six-month period,

                   Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17 7


     valuations in the emerging markets were near their long-term averages.
     While we believe this helps provide a firm foundation for performance, we
     also think that stock selection remains a crucial factor. There is a
     significant dispersion in the quality of corporate governance between the
     most well-managed firms and those that still need to adopt more stringent
     business practices. Additionally, the breadth of the emerging markets
     equities asset class means that individual companies will be affected in
     much different ways by shifts in commodity prices, currency movements, and
     changes in the relative economic growth trends among regions.

     With this as background, we continue to believe a bottom-up approach
     remains essential to addressing the full range of both the opportunities
     and risks that come with investing in the emerging markets.

Please refer to the Schedule of Investments on pages 17-22 for a full listing of
Fund securities.

All investments are subject to risk, including the possible loss of principal.
In the past several years, financial markets have experienced increased
volatility, depressed valuations, decreased liquidity and heightened
uncertainty. These conditions may continue, recur, worsen or spread.

Investing in foreign and/or emerging markets securities involves risks relating
to interest rates, currency exchange rates, economic, and political conditions.

To the extent the Fund invests in issuers located within specific countries or
regions, the Fund may be particularly affected by adverse markets, rates, and
events, which may occur in those countries and regions.

At times, the Fund's investments may represent industries or industry sectors
that are interrelated or have common risks, making it more susceptible to any
economic, political, or regulatory developments or other risks affecting those
industries and sectors.

These risks may increase share price volatility.

Before investing, consider the product's investment objectives, risks, charges
and expenses. Contact your advisor or Amundi Pioneer Asset Management, Inc., for
a prospectus or summary prospectus containing this information. Read it
carefully.

Any information in this shareholder report regarding market or economic trends
or the factors influencing the Fund's historical or future performance are
statements of opinion as of the date of this report. Past performance is no
guarantee of future results.

8 Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17


Portfolio Summary | 5/31/17

Sector Distribution
--------------------------------------------------------------------------------
(As a percentage of long-term holdings)

[THE FOLLOWING DATA WAS REPRESENTED AS A PIE CHART IN THE PRINTED MATERIAL]



                                                                       
Information Technology                                                    33.4%
Financials                                                                25.2%
Consumer Discretionary                                                     9.4%
Industrials                                                                8.9%
Consumer Staples                                                           8.7%
Energy                                                                     7.8%
Telecommunication Services                                                 4.4%
Materials                                                                  2.2%
Real Estate                                                                0.0%*
Health Care                                                                0.0%*


* Amount rounds to less than 0.1%.

Geographical Distribution
--------------------------------------------------------------------------------
(As a percentage of long-term holdings)

[THE FOLLOWING DATA WAS REPRESENTED AS A BAR CHART IN THE PRINTED MATERIAL]



                                                                        
China                                                                      23.1%
Brazil                                                                     12.0%
South Korea                                                                11.6%
Taiwan                                                                      8.6%
Russia                                                                      6.3%
Nigeria                                                                     6.3%
France                                                                      5.2%
South Africa                                                                5.2%
Philippines                                                                 4.8%
Greece                                                                      4.6%
India                                                                       4.5%
Belgium                                                                     4.1%
Egypt                                                                       2.2%
Kenya                                                                       1.5%


10 Largest Holdings
--------------------------------------------------------------------------------
(As a percentage of long-term holdings)*



                                                                        
 1.   United Bank for Africa Plc                                           6.31%
--------------------------------------------------------------------------------
 2.   TMK PJSC                                                             5.68
--------------------------------------------------------------------------------
 3.   Wonik IPS Co., Ltd.                                                  5.26
--------------------------------------------------------------------------------
 4.   Naspers, Ltd.                                                        5.19
--------------------------------------------------------------------------------
 5.   S.O.I.T.E.C. SA                                                      5.14
--------------------------------------------------------------------------------
 6.   Tupy SA                                                              5.11
--------------------------------------------------------------------------------
 7.   Philippine National Bank                                             4.83
--------------------------------------------------------------------------------
 8.   Marfrig Global Foods SA                                              4.61
--------------------------------------------------------------------------------
 9.   Alibaba Group Holding, Ltd.                                          4.58
--------------------------------------------------------------------------------
10.   HDFC Bank, Ltd.                                                      4.54
--------------------------------------------------------------------------------


*    This list excludes temporary cash investments and derivative instruments.
     The portfolio is actively managed, and current holdings may be different.
     The holdings listed should not be considered recommendations to buy or sell
     any securities listed.

                   Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17 9


Prices and Distributions | 5/31/17

Net Asset Value per Share
--------------------------------------------------------------------------------



--------------------------------------------------------------------------------
       Class                     5/31/17                         11/30/16
--------------------------------------------------------------------------------
                                                            
        A                         $20.07                          $16.25
--------------------------------------------------------------------------------
        C                         $16.34                          $13.30
--------------------------------------------------------------------------------
        R                         $19.12                          $15.51
--------------------------------------------------------------------------------
        Y                         $22.20                          $17.97
--------------------------------------------------------------------------------


Distributions per Share: 12/1/16-5/31/17
--------------------------------------------------------------------------------



--------------------------------------------------------------------------------
                          Net
                      Investment         Short-Term          Long-Term
       Class            Income          Capital Gains       Capital Gains
--------------------------------------------------------------------------------
                                                       
        A                $ --               $ --                $ --
--------------------------------------------------------------------------------
        C                $ --               $ --                $ --
--------------------------------------------------------------------------------
        R                $ --               $ --                $ --
--------------------------------------------------------------------------------
        Y                $ --               $ --                $ --
--------------------------------------------------------------------------------


The MSCI Emerging Markets ND Index is an unmanaged index that measures the
performance of emerging market stocks. Index returns are calculated monthly,
assume reinvestment of dividends and, unlike Fund returns, do not reflect any
sales charges, fees or expenses. It is not possible to invest directly in an
index.

The index defined here pertains to the "Value of $10,000 Investment" and "Value
of $5 Million Investment" charts on pages 11-14.

10 Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17


Performance Update | 5/31/17                                      Class A Shares

Investment Returns
--------------------------------------------------------------------------------
The mountain chart on the right shows the change in value of a $10,000
investment made in Class A shares of Pioneer Emerging Markets Fund at public
offering price during the periods shown, compared to that of the Morgan Stanley
Capital International (MSCI) Emerging Markets ND Index.



Average Annual Total Returns
(As of May 31, 2017)
--------------------------------------------------------------------------------
                       Net               Public             MSCI
                       Asset             Offering           Emerging
                       Value             Price              Markets
Period                 (NAV)             (POP)              ND Index
--------------------------------------------------------------------------------
                                                   
10 Years               -2.16%            -2.74%              2.28%
5 Years                 1.69              0.49               4.54
1 Year                 23.58             16.48              27.41
--------------------------------------------------------------------------------


Expense Ratio
(Per prospectus dated April 1, 2017)
--------------------------------------------------------------------------------
                       Gross             Net
--------------------------------------------------------------------------------
                                   
                       2.28%             1.95%
--------------------------------------------------------------------------------


[THE FOLLOWING DATA WAS REPRESENTED AS A MOUNTAIN CHART IN THE PRINTED MATERIAL]

Value of $10,000 Investment



            Pioneer Emerging Markets Fund       MSCI Emerging Markets ND Index
                                          
5/07        $ 9,425                             $10,000
5/08        $11,216                             $12,167
5/09        $ 6,467                             $ 7,987
5/10        $ 7,463                             $ 9,675
5/11        $ 9,519                             $12,595
5/12        $ 6,966                             $10,035
5/13        $ 7,483                             $11,450
5/14        $ 8,067                             $11,939
5/15        $ 7,201                             $11,938
5/16        $ 6,128                             $ 9,833
5/17        $ 7,574                             $12,528


Call 1-800-225-6292 or visit www.amundipioneer.com for the most recent month-end
performance results. Current performance may be lower or higher than the
performance data quoted.

The performance data quoted represents past performance, which is no guarantee
of future results. Investment return and principal value will fluctuate, and
shares, when redeemed, may be worth more or less than their original cost.

NAV results represent the percent change in net asset value per share. Returns
would have been lower had sales charges been reflected. POP returns reflect
deduction of maximum 5.75% sales charge. All results are historical and assume
the reinvestment of dividends and capital gains. Other share classes are
available for which performance and expenses will differ.

Performance results reflect any applicable expense waivers in effect during the
periods shown. Without such waivers Fund performance would be lower. Waivers may
not be in effect for all funds. Certain fee waivers are contractual through a
specified period. Otherwise, fee waivers can be rescinded at any time. See the
prospectus and financial statements for more information.

The net expense ratio reflects the contractual expense limitation currently in
effect through April 1, 2018, for Class A shares. There can be no assurance that
Amundi Pioneer will extend the expense limitation beyond such time. Please see
the prospectus and financial statements for more information.

The performance table and graph do not reflect the deduction of fees and taxes
that a shareowner would pay on Fund distributions or the redemption of Fund
shares.

Please refer to the financial highlights for a more current expense ratio.

                  Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17 11


Performance Update | 5/31/17                                      Class C Shares

Investment Returns
--------------------------------------------------------------------------------
The mountain chart on the right shows the change in value of a $10,000
investment made in Class C shares of Pioneer Emerging Markets Fund during the
periods shown, compared to that of the Morgan Stanley Capital International
(MSCI) Emerging Markets ND Index.



Average Annual Total Returns
(As of May 31, 2017)
--------------------------------------------------------------------------------
                                                            MSCI
                                                            Emerging
                       If                If                 Markets
Period                 Held              Redeemed           ND Index
--------------------------------------------------------------------------------
                                                   
10 Years               -2.98%            -2.98%              2.28%
5 Years                 0.81              0.81               4.54
1 Year                 22.49             22.49              27.41
--------------------------------------------------------------------------------


Expense Ratio
(Per prospectus dated April 1, 2017)
--------------------------------------------------------------------------------
                       Gross             Net
--------------------------------------------------------------------------------
                                   
                       3.06%             2.85%
--------------------------------------------------------------------------------


[THE FOLLOWING DATA WAS REPRESENTED AS A MOUNTAIN CHART IN THE PRINTED MATERIAL]

Value of $10,000 Investment



             Pioneer Emerging Markets Fund        MSCI Emerging Markets ND Index
                                            
5/07         $10,000                              $10,000
5/08         $11,809                              $12,167
5/09         $ 6,751                              $ 7,987
5/10         $ 7,727                              $ 9,675
5/11         $ 9,775                              $12,595
5/12         $ 7,095                              $10,035
5/13         $ 7,562                              $11,450
5/14         $ 8,084                              $11,939
5/15         $ 7,154                              $11,938
5/16         $ 6,032                              $ 9,833
5/17         $ 7,388                              $12,528


Call 1-800-225-6292 or visit www.amundipioneer.com for the most recent month-end
performance results. Current performance may be lower or higher than the
performance data quoted.

The performance data quoted represents past performance, which is no guarantee
of future results. Investment return and principal value will fluctuate, and
shares, when redeemed, may be worth more or less than their original cost.

Class C shares held for less than one year are also subject to a 1% contingent
deferred sales charge (CDSC). "If Held" results represent the percent change in
net asset value per share. Returns would have been lower had sales charges been
reflected. All results are historical and assume the reinvestment of dividends
and capital gains. Other share classes are available for which performance and
expenses will differ.

Performance results reflect any applicable expense waivers in effect during the
periods shown. Without such waivers Fund performance would be lower. Waivers may
not be in effect for all funds. Certain fee waivers are contractual through a
specified period. Otherwise, fee waivers can be rescinded at any time. See the
prospectus and financial statements for more information.

The net expense ratio reflects the contractual expense limitation currently in
effect through April 1, 2018, for Class C shares. There can be no assurance that
Amundi Pioneer will extend the expense limitation beyond such time. Please see
the prospectus and financial statements for more information.

The performance table and graph do not reflect the deduction of fees and taxes
that a shareowner would pay on Fund distributions or the redemption of Fund
shares.

Please refer to the financial highlights for a more current expense ratio.

12 Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17


Performance Update | 5/31/17                                      Class R Shares

Investment Returns
--------------------------------------------------------------------------------
The mountain chart on the right shows the change in value of a $10,000
investment made in Class R shares of Pioneer Emerging Markets Fund during the
periods shown, compared to that of the Morgan Stanley Capital International
(MSCI) Emerging Markets ND Index.



Average Annual Total Returns
(As of May 31, 2017)
--------------------------------------------------------------------------------

                       Net               MSCI
                       Asset             Emerging
                       Value             Markets
Period                 (NAV)             ND Index
--------------------------------------------------------------------------------
                                   
10 Years               -2.38%             2.28%
5 Years                 1.47              4.54
1 Year                 23.28             27.41
--------------------------------------------------------------------------------


Expense Ratio
(Per prospectus dated April 1, 2017)
--------------------------------------------------------------------------------
                       Gross             Net
--------------------------------------------------------------------------------
                                   
                       2.41%             2.20%
--------------------------------------------------------------------------------


[THE FOLLOWING DATA WAS REPRESENTED AS A MOUNTAIN CHART IN THE PRINTED MATERIAL]

Value of $10,000 Investment



             Pioneer Emerging Markets Fund        MSCI Emerging Markets ND Index
                                            
5/07        $10,000                               $10,000
5/08        $11,865                               $12,167
5/09        $ 6,830                               $ 7,987
5/10        $ 7,869                               $ 9,675
5/11        $10,020                               $12,595
5/12        $ 7,307                               $10,035
5/13        $ 7,838                               $11,450
5/14        $ 8,432                               $11,939
5/15        $ 7,511                               $11,938
5/16        $ 6,376                               $ 9,833
5/17        $ 7,861                               $12,528


Call 1-800-225-6292 or visit www.amundipioneer.com for the most recent month-end
performance results. Current performance may be lower or higher than the
performance data quoted.

The performance data quoted represents past performance, which is no guarantee
of future results. Investment return and principal value will fluctuate, and
shares, when redeemed, may be worth more or less than their original cost.

Class R shares are not subject to sales charges and are available for limited
groups of eligible investors, including institutional investors. All results are
historical and assume the reinvestment of dividends and capital gains. Other
share classes are available for which performance and expenses will differ.

Performance results reflect any applicable expense waivers in effect during the
periods shown. Without such waivers Fund performance would be lower. Waivers may
not be in effect for all funds. Certain fee waivers are contractual through a
specified period. Otherwise, fee waivers can be rescinded at any time. See the
prospectus and financial statements for more information.

The net expense ratio reflects the contractual expense limitation currently in
effect through April 1, 2018, for Class R shares. There can be no assurance that
Amundi Pioneer will extend the expense limitation beyond such time. Please see
the prospectus and financial statements for more information.

The performance table and graph do not reflect the deduction of fees and taxes
that a shareowner would pay on Fund distributions or the redemption of Fund
shares.

Please refer to the financial highlights for a more current expense ratio.

                  Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17 13


Performance Update | 5/31/17                                      Class Y Shares

Investment Returns
--------------------------------------------------------------------------------
The mountain chart on the right shows the change in value of a $5 million
investment made in Class Y shares of Pioneer Emerging Markets Fund during the
periods shown, compared to that of the Morgan Stanley Capital International
(MSCI) Emerging Markets ND Index.



Average Annual Total Returns
(As of May 31, 2017)
--------------------------------------------------------------------------------
                       Net               MSCI
                       Asset             Emerging
                       Value             Markets
Period                 (NAV)             ND Index
--------------------------------------------------------------------------------
                                   
10 Years               -1.71%             2.28%
5 Years                 2.08              4.54
1 Year                 23.81             27.41
--------------------------------------------------------------------------------


Expense Ratio
(Per prospectus dated April 1, 2017)
--------------------------------------------------------------------------------
                       Gross
--------------------------------------------------------------------------------
                    
                       1.76%
--------------------------------------------------------------------------------


[THE FOLLOWING DATA WAS REPRESENTED AS A MOUNTAIN CHART IN THE PRINTED MATERIAL]

Value of $5 Million Investment




           Pioneer Emerging Markets Fund          MSCI Emerging Markets ND Index
                                            
5/07       $5,000,000                             $5,000,000
5/08       $5,976,681                             $6,083,625
5/09       $3,464,971                             $3,993,494
5/10       $4,017,507                             $4,837,339
5/11       $5,153,460                             $6,297,343
5/12       $3,793,679                             $5,017,680
5/13       $4,099,021                             $5,725,164
5/14       $4,443,753                             $5,969,375
5/15       $3,984,354                             $5,968,953
5/16       $3,396,855                             $4,916,566
5/17       $4,205,810                             $6,264,122


Call 1-800-225-6292 or visit www.amundipioneer.com for the most recent month-end
performance results. Current performance may be lower or higher than the
performance data quoted.

The performance data quoted represents past performance, which is no guarantee
of future results. Investment return and principal value will fluctuate, and
shares, when redeemed, may be worth more or less than their original cost.

Class Y shares are not subject to sales charges and are available for limited
groups of eligible investors, including institutional investors. All results are
historical and assume the reinvestment of dividends and capital gains. Other
share classes are available for which performance and expenses will differ.

Performance results reflect any applicable expense waivers in effect during the
periods shown. Without such waivers Fund performance would be lower. Waivers may
not be in effect for all funds. Certain fee waivers are contractual through a
specified period. Otherwise, fee waivers can be rescinded at any time. See the
prospectus and financial statements for more information.

The performance table and graph do not reflect the deduction of fees and taxes
that a shareowner would pay on Fund distributions or the redemption of Fund
shares.

Please refer to the financial highlights for a more current expense ratio.

14 Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17


Comparing Ongoing Fund Expenses

As a shareowner in the Fund, you incur two types of costs:

(1)  ongoing costs, including management fees, distribution and/or service
     (12b-1) fees, and other Fund expenses; and

(2)  transaction costs, including sales charges (loads) on purchase payments.

This example is intended to help you understand your ongoing expenses (in
dollars) of investing in the Fund and to compare these costs with the ongoing
costs of investing in other mutual funds. The example is based on an investment
of $1,000 at the beginning of the Fund's latest six-month period and held
throughout the six months.

Using the Tables
--------------------------------------------------------------------------------
Actual Expenses

The first table below provides information about actual account values and
actual expenses. You may use the information in this table, together with the
amount you invested, to estimate the expenses that you paid over the period as
follows:

(1)  Divide your account value by $1,000
     Example: an $8,600 account value (divided by) $1,000 = 8.6

(2)  Multiply the result in (1) above by the corresponding share class's number
     in the third row under the heading entitled "Expenses Paid During Period"
     to estimate the expenses you paid on your account during this period.

Expenses Paid on a $1,000 Investment in Pioneer Emerging Markets Fund

Based on actual returns from December 1, 2016 through May 31, 2017.



--------------------------------------------------------------------------------
Share Class                    A             C               R             Y
--------------------------------------------------------------------------------
                                                           
Beginning Account Value    $1,000.00     $1,000.00       $1,000.00     $1,000.00
on 12/1/16
--------------------------------------------------------------------------------
Ending Account Value       $1,234.30     $1,228.60       $1,232.80     $1,235.40
(after expenses)
on 5/31/17
--------------------------------------------------------------------------------
Expenses Paid              $   10.86     $   15.84       $   12.25     $    9.47
During Period*
--------------------------------------------------------------------------------


*    Expenses are equal to the Fund's annualized net expense ratio of 1.95%,
     2.85%, 2.20% and 1.70% for Class A, Class C, Class R and Class Y shares,
     respectively, multiplied by the average account value over the period,
     multiplied by 182/365 (to reflect the one-half year period).

                  Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17 15


Hypothetical Example for Comparison Purposes

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 this 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 tables are meant to highlight your
ongoing costs only and do not reflect any transaction costs, such as sales
charges (loads), that are charged at the time of the transaction. Therefore, the
table below 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 transaction costs were included, your costs would have been higher.

Expenses Paid on a $1,000 Investment in Pioneer Emerging Markets Fund

Based on a hypothetical 5% return per year before expenses, reflecting the
period from December 1, 2016 through May 31, 2017.



--------------------------------------------------------------------------------
Share Class                   A               C            R               Y
--------------------------------------------------------------------------------
                                                           
Beginning Account Value    $1,000.00       $1,000.00    $1,000.00      $1,000.00
on 12/1/16
--------------------------------------------------------------------------------
Ending Account Value       $1,015.21       $1,010.72    $1,013.96      $1,016.45
(after expenses)
on 5/31/17
--------------------------------------------------------------------------------
Expenses Paid              $    9.80       $   14.29    $   11.05      $    8.55
During Period*
--------------------------------------------------------------------------------


*    Expenses are equal to the Fund's annualized net expense ratio of 1.95%,
     2.85%, 2.20% and 1.70% for Class A, Class C, Class R and Class Y shares,
     respectively, multiplied by the average account value over the period,
     multiplied by 182/365 (to reflect the one-half year period).

16 Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17


Schedule of Investments | 5/31/17 (unaudited)



--------------------------------------------------------------------------------------------
 Shares                                                                         Value
--------------------------------------------------------------------------------------------
                                                                          
                  PREFERRED STOCKS -- 4.1%
                  TECHNOLOGY HARDWARE & EQUIPMENT -- 4.1%
                  Technology Hardware, Storage & Peripherals -- 4.1%
       3,108      Samsung Electronics Co, Ltd.                                  $  4,831,673
                                                                                ------------
                  Total Technology Hardware & Equipment                         $  4,831,673
--------------------------------------------------------------------------------------------
                  TOTAL PREFERRED STOCKS
                  (Cost $3,241,355)                                             $  4,831,673
--------------------------------------------------------------------------------------------
                  COMMON STOCKS -- 92.1%
                  ENERGY -- 7.5%
                  Oil & Gas Equipment & Services -- 5.5%
   1,064,031      TMK PJSC (G.D.R.)                                             $  6,444,276
--------------------------------------------------------------------------------------------
                  Integrated Oil & Gas -- 0.6%
     165,060      Gazprom PJSC (A.D.R.)                                         $    688,867
--------------------------------------------------------------------------------------------
                  Oil & Gas Refining & Marketing -- 1.4%
  14,290,872      KenolKobil, Ltd. Group                                        $  1,726,363
                                                                                ------------
                  Total Energy                                                  $  8,859,506
--------------------------------------------------------------------------------------------
                  MATERIALS -- 2.1%
                  Construction Materials -- 0.8%
   6,212,000      West China Cement, Ltd.                                       $    908,608
--------------------------------------------------------------------------------------------
                  Aluminum -- 1.0%
   2,502,000      Aluminum Corp of China, Ltd.*                                 $  1,165,468
--------------------------------------------------------------------------------------------
                  Steel -- 0.3%
   1,054,000      Maanshan Iron & Steel                                         $    371,668
                                                                                ------------
                  Total Materials                                               $  2,445,744
--------------------------------------------------------------------------------------------
                  CAPITAL GOODS -- 3.7%
                  Construction & Engineering -- 1.8%
   3,595,000      Beijing Urban Construction Design & Development
                  Group Co, Ltd.                                                $  2,084,777
--------------------------------------------------------------------------------------------
                  Industrial Machinery -- 1.9%
   1,158,000      China Conch Venture Holdings, Ltd.*                           $  2,238,559
                                                                                ------------
                  Total Capital Goods                                           $  4,323,336
--------------------------------------------------------------------------------------------
                  AUTOMOBILES & COMPONENTS -- 4.9%
                  Auto Parts & Equipment -- 4.9%
   1,292,671      Tupy SA                                                       $  5,799,704
                                                                                ------------
                  Total Automobiles & Components                                $  5,799,704
--------------------------------------------------------------------------------------------
                  CONSUMER DURABLES & APPAREL -- 4.1%
                  Leisure Products -- 4.1%
   9,775,000      Goodbaby International Holdings, Ltd.                         $  4,778,626
                                                                                ------------
                  Total Consumer Durables & Apparel                             $  4,778,626
--------------------------------------------------------------------------------------------


The accompanying notes are an integral part of these financial statements.

                  Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17 17


Schedule of Investments | 5/31/17 (unaudited) (continued)



--------------------------------------------------------------------------------------------
 Shares                                                                         Value
--------------------------------------------------------------------------------------------
                                                                          
                  CONSUMER SERVICES -- 0.0%+
                  Casinos & Gaming -- 0.0%+
         393      NagaCorp, Ltd.                                                $        202
                                                                                ------------
                  Total Consumer Services                                       $        202
--------------------------------------------------------------------------------------------
                  MEDIA -- 5.0%
                  Cable & Satellite -- 5.0%
      28,464      Naspers, Ltd.                                                 $  5,890,086
                                                                                ------------
                  Total Media                                                   $  5,890,086
--------------------------------------------------------------------------------------------
                  FOOD, BEVERAGE & TOBACCO -- 8.3%
                  Brewers -- 3.9%
      38,749      Anheuser-Busch InBev SA/NV                                    $  4,579,477
--------------------------------------------------------------------------------------------
                  Packaged Foods & Meats -- 4.4%
   2,685,226      Marfrig Global Foods SA*                                      $  5,227,242
                                                                                ------------
                  Total Food, Beverage & Tobacco                                $  9,806,719
--------------------------------------------------------------------------------------------
                  BANKS -- 24.2%
                  Diversified Banks -- 24.2%
   3,891,000      China Construction Bank Corp.                                 $  3,214,303
   3,901,754      Eurobank Ergasias SA                                             3,955,084
         196      HDFC Bank, Ltd.                                                      4,983
      58,693      HDFC Bank, Ltd. (A.D.R.)                                         5,153,245
         415      Mega Financial Holding Co., Ltd.                                       333
   3,646,464      National Bank of Greece SA                                       1,277,658
   4,010,379      Philippine National Bank*                                        5,476,939
      53,238      Shinhan Financial Group Co., Ltd.                                2,352,775
 290,669,939      United Bank for Africa Plc                                       7,149,266
                                                                                ------------
                                                                                $ 28,584,586
                                                                                ------------
                  Total Banks                                                   $ 28,584,586
--------------------------------------------------------------------------------------------
                  DIVERSIFIED FINANCIALS -- 0.0%+
                  Consumer Finance -- 0.0%+
       2,753      Credito Real SAB de CV SOFOM ER                               $      4,080
                                                                                ------------
                  Total Diversified Financials                                  $      4,080
--------------------------------------------------------------------------------------------
                  SOFTWARE & SERVICES -- 9.7%
                  Internet Software & Services -- 7.0%
      42,431      Alibaba Group Holding, Ltd. (A.D.R.)                          $  5,196,100
     547,031      ChinaCache International Holdings, Ltd. (A.D.R.)*                  503,269
      72,700      Tencent Holdings, Ltd.                                           2,495,418
                                                                                ------------
                                                                                $  8,194,787
--------------------------------------------------------------------------------------------
                  IT Consulting & Other Services -- 2.7%
  37,093,000      China ITS Holdings Co., Ltd.                                  $  3,239,664
                                                                                ------------
                  Total Software & Services                                     $ 11,434,451
--------------------------------------------------------------------------------------------


The accompanying notes are an integral part of these financial statements.

18 Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17




--------------------------------------------------------------------------------------------
 Shares                                                                         Value
--------------------------------------------------------------------------------------------
                                                                          
                  TECHNOLOGY HARDWARE & EQUIPMENT -- 4.4%
                  Electronic Manufacturing Services -- 4.4%
   1,508,886      Hon Hai Precision Industry Co., Ltd.                          $  5,137,356
                                                                                ------------
                  Total Technology Hardware & Equipment                         $  5,137,356
--------------------------------------------------------------------------------------------
                  SEMICONDUCTORS & SEMICONDUCTOR
                  EQUIPMENT -- 13.9%
                  Semiconductor Equipment -- 5.1%
     228,518      Wonik IPS Co., Ltd.                                           $  5,968,335
--------------------------------------------------------------------------------------------
                  Semiconductors -- 8.8%
     105,578      S.O.I.T.E.C. SA                                               $  5,832,541
     687,000      Taiwan Semiconductor Manufacturing Co., Ltd.                     4,612,957
                                                                                ------------
                                                                                $ 10,445,498
                                                                                ------------
                  Total Semiconductors & Semiconductor Equipment                $ 16,413,833
--------------------------------------------------------------------------------------------
                  TELECOMMUNICATION SERVICES -- 4.3%
                  Wireless Telecommunication Services -- 4.3%
   6,976,578      Global Telecom Holding SAE*                                   $  2,516,964
     819,975      TIM Participacoes SA                                             2,513,411
                                                                                ------------
                                                                                $  5,030,375
                                                                                ------------
                  Total Telecommunication Services                              $  5,030,375
--------------------------------------------------------------------------------------------
                  Real Estate -- 0.0%+
                  Real Estate Services -- 0.0%+
      67,333      China Overseas Property Holdings, Ltd.                        $     11,834
                                                                                ------------
                  Total Real Estate                                             $     11,834
--------------------------------------------------------------------------------------------
                  TOTAL COMMON STOCKS
                  (Cost $103,377,007)                                           $108,520,438
--------------------------------------------------------------------------------------------


--------------------------------------------------------------------------------------------
Principal
Amount($)(d)
--------------------------------------------------------------------------------------------
                                                                          
                  CORPORATE BONDS -- 0.0%+
                  PHARMACEUTICALS, BIOTECHNOLOGY &
                  LIFE SCIENCES -- 0.0%+
                  Pharmaceuticals -- 0.0%+
BRL  562,000      Hypermarcas SA,, 11.3%, 10/15/18 (c)                          $     35,014
                                                                                ------------
                  Total Pharmaceuticals, Biotechnology &
                  Life Sciences                                                 $     35,014
--------------------------------------------------------------------------------------------
                  TOTAL CORPORATE BONDS
                  (Cost $164,597)                                               $     35,014
--------------------------------------------------------------------------------------------


The accompanying notes are an integral part of these financial statements.

                  Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17 19


Schedule of Investments | 5/31/17 (unaudited) (continued)



--------------------------------------------------------------------------------------------
 Shares                                                                         Value
--------------------------------------------------------------------------------------------
                                                                          
                  RIGHTS / WARRANTS -- 0.0%+
                  Food, Beverage & Tobacco -- 0.0%+
                  Packaged Foods & Meats -- 0.0%+
      39,707      Flour Mills of Nigeria Plc, 12/31/49 (c)                      $         --
                                                                                ------------
                  Total Food, Beverage & Tobacco                                $         --
--------------------------------------------------------------------------------------------
                  TOTAL RIGHTS / WARRANTS
                  (Cost $--)                                                    $         --
--------------------------------------------------------------------------------------------
                  TOTAL INVESTMENT IN SECURITIES -- 96.2%
                  (Cost $106,782,959) (a) (b)                                   $113,387,125
--------------------------------------------------------------------------------------------
                  OTHER ASSETS & LIABILITIES -- 3.8%                            $  4,475,796
--------------------------------------------------------------------------------------------
                  NET ASSETS -- 100.0%                                          $117,862,921
============================================================================================


+            Amount rounds to less than 0.1%.

*            Non-income producing security.

(A.D.R.)     American Depositary Receipts.

(G.D.R.)     Global Depositary Receipts.

(a)          At May 31, 2017, the net unrealized appreciation on investments
             based on cost for federal income tax purposes of $112,526,486 was
             as follows:



                                                                             
             Aggregate gross unrealized appreciation for all investments in
               which there is an excess of value over tax cost                  $ 16,953,193

             Aggregate gross unrealized depreciation for all investments in
               which there is an excess of tax cost over value                   (16,092,554)
                                                                                ------------
             Net unrealized appreciation                                        $    860,639
                                                                                ============


(b)          Distributions of investments by country of domicile (excluding
             temporary cash investments) as a percentage of total investment in
             securities, is as follows: China 23.1%


                                                                     
              Brazil                                                    12.0
              South Korea                                               11.6
              Taiwan                                                     8.6
              Russia                                                     6.3
              Nigeria                                                    6.3
              France                                                     5.2
              South Africa                                               5.2
              Philippines                                                4.8
              Greece                                                     4.6
              India                                                      4.5
              Belgium                                                    4.1
              Egypt                                                      2.2
              Kenya                                                      1.5
                                                                       -----
                                                                       100.0%
                                                                       =====


(c)           Security is valued using fair value methods (other than prices
              supplied by independent pricing services or broker-dealers). See
              Notes to Financial Statements -- Note 1A.

The accompanying notes are an integral part of these financial statements.

20 Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17


(d)           Principal amounts are denominated in U.S. Dollars unless
              otherwise noted:

              BRL   Brazilian Real

Purchases and sales of securities (excluding temporary cash investments) for the
six months ended May 31, 2017, aggregated $39,193,129 and $48,444,553,
respectively.

The Fund is permitted to engage in purchase and sale transactions ("cross
trades") with certain Funds and accounts for which Amundi Pioneer Asset
Management, Inc. (Amundi Pioneer), formerly Pioneer Investment Management, Inc.
(PIM), serves as the Fund's investment adviser, as set forth in Rule 17a-7 under
the Investment Company Act of 1940, pursuant to procedures adopted by the Board
of Trustees. Under these procedures, cross trades are effected at current market
prices. During the six months ended May 31, 2017, the Portfolio did not engage
in cross trade activity.

Various inputs are used in determining the value of the Fund's investments.
These inputs are summarized in the three broad levels listed below.

     Level 1 - quoted prices in active markets for identical securities.

     Level 2 - other significant observable inputs (Including quoted prices for
               similar securities, interest rates, prepayment speeds, credit
               risk, etc.) See Notes to Financial Statements -- Note 1A.

     Level 3 - significant unobservable inputs (Including the Fund's own
               assumptions in determining fair value of investments) See Notes
               to Financial Statements -- Note 1A.

The following is a summary of the inputs used as of May 31, 2017, in valuing the
Fund's investments:



--------------------------------------------------------------------------------------------
                                 Level 1         Level 2          Level 3     Total
--------------------------------------------------------------------------------------------
                                                                  
Preferred Stocks                 $        --     $  4,831,673     $      --   $    4,831,673
Common Stocks*
  Automobiles & Components
     Auto Parts & Equipment        5,799,704               --            --        5,799,704
  Food, Beverage & Tobacco
    Packaged Foods & Meats         5,227,242               --            --        5,227,242
  Banks
     Diversified Banks             5,153,245       23,431,341            --       28,584,586
  Diversified Financials
     Consumer Finance                  4,080               --            --            4,080
  Software & Services
     Internet Software &
      Services                     5,699,369        2,495,418            --        8,194,787
  Telecommunication Services
     Wireless Telecommunication
      Services                     2,513,411        2,516,964            --        5,030,375
  All Other Common Stocks                 --       55,679,664            --       55,679,664
Corporate Bond                            --               --        35,014           35,014
Right/Warrant                             --               --**          --               --
--------------------------------------------------------------------------------------------
Total                            $24,397,051     $ 88,955,060     $  35,014   $  113,387,125
============================================================================================


The accompanying notes are an integral part of these financial statements.

                  Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17 21


Schedule of Investments | 5/31/17 (unaudited) (continued)



-----------------------------------------------------------------------------
                              Level 1      Level 2       Level 3   Total
-----------------------------------------------------------------------------
                                                       
Other Financial Instruments
Unrealized appreciation on
 forward foreign
 currency contracts           $      --    $ 426,329     $    --   $ 426,329
Unrealized depreciation on
 forward foreign currency
 contracts                           --      (48,680)         --     (48,680)
Net unrealized appreciation
 on Futures Contracts           279,343           --          --     279,343
Net unrealized depreciation
 on futures Contracts          (164,007)          --          --    (164,007)
-----------------------------------------------------------------------------
Total                         $ 115,336    $ 377,649     $    --   $ 492,985
=============================================================================


*    Level 2 securities are valued using inputs/data furnished by independent
     pricing services using fair value factors.

**   Security is value at $0.

Following is a reconciliation of assets using significant unobservable inputs
(Level 3):



------------------------------------------------------------------------------------------
                                                         Corporate   Rights/
                                                         Bonds       Warrants    Totals
------------------------------------------------------------------------------------------
                                                                        
Balance as of 11/30/16                                   $ 43,347    --***       $ 43,347
Realized gain (loss)(1)                                        --    --                --
Change in unrealized appreciation (depreciation)(2)         6,411    --             6,411
Purchases                                                      --    --                --
Sales                                                     (14,744)   --           (14,744)
Changes between Level 3**                                      --    --                --
------------------------------------------------------------------------------------------
Balance as of 5/31/17                                    $ 35,014    --***       $ 35,014
==========================================================================================


(1)  Realized gain (loss) on these securities is included in the net realized
     gain (loss) on investments in the Statement of Operations.

(2)  Unrealized appreciation (depreciation) on these securities is included in
     the change in unrealized appreciation (depreciation) on investments in the
     Statement of Operations.

**   Transfers are calculated on the beginning of period values. During the six
     months ended May 31, 2017, there were no transfers between Levels 1, 2 and
     3.

***  Security is valued at $0.



                                                                       
     Net change in unrealized depreciation of Level 3 investments
     still held and considered Level 3 as of 5/31/17                      $6,411
                                                                          ------


The accompanying notes are an integral part of these financial statements.

22 Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17


Statement of Assets and Liabilities | 5/31/17 (unaudited)



                                                                                   
ASSETS:
  Investment in securities, at value (cost $106,782,959)                              $ 113,387,125
  Cash                                                                                    3,019,518
  Foreign currencies, at value (cost $1,486,208)                                          1,516,414
  Restricted cash*                                                                          783,658
  Receivables --
     Investment securities sold                                                           1,390,112
     Fund shares sold                                                                       144,927
     Interest                                                                                 2,141
     Dividends                                                                               87,699
  Variation margin for futures contracts                                                     49,906
  Unrealized appreciation on forward foreign currency contracts                             426,329
  Other assets                                                                               26,543
 --------------------------------------------------------------------------------------------------
        Total assets                                                                  $ 120,834,372
===================================================================================================
LIABILITIES:
  Payables --
     Investment securities purchased                                                  $   2,345,903
     Fund shares repurchased                                                                223,614
     Distributions                                                                              239
     Trustee fees                                                                             1,143
     Custody expense                                                                         38,090
  Unrealized depreciation on forward foreign currency contracts                              48,680
  Due to affiliates                                                                         165,662
  Accrued expenses                                                                          148,120
 --------------------------------------------------------------------------------------------------
        Total liabilities                                                             $   2,971,451
===================================================================================================
NET ASSETS:
  Paid-in capital                                                                     $ 143,910,731
  Distributions in excess of net investment income                                         (479,665)
  Accumulated net realized loss on investments, futures contracts and
     foreign currency transactions                                                      (32,698,490)
  Net unrealized appreciation on investments                                              6,604,166
  Net unrealized appreciation on futures contracts                                          115,336
  Net unrealized appreciation on forward foreign currency contracts and
     other assets and liabilities denominated in foreign currencies                         410,843
 --------------------------------------------------------------------------------------------------
        Net assets                                                                    $ 117,862,921
===================================================================================================
NET ASSET VALUE PER SHARE:
(No par value, unlimited number of shares authorized)
  Class A (based on $74,717,051/3,723,684 shares)                                     $       20.07
  Class C (based on $13,417,999/821,085 shares)                                       $       16.34
  Class R (based on $22,579,413/1,181,054 shares)                                     $       19.12
  Class Y (based on $7,148,458/321,943 shares)                                        $       22.20
MAXIMUM OFFERING PRICE:
  Class A ($20.07 (divided by) 94.25%)                                                $       21.29
===================================================================================================


*    Represents restricted cash deposited at the custodian and/or counterparty
     for derivative contracts.

The accompanying notes are an integral part of these financial statements.

                  Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17 23


Statement of Operations (unaudited)

For the Six Months Ended 5/31/17



                                                                                  
INVESTMENT INCOME:
  Dividends (net of foreign taxes withheld of $110,666)               $      802,686
  Interest (net of foreign taxes withheld of $1,492)                           4,591
-----------------------------------------------------------------------------------------------------
         Total investment income                                                        $    807,277
-----------------------------------------------------------------------------------------------------
EXPENSES:
  Management fees                                                     $      577,624
  Transfer agent fees
     Class A                                                                  91,364
     Class C                                                                  16,709
     Class R                                                                  30,972
     Class Y                                                                   2,663
  Distribution fees
     Class A                                                                  85,291
     Class C                                                                  58,674
     Class R                                                                  51,906
  Shareholder communications expense                                          39,723
  Administrative expense                                                      41,119
  Custodian fees                                                              92,590
  Registration fees                                                           31,624
  Professional fees                                                           21,277
  Printing expense                                                             8,153
  Fees and expenses of nonaffiliated Trustees                                  3,470
  Miscellaneous                                                               42,652
-----------------------------------------------------------------------------------------------------
     Total expenses                                                                     $  1,195,811
     Less fees waived and expenses reimbursed
        by Amundi Pioneer Asset Management, Inc. (Amundi
        Pioneer), formerly Pioneer Investment
        Management, Inc. (PIM)                                                               (98,360)
-----------------------------------------------------------------------------------------------------
     Net expenses                                                                       $  1,097,451
-----------------------------------------------------------------------------------------------------
        Net investment loss                                                             $   (290,174)
-----------------------------------------------------------------------------------------------------
REALIZED AND UNREALIZED GAIN (LOSS) ON INVESTMENTS,
FUTURES CONTRACTS AND FOREIGN CURRENCY TRANSACTIONS:
  Net realized gain (loss) on:
     Investments                                                      $    3,926,658
     Futures contracts                                                       274,966
     Forward foreign currency contracts and other assets
        and liabilities denominated in foreign currencies                 (1,357,743)   $  2,843,881
-----------------------------------------------------------------------------------------------------
  Change in net unrealized appreciation (depreciation) on:
     Investments                                                      $   18,315,441
     Futures contracts                                                       110,653
     Forward foreign currency contracts and other assets
        and liabilities denominated in foreign currencies                  1,048,457    $ 19,474,551
-----------------------------------------------------------------------------------------------------
  Net realized and unrealized gain (loss) on investments, futures
     contracts and foreign currency transactions                                        $ 22,318,432
-----------------------------------------------------------------------------------------------------
  Net increase in net assets resulting from operations                                  $ 22,028,258
=====================================================================================================


The accompanying notes are an integral part of these financial statements.

24 Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17


Statement of Changes in Net Assets



-------------------------------------------------------------------------------------------------
                                                                    Six Months
                                                                    Ended
                                                                    5/31/17        Year Ended
                                                                    (unaudited)    11/30/16
-------------------------------------------------------------------------------------------------
                                                                             
FROM OPERATIONS:
Net investment income (loss)                                        $   (290,174)  $     526,162
Net realized gain (loss) on investments, futures contracts
  and foreign currency transactions                                    2,843,881     (16,979,106)
Change in net unrealized appreciation (depreciation) on
  investments, futures contracts and foreign currency
  transactions                                                        19,474,551      22,234,571
-------------------------------------------------------------------------------------------------
       Net increase in net assets resulting
          from operations                                           $ 22,028,258   $   5,781,627
-------------------------------------------------------------------------------------------------
DISTRIBUTIONS TO SHAREOWNERS:
Net investment income:
       Class A ($0.00 and $0.53 per share, respectively)            $         --   $  (2,346,367)
       Class C ($0.00 and $0.40 per share, respectively)                      --        (380,674)
       Class R ($0.00 and $0.49 per share, respectively)                      --        (704,509)
       Class Y ($0.00 and $0.58 per share, respectively)                      --        (137,213)
-------------------------------------------------------------------------------------------------
       Total distributions to shareowners                           $         --   $  (3,568,763)
-------------------------------------------------------------------------------------------------
FROM FUND SHARE TRANSACTIONS:
Net proceeds from sale or exchange of shares                        $ 12,818,127   $  14,077,225
Reinvestment of distributions                                                 --       3,419,408
Cost of shares repurchased                                           (17,884,287)    (28,448,457)
-------------------------------------------------------------------------------------------------
       Net decrease in net assets resulting from
          Fund share transactions                                   $ (5,066,160)  $ (10,951,824)
-------------------------------------------------------------------------------------------------
       Net increase (decrease) in net assets                        $ 16,962,098   $  (8,738,960)
NET ASSETS:
Beginning of period                                                 $100,900,823   $ 109,639,783
-------------------------------------------------------------------------------------------------
End of period                                                       $117,862,921   $ 100,900,823
-------------------------------------------------------------------------------------------------
Distributions in excess of net investment income                    $   (479,665)  $    (189,491)
-------------------------------------------------------------------------------------------------


The accompanying notes are an integral part of these financial statements.

                  Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17 25


Statement of Changes in Net Assets (continued)



----------------------------------------------------------------------------------------
                                 Six Months   Six Months
                                 Ended        Ended
                                 5/31/17      5/31/17        Year Ended    Year Ended
                                 Shares       Amount         11/30/16      11/30/16
                                 (unaudited)  (unaudited)    Shares        Amount
----------------------------------------------------------------------------------------
                                                               
Class A
Shares sold                       300,393     $  5,607,864       532,389   $  8,379,950
Reinvestment of distributions          --               --       150,194      2,279,939
Less shares repurchased          (645,179)     (11,409,106)   (1,053,942)   (16,426,614)
----------------------------------------------------------------------------------------
      Net decrease               (344,786)    $ (5,801,242)     (371,359)  $ (5,766,725)
========================================================================================
Class C
Shares sold                       112,141     $  1,731,595       126,675   $  1,598,774
Reinvestment of distributions          --               --        27,726        347,126
Less shares repurchased          (130,613)      (1,905,347)     (275,202)    (3,481,532)
----------------------------------------------------------------------------------------
      Net decrease                (18,472)    $   (173,752)     (120,801)  $ (1,535,632)
========================================================================================
Class R
Shares sold                       108,641     $  1,907,543       219,086   $  3,245,633
Reinvestment of distributions          --               --        47,246        685,536
Less shares repurchased          (202,536)      (3,423,676)     (479,182)    (7,079,917)
----------------------------------------------------------------------------------------
      Net decrease                (93,895)    $ (1,516,133)     (212,850)  $ (3,148,748)
========================================================================================
Class Y
Shares sold                       167,292     $  3,571,125        48,713   $    852,868
Reinvestment of distributions          --               --         6,377        106,807
Less shares repurchased           (59,148)      (1,146,158)      (84,890)    (1,460,394)
----------------------------------------------------------------------------------------
      Net increase (decrease)     108,144     $  2,424,967       (29,800)  $   (500,719)
========================================================================================


The accompanying notes are an integral part of these financial statements.

26 Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17


Financial Highlights



-----------------------------------------------------------------------------------------------------------------------------------
                                                             Six Months
                                                             Ended        Year        Year         Year        Year       Year
                                                             5/31/17      Ended       Ended        Ended       Ended      Ended
                                                             (unaudited)  11/30/16    11/30/15     11/30/14    11/30/13   11/30/12
-----------------------------------------------------------------------------------------------------------------------------------
                                                                                                        
Class A
Net asset value, beginning of period                         $ 16.25      $ 15.85     $ 20.92      $  24.06    $  23.24   $  23.10
-----------------------------------------------------------------------------------------------------------------------------------
Increase (decrease) from investment operations:
   Net investment income (loss)                              $ (0.04)(a)  $  0.10(a)  $ (0.01)(a)  $  (0.04)   $   0.14   $   0.13
   Net realized and unrealized gain (loss) on investments       3.86         0.83       (4.35)        (1.61)       0.79       0.11
-----------------------------------------------------------------------------------------------------------------------------------
Net increase (decrease) from investment operations           $  3.82      $  0.93     $ (4.36)     $  (1.65)   $   0.93   $   0.24
-----------------------------------------------------------------------------------------------------------------------------------
Distribution to shareowners:
   Net investment income                                     $    --      $ (0.53)    $ (0.38)     $  (0.08)   $  (0.11)  $     --
   Net realized gain                                              --           --       (0.33)        (1.41)         --      (0.10)
-----------------------------------------------------------------------------------------------------------------------------------
Total distributions                                          $    --      $ (0.53)    $ (0.71)     $  (1.49)   $  (0.11)  $  (0.10)
-----------------------------------------------------------------------------------------------------------------------------------
Net increase (decrease) in net asset value                   $  3.82      $  0.40     $ (5.07)     $  (3.14)   $   0.82   $   0.14
-----------------------------------------------------------------------------------------------------------------------------------
Net asset value, end of period                               $ 20.07      $ 16.25     $ 15.85      $  20.92    $  24.06   $  23.24
===================================================================================================================================
Total return*                                                  23.43%        6.13%     (21.14)%       (6.88)%      3.98%      1.06%
Ratio of net expenses to average net assets (b)                 1.95%**      1.95%       1.95%         1.96%       1.95%      1.95%
Ratio of net investment income (loss) to average net assets    (0.41)%**     0.65%      (0.04)%       (0.19)%      0.55%      0.53%
Portfolio turnover rate                                           76%**        92%         85%          141%         77%       160%
Net assets, end of period (in thousands)                     $74,717      $66,127     $70,351      $104,251    $126,981   $154,064
Ratios with no waiver of fees and assumption of expenses by
   Amundi Pioneer, formerly PIM, and no reduction for fees
   paid indirectly:
   Total expenses to average net assets (b)                     2.18%**      2.28%       2.18%         2.04%       1.96%      2.03%
   Net investment income (loss) to average net assets          (0.64)%**     0.32%      (0.27)%       (0.26)%      0.54%      0.45%
===================================================================================================================================


*    Assumes initial investment at net asset value at the beginning of each
     period, reinvestment of all distributions, the complete redemption of the
     investment at net asset value at the end of each period and no sales
     charges. Total return would be reduced if sales charges were taken into
     account.

(a)  The per-share data presented above is based on the average shares
     outstanding for the period presented.

(b)  Includes interest expense of 0.00%, 0.00%, 0.00%, 0.01%, 0.00% and 0.00%,
     respectively.

**   Annualized.

The accompanying notes are an integral part of these financial statements.

                  Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17 27


Financial Highlights (continued)



-----------------------------------------------------------------------------------------------------------------------------------
                                                            Six Months
                                                            Ended        Year           Year         Year       Year       Year
                                                            5/31/17      Ended          Ended        Ended      Ended      Ended
                                                            (unaudited)  11/30/16       11/30/15     11/30/14   11/30/13   11/30/12
-----------------------------------------------------------------------------------------------------------------------------------
                                                                                                         
Class C
Net asset value, beginning of period                        $ 13.30      $ 13.04        $ 17.35      $ 20.32    $ 19.70    $ 19.76
-----------------------------------------------------------------------------------------------------------------------------------
Increase (decrease) from investment operations:
   Net investment income (loss)                             $ (0.09)(a)  $ (0.03)(a)(c) $ (0.14)(a)  $ (0.22)   $ (0.04)   $ (0.06)
   Net realized and unrealized gain (loss) on investments      3.13         0.69          (3.61)       (1.34)      0.66       0.10
-----------------------------------------------------------------------------------------------------------------------------------
Net increase (decrease) from investment operations          $  3.04      $  0.66        $ (3.75)     $ (1.56)   $  0.62    $  0.04
-----------------------------------------------------------------------------------------------------------------------------------
Distribution to shareowners:
   Net investment income                                    $    --      $ (0.40)       $ (0.23)     $    --    $    --    $    --
   Net realized gain                                             --           --          (0.33)       (1.41)        --      (0.10)
-----------------------------------------------------------------------------------------------------------------------------------
Total distributions                                         $    --      $ (0.40)       $ (0.56)     $ (1.41)   $    --    $ (0.10)
-----------------------------------------------------------------------------------------------------------------------------------
Net increase (decrease) in net asset value                  $  3.04      $  0.26        $ (4.31)     $ (2.97)   $  0.62    $ (0.06)
-----------------------------------------------------------------------------------------------------------------------------------
Net asset value, end of period                              $ 16.34      $ 13.30        $ 13.04      $ 17.35    $ 20.32    $ 19.70
===================================================================================================================================
Total return*                                                 22.86%        5.27%        (21.87)%      (7.69)%     3.15%      0.23%
Ratio of net expenses to average net assets (b)                2.85%**      2.85%          2.85%        2.80%      2.78%      2.75%
Ratio of net investment income (loss) to average net assets   (1.31)%**    (0.24)%        (0.93)%      (1.02)%    (0.27)%    (0.25)%
Portfolio turnover rate                                          76%**        92%            85%         141%        77%       160%
Net assets, end of period (in thousands)                    $13,418      $11,164        $12,523      $18,801    $23,810    $29,771
Ratios with no waiver of fees and assumption of expenses by
   Amundi Pioneer, formerly PIM, and no reduction for fees
   paid indirectly:
   Total expenses to average net assets (b)                    2.93%**      3.06%          2.95%        2.80%      2.78%      2.75%
   Net investment income (loss) to average net assets         (1.39)%**    (0.45)%        (1.03)%      (1.02)%    (0.27)%    (0.25)%
===================================================================================================================================


*    Assumes initial investment at net asset value at the beginning of each
     period, reinvestment of all distributions, the complete redemption of the
     investment at net asset value at the end of each period and no sales
     charges. Total return would be reduced if sales charges were taken into
     account.

(a)  The per-share data presented above is based on the average shares
     outstanding for the period presented.

(b)  Includes interest expense of 0.00%, 0.00%, 0.00%, 0.01%, 0.00% and 0.00%,
     respectively.

(c)  The amount shown for a share outstanding does not correspond with net
     investment income on the Statement of Operations for the period due to
     timing of the sales and repurchase of shares.

**   Annualized.

The accompanying notes are an integral part of these financial statements.

28 Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17




--------------------------------------------------------------------------------------------------------------------------------
                                                             Six Months
                                                             Ended        Year        Year         Year       Year      Year
                                                             5/31/17      Ended       Ended        Ended      Ended     Ended
                                                             (unaudited)  11/30/16    11/30/15     11/30/14   11/30/13  11/30/12
--------------------------------------------------------------------------------------------------------------------------------
                                                                                                      
Class R
Net asset value, beginning of period                         $ 15.51      $ 15.13     $ 20.02      $ 23.11    $ 22.30   $ 22.23
--------------------------------------------------------------------------------------------------------------------------------
Increase (decrease) from investment operations:
   Net investment income (loss)                              $ (0.06)(a)  $  0.06(a)  $ (0.05)(a)  $ (0.09)   $  0.10   $  0.10
   Net realized and unrealized gain (loss) on investments       3.67         0.81       (4.17)       (1.55)      0.76      0.07
--------------------------------------------------------------------------------------------------------------------------------
Net increase (decrease) from investment operations           $  3.61      $  0.87     $ (4.22)     $ (1.64)   $  0.86   $  0.17
--------------------------------------------------------------------------------------------------------------------------------
Distribution to shareowners:
   Net investment income                                     $    --      $ (0.49)    $ (0.34)     $ (0.04)   $ (0.05)  $    --
   Net realized gain                                              --           --       (0.33)       (1.41)        --     (0.10)
--------------------------------------------------------------------------------------------------------------------------------
Total distributions                                          $    --      $ (0.49)    $ (0.67)     $ (1.45)   $ (0.05)  $ (0.10)
--------------------------------------------------------------------------------------------------------------------------------
Net increase (decrease) in net asset value                   $  3.61      $  0.38     $ (4.89)     $ (3.09)   $  0.81   $  0.07
--------------------------------------------------------------------------------------------------------------------------------
Net asset value, end of period                               $ 19.12      $ 15.51     $ 15.13      $ 20.02    $ 23.11   $ 22.30
================================================================================================================================
Total return*                                                  23.28%        5.95%     (21.36)%      (7.10)%     3.86%     0.79%
Ratio of net expenses to average net assets (b)                 2.20%**      2.20%       2.20%        2.18%      2.13%     2.13%
Ratio of net investment income (loss) to average net assets    (0.66)%**     0.41%      (0.29)%      (0.40)%     0.37%     0.39%
Portfolio turnover rate                                           76%**        92%         85%         141%        77%      160%
Net assets, end of period (in thousands)                     $22,579      $19,769     $22,510      $33,742    $39,183   $49,013
Ratios with no waiver of fees and assumption of expenses by
   Amundi Pioneer, formerly PIM, and no reduction for fees
   paid indirectly:
   Total expenses to average net assets (b)                     2.36%**      2.41%       2.33%        2.18%      2.13%     2.13%
   Net investment income (loss) to average net assets          (0.82)%**     0.20%      (0.42)%      (0.40)%     0.37%     0.39%
================================================================================================================================


*    Assumes initial investment at net asset value at the beginning of each
     period, reinvestment of all distributions, the complete redemption of the
     investment at net asset value at the end of each period and no sales
     charges. Total return would be reduced if sales charges were taken into
     account.

(a)  The per-share data presented above is based on the average shares
     outstanding for the period presented.

(b)  Includes interest expense of 0.00%, 0.00%, 0.00%, 0.01%, 0.00% and 0.00%,
     respectively.

**   Annualized.

The accompanying notes are an integral part of these financial statements.

                  Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17 29


Financial Highlights (continued)



---------------------------------------------------------------------------------------------------------------------------------
                                                             Six Months
                                                             Ended        Year       Year           Year       Year      Year
                                                             5/31/17      Ended      Ended          Ended      Ended     Ended
                                                             (unaudited)  11/30/16   11/30/15       11/30/14   11/30/13  11/30/12
---------------------------------------------------------------------------------------------------------------------------------
                                                                                                       
Class Y
Net asset value, beginning of period                         $ 17.97      $17.47     $ 23.06        $ 26.38    $ 25.46   $ 25.16
---------------------------------------------------------------------------------------------------------------------------------
Increase (decrease) from investment operations:
   Net investment income (loss)                              $ (0.02)(a)  $ 0.14(a)  $  0.00(a)(b)  $  0.09    $  0.28   $  0.28
   Net realized and unrealized gain (loss) on investments       4.25        0.94       (4.75)         (1.77)      0.90      0.12
---------------------------------------------------------------------------------------------------------------------------------
Net increase (decrease) from investment operations           $  4.23      $ 1.08     $ (4.75)       $ (1.68)   $  1.18   $  0.40
---------------------------------------------------------------------------------------------------------------------------------
Distribution to shareowners:
   Net investment income                                     $    --      $(0.58)    $ (0.51)       $ (0.23)   $ (0.26)  $    --
   Net realized gain                                              --          --       (0.33)         (1.41)        --     (0.10)
---------------------------------------------------------------------------------------------------------------------------------
Total distributions                                          $    --      $(0.58)    $ (0.84)       $ (1.64)   $ (0.26)  $ (0.10)
---------------------------------------------------------------------------------------------------------------------------------
Net increase (decrease) in net asset value                   $  4.23      $ 0.50     $ (5.59)       $ (3.32)   $  0.92   $  0.30
---------------------------------------------------------------------------------------------------------------------------------
Net asset value, end of period                               $ 22.20      $17.97     $ 17.47        $ 23.06    $ 26.38   $ 25.46
=================================================================================================================================
Total return*                                                  23.54%       6.44%     (20.96)%        (6.41)%     4.63%     1.61%
Ratio of net expenses to average net assets (c)                 1.70%**     1.76%       1.55%          1.40%      1.38%     1.39%
Ratio of net investment income (loss) to average net assets    (0.20)%**    0.84%       0.01%          0.34%      1.12%     1.10%
Portfolio turnover rate                                           76%**       92%         85%           141%        77%      160%
Net assets, end of period (in thousands)                     $ 7,148      $3,841     $ 4,256        $35,835    $65,655   $62,897
=================================================================================================================================


*    Assumes initial investment at net asset value at the beginning of each
     period, reinvestment of all distributions, the complete redemption of the
     investment at net asset value at the end of each period.

(a)  The per-share data presented above is based on the average shares
     outstanding for the period presented.

(b)  Amount rounds to less than $0.01 or $(0.01) per share.

(c)  Includes interest expense of 0.00%, 0.00%, 0.00%, 0.01%, 0.00% and 0.00%,
     respectively.

**   Annualized.

The accompanying notes are an integral part of these financial statements.

30 Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17

Notes to Financial Statements | 5/31/17 (unaudited)

1. Organization and Significant Accounting Policies

Pioneer Emerging Markets Fund (the Fund) is a Delaware statutory trust. The Fund
is registered under the Investment Company Act of 1940 as a diversified,
open-end management investment company. The investment objective of the Fund is
long-term growth of capital.

The Fund offers four classes of shares designated as Class A, Class C, Class R,
and Class Y shares. Each class of shares represents an interest in the same
portfolio of investments of the Fund and has identical rights (based on relative
net asset values) to assets and liquidation proceeds. Share classes can bear
different rates of class-specific fees and expenses such as transfer agent and
distribution fees. Differences in class-specific fees and expenses will result
in differences in net investment income and, therefore, the payment of different
dividends from net investment income earned by each class. The Amended and
Restated Declaration of Trust of the Fund gives the Board of Trustees the
flexibility to specify either per-share voting or dollar-weighted voting when
submitting matters for shareholder approval. Under per-share voting, each share
of a class of the Fund is entitled to one vote. Under dollar-weighted voting, a
shareholder's voting power is determined not by the number of shares owned, but
by the dollar value of the shares on the record date. Each share class has
exclusive voting rights with respect to matters affecting only that class,
including with respect to the distribution plan for that class. There is no
distribution plan for Class Y shares.

On July 3, 2017, Amundi acquired Pioneer Investments, a group of asset
management companies located throughout the world. Amundi, one of the world's
largest asset managers, is headquartered in Paris, France. As a result of the
transaction, Pioneer Investment Management, Inc., the Fund's investment adviser,
became an indirect wholly owned subsidiary of Amundi and Amundi's wholly owned
subsidiary, Amundi USA, Inc. Prior to July 3, 2017, Pioneer Investments was
owned by Pioneer Global Asset Management S.p.A., a wholly owned subsidiary of
UniCredit S.p.A.

In connection with the transaction, the names of the Fund's investment adviser
and principal underwriter changed. Effective July 3, 2017, the name of Pioneer
Investment Management, Inc. changed to Amundi Pioneer Asset Management, Inc. and
the name of Pioneer Funds Distributor, Inc. changed to Amundi Pioneer
Distributor, Inc.

The Fund's financial statements have been prepared in conformity with U.S.
generally accepted accounting principles (U.S. GAAP) that require the management
of the Fund to make estimates and assumptions that affect the reported amounts
of assets and liabilities, the disclosure of contingent assets

                  Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17 31


and liabilities at the date of the financial statements, and the reported
amounts of income, expenses and gain or loss on investments during the reporting
period. Actual results could differ from those estimates.

The Fund is an investment company and follows investment company accounting and
reporting guidance under U.S. GAAP. The following is a summary of significant
accounting policies followed by the Fund in the preparation of its financial
statements:

A.   Security Valuation

     The net asset value of the Fund is computed once daily, on each day the New
     York Stock Exchange (NYSE) is open, as of the close of regular trading on
     the NYSE.

     Equity securities that have traded on an exchange are valued by using the
     last sale price on the principal exchange where they are traded. Equity
     securities that have not traded on the date of valuation, or securities for
     which sale prices are not available, generally are valued using the mean
     between the last bid and asked prices or, if both last bid and asked prices
     are not available, at the last quoted bid price. Last sale and bid and
     asked prices are provided by independent third party pricing services. In
     the case of equity securities not traded on an exchange, prices are
     typically determined by independent third party pricing services using a
     variety of techniques and methods.

     The principal exchanges and markets for non-U.S. equity securities have
     closing times prior to the close of the NYSE. However, the value of these
     securities may be influenced by changes in global markets occurring after
     the closing times of the local exchanges and markets up to the time the
     Fund determines its net asset value. Consequently, the Fund uses a fair
     value model developed by an independent pricing service to value non-U.S.
     equity securities. On a daily basis, the pricing service recommends
     changes, based on a proprietary model, to the closing market prices of each
     non-U.S. security held by the Fund to reflect the security's fair value at
     the time the Fund determines its net asset value. The Fund applies these
     recommendations in accordance with procedures approved by the Board of
     Trustees.

     Fixed-income securities are valued by using prices supplied by independent
     pricing services, which consider such factors as market prices, market
     events, quotations from one or more brokers, Treasury spreads, yields,
     maturities and ratings, or may use a pricing matrix or other fair value
     methods or techniques to provide an estimated value of the security or
     instrument. A pricing matrix is a means of valuing a debt security on the
     basis of current market prices for other debt securities, historical
     trading patterns in the market for fixed-income securities and/or other
     factors. Non-U.S. debt securities that are listed on an exchange will be
     valued at the bid price obtained from an independent

32 Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17


     third party pricing service. When independent third party pricing services
     are unable to supply prices, or when prices or market quotations are
     considered to be unreliable, the value of that security may be determined
     using quotations from one or more broker-dealers.

     Futures contracts are generally valued at the closing settlement price
     established by the exchange on which they are traded.

     Forward foreign currency exchange contracts are valued daily using the
     foreign exchange rate or, for longer term forward contract positions, the
     spot currency rate and the forward points on a daily basis, in each case
     provided by a third party pricing service. Contracts whose forward
     settlement date falls between two quoted days are valued by interpolation.

     Securities for which independent pricing services or broker-dealers are
     unable to supply prices or for which market prices and/or quotations are
     not readily available or are considered to be unreliable are valued by a
     fair valuation team comprised of certain personnel of Amundi Pioneer Asset
     Management, Inc. (Amundi Pioneer), formerly Pioneer Investment Management,
     Inc. (PIM), the Fund's investment adviser and pursuant to procedures
     adopted by the Board of Trustees. Amundi Pioneer's, formerly PIM's, fair
     valuation team uses fair value methods approved by the Valuation Committee
     of the Board of Trustees. Amundi Pioneer's, formerly PIM's, fair valuation
     team is responsible for monitoring developments that may impact fair valued
     securities and for discussing and assessing fair values on an ongoing
     basis, and at least quarterly, with the Valuation Committee of the Board of
     Trustees.

     Inputs used when applying fair value methods to value a security may
     include credit ratings, the financial condition of the company, current
     market conditions and comparable securities. The Fund may use fair value
     methods if it is determined that a significant event has occurred after the
     close of the exchange or market on which the security trades and prior to
     the determination of the Fund's net asset value. Examples of a significant
     event might include political or economic news, corporate restructurings,
     natural disasters, terrorist activity or trading halts. Thus, the valuation
     of the Fund's securities may differ significantly from exchange prices and
     such differences could be material.

     At May 31, 2017, two securities were valued using fair value methods (in
     addition to securities valued using prices supplied by independent pricing
     services) representing 0.03% of net assets.

                  Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17 33


B.   Investment Income and Transactions

     Dividend income is recorded on the ex-dividend date, except that certain
     dividends from foreign securities where the ex-dividend date may have
     passed are recorded as soon as the Fund becomes aware of the ex-dividend
     data in the exercise of reasonable diligence. Interest income, including
     interest on income-bearing cash accounts, is recorded on the accrual basis.
     Dividend and interest income are reported net of unrecoverable foreign
     taxes withheld at the applicable country rates.

     Security transactions are recorded as of trade date. Gains and losses on
     sales of investments are calculated on the identified cost method for both
     financial reporting and federal income tax purposes.

C.   Foreign Currency Translation

     The books and records of the Fund are maintained in U.S. dollars. Amounts
     denominated in foreign currencies are translated into U.S. dollars using
     current exchange rates.

     Net realized gains and losses on foreign currency transactions, if any,
     represent, among other things, the net realized gains and losses on foreign
     currency contracts, disposition of foreign currencies and the difference
     between the amount of income accrued and the U.S. dollars actually
     received. Further, the effects of changes in foreign currency exchange
     rates on investments are not segregated in the Statement of Operations from
     the effects of changes in the market price of those securities but are
     included with the net realized and unrealized gain or loss on investments.

D.   Forward Foreign Currency Contracts

     The Fund may enter into forward foreign currency contracts (contracts) for
     the purchase or sale of a specific foreign currency at a fixed price on a
     future date. All contracts are marked to market daily at the applicable
     exchange rates, and any resulting unrealized appreciation or depreciation
     is recorded in the Fund's financial statements. The Fund records realized
     gains and losses at the time a contract is offset by entry into a closing
     transaction or extinguished by delivery of the currency. Risks may arise
     upon entering into these contracts from the potential inability of
     counterparties to meet the terms of the contract and from unanticipated
     movements in the value of foreign currencies relative to the U.S. dollar
     (see Note 5).

E.   Futures Contracts

     The Fund may enter into futures transactions in order to attempt to hedge
     against changes in interest rates, securities prices and currency exchange
     rates or to seek to increase total return. Futures contracts are types of
     derivatives. All futures contracts entered into by the Fund are traded on a

34 Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17


     futures exchange. Upon entering into a futures contract, the Fund is
     required to deposit with a broker an amount of cash or securities equal to
     the minimum "initial margin" requirements of the associated futures
     exchange. The amount of cash due to the broker as collateral at May 31,
     2017 was $772,064 and is recorded within "Restricted Cash" on the Statement
     of Assets and Liabilities. Subsequent payments for futures contracts
     ("variation margin") are paid or received by the Fund, depending on the
     daily fluctuation in the value of the contracts, and are recorded by the
     Fund as unrealized gains or losses. When the contract is closed, the Fund
     realizes a gain or loss equal to the difference between the opening and
     closing value of the contract as well as any fluctuation in foreign
     currency exchange rates where applicable. The use of futures contracts
     involves, to varying degrees, elements of market, interest rate, currency
     exchange rate and counterparty risks, which may exceed the amounts
     recognized by the Fund. Changes in value of the contracts may not directly
     correlate to the changes in value of the underlying securities. The average
     value of contracts open for the six months ended May 31, 2017 was
     $2,714,762.

     At May 31, 2017, open futures contracts were as follows:



     ---------------------------------------------------------------------------------------

                                  Number of                                   Net Unrealized
                                  Contracts      Settlement                   Appreciation
     Description   Counterparty   Long/(Short)   Month        Value           (Depreciation)
     ---------------------------------------------------------------------------------------
                                                               
     BOVESPA
        Index      UBS AG         (105)          6/17         $(2,038,648)    $(164,007)
     KOS P12-
        Index      UBS AG         38             6/17           2,590,929       279,343
     ---------------------------------------------------------------------------------------
     Total                                                    $   552,281     $ 115,336
     =======================================================================================


F.   Federal Income Taxes

     It is the Fund's policy to comply with the requirements of the Internal
     Revenue Code applicable to regulated investment companies and to distribute
     all of its net taxable income and net realized capital gains, if any, to
     its shareowners. Therefore, no provision for federal income taxes is
     required. As of November 30, 2016, the Fund did not accrue any interest or
     penalties with respect to uncertain tax positions, which, if applicable,
     would be recorded as an income tax expense in the Statement of Operations.
     Tax returns filed within the prior three years are subject to examination
     by Federal and State tax authorities.

     In addition to meeting the requirements of the Internal Revenue Code, the
     Fund may be required to pay local taxes on the recognition of capital gains
     and/or the repatriation of foreign currencies in certain countries. During
     the six months ended May 31, 2017, the Fund paid no such taxes.

                  Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17 35


     In determining the daily net asset value, the Fund estimates the reserve
     for such taxes, if any, associated with investments in certain countries.
     The estimated reserve for the capital gains is based on the net unrealized
     appreciation on certain portfolio securities, the holding period of such
     securities and the related tax rates, tax loss carryforwards (if
     applicable) and other such factors. As of May 31, 2017, the Fund had no
     reserve related to capital gains.

     The amount and character of income and capital gain distributions to
     shareowners are determined in accordance with federal income tax rules,
     which may differ from U.S. GAAP. Distributions in excess of net investment
     income or net realized gains are temporary overdistributions for financial
     statement purposes resulting from differences in the recognition or
     classification of income or distributions for financial statement and tax
     purposes. Capital accounts within the financial statements are adjusted for
     permanent book/tax differences to reflect tax character, but are not
     adjusted for temporary differences.

     The tax character of current year distributions payable will be determined
     at the end of the current taxable year. The tax character of distributions
     during the year ended November 30, 2016 was as follows:



     --------------------------------------------------------------------------
                                                                           2016
     --------------------------------------------------------------------------
                                                                  
     Distribution paid from:
     Ordinary income                                                 $3,568,763
     Long-term capital gain                                                  --
     --------------------------------------------------------------------------
          Total                                                      $3,568,763
     ==========================================================================


     The following shows the components of distributable earnings on a federal
     income tax basis at November 30, 2016:



     --------------------------------------------------------------------------
                                                                           2016
     --------------------------------------------------------------------------
                                                               
     Distributable earnings:
     Capital loss carryforward                                    $(29,798,844)
     Current year late year currency loss                             (213,706)
     Net unrealized depreciation                                   (18,063,518)
     --------------------------------------------------------------------------
          Total                                                   $(48,076,068)
     ==========================================================================


     The difference between book-basis and tax-basis net unrealized depreciation
     is attributable to the tax deferral of losses on wash sales and the mark to
     market of forward currency contracts.

36 Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17


G.   Fund Shares

     The Fund records sales and repurchases of its shares as of trade date.
     Amundi Pioneer Distributor, Inc., formerly Pioneer Funds Distributor, Inc.
     (PFD), the principal underwriter for the Fund, earned $5,023 in
     underwriting commissions on the sale of Class A shares during the six
     months ended May 31, 2017.

H.   Class Allocations

     Income, common expenses and realized and unrealized gains and losses are
     calculated at the Fund level and allocated daily to each class of shares
     based on its respective percentage of adjusted net assets at the beginning
     of the day.

     Distribution fees are calculated based on the average daily net asset value
     attributable to Class A, Class C and Class R shares of the Fund,
     respectively (see Note 4). Class Y shares do not pay distribution fees. All
     expenses and fees paid to the Fund's transfer agent for its services are
     allocated among the classes of shares based on the number of accounts in
     each class and the ratable allocation of related out-of-pocket expenses
     (see Note 3).

     Distributions to shareowners are recorded as of the ex-dividend date.
     Distributions paid by the Fund with respect to each class of shares are
     calculated in the same manner and at the same time except that net
     investment income dividends to Class A, Class C, Class R and Class Y shares
     can reflect different transfer agent and distribution expense rates.

I.   Risks

     The value 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 rates, lack of liquidity in the bond markets or adverse
     investor sentiment. In the past several years, financial markets have
     experienced increased volatility, depressed valuations, decreased liquidity
     and heightened uncertainty. These conditions may continue, recur, worsen or
     spread.

     The Fund's investments in emerging markets or countries with limited or
     developing markets may subject the Fund to a greater degree of risk than
     investments in a developed market. Risks associated with these developing
     markets include political, social and economic factors and may affect the
     price of the Fund's investments and income generated by these investments,
     as well as the Fund's ability to repatriate such amounts. At times, the
     Fund's investments may represent industries or industry sectors that are
     interrelated or have common risks, making the Fund more susceptible to any
     economic, political or regulatory developments or other risks affecting
     those industries

                  Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17 37


     and sectors. The Fund's prospectus contains unaudited information regarding
     the Fund's principal risks. Please refer to that document when considering
     the Fund's principal risks.

2. Management Agreement

Amundi Pioneer, formerly PIM, manages the Fund's portfolio. Management fees are
calculated daily at an annual rate equal to 1.10% of the Fund's average daily
net assets up to $1 billion and 1.05% on assets over $1 billion. For the six
months ended May 31, 2017, the effective management fee (excluding waivers
and/or assumption of expenses) was 1.10% of the Fund's average daily net assets.

Amundi Pioneer, formerly PIM, has contractually agreed to limit ordinary
operating expenses to the extent required to reduce Fund expenses to 1.95%,
2.85% and 2.20% of the average daily net assets attributable to Class A, Class C
and Class R shares, respectively. These expense limitations are in effect
through April 1, 2018. There can be no assurance that Amundi Pioneer, formerly
PIM, will extend the expense limitation agreement for a class of shares beyond
the date referred to above. Fees waived and expenses reimbursed during the six
months ended May 31, 2017 are reflected on the Statement of Operations. Class Y
shares do not have an expense limitation.

In addition, under the management and administration agreements, certain other
services and costs, including accounting, regulatory reporting and insurance
premiums, are paid by the Fund as administrative reimbursements. Included in
"Due to affiliates" reflected on the Statement of Assets and Liabilities is
$124,538 in management fees, administrative costs and certain other
reimbursements payable to Amundi Pioneer, formerly PIM, at May 31, 2017.

3. Transfer Agent

Boston Financial Data Services, Inc. serves as the transfer agent to the Fund at
negotiated rates. Transfer agent fees and payables shown on the Statement of
Operations and the Statement of Assets and Liabilities, respectively, include
sub-transfer agent expenses incurred through the Fund's omnibus relationship
contracts.

In addition, the Fund reimbursed the transfer agent for out-of-pocket expenses
incurred by the transfer agent related to shareholder communications activities
such as proxy and statement mailings and outgoing phone calls. For the six
months ended May 31, 2017, such out-of-pocket expenses by class of shares were
as follows:

38 Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17




--------------------------------------------------------------------------------
Shareholder Communications:
--------------------------------------------------------------------------------
                                                                      
Class A                                                                  $33,572
Class C                                                                    5,076
Class R                                                                      728
Class Y                                                                      347
--------------------------------------------------------------------------------
  Total                                                                  $39,723
================================================================================


4. Distribution and Service Plans

The Fund has adopted a Distribution Plan (the Plan) pursuant to Rule 12b-1 of
the Investment Company Act of 1940 with respect to its Class A, Class C and
Class R shares. Pursuant to the Plan, the Fund pays Amundi Pioneer Distributor,
Inc., formerly PFD, 0.25% of the average daily net assets attributable to Class
A shares as compensation for personal services and/or account maintenance
services or distribution services with regard to Class A shares. Pursuant to the
Plan, the Fund also pays Amundi Pioneer Distributor, Inc., formerly PFD, 1.00%
of the average daily net assets attributable to Class C shares. The fee for
Class C shares consists of a 0.25% service fee and a 0.75% distribution fee paid
as compensation for personal services and/or account maintenance services or
distribution services with regard to Class C shares. Pursuant to the Plan, the
Fund further pays Amundi Pioneer Distributor, Inc., formerly PFD, 0.50% of the
average daily net assets attributable to Class R shares for distribution
services. Included in "Due to affiliates" reflected on the Statement of Assets
and Liabilities is $41,124 in distribution fees payable to Amundi Pioneer
Distributor, Inc., formerly PFD, at May 31, 2017.

The Fund also has adopted a separate service plan for Class R shares (Service
Plan). The Service Plan authorizes the Fund to pay securities dealers, plan
administrators or other service organizations that agree to provide certain
services to retirement plans or plan participants holding shares of the Fund a
service fee of up to 0.25% of the Fund's average daily net assets attributable
to Class R shares held by such plans.

In addition, redemptions of each class of shares (except Class R and Class Y
shares) may be subject to a contingent deferred sales charge (CDSC). A CDSC of
1.00% may be imposed on redemptions of certain net asset value purchases of
Class A shares within 12 months of purchase. Redemptions of Class C shares
within 12 months of purchase are subject to a CDSC of 1.00%, based on the lower
of cost or market value of shares being redeemed. Shares purchased as part of an
exchange remain subject to any CDSC that applied to the original purchase of
those shares. There is no CDSC for Class R or Class Y shares. Proceeds from the
CDSCs are paid to Amundi Pioneer Distributor, Inc., formerly PFD. For the six
months ended May 31, 2017, CDSCs in the amount of $11,636 were paid to Amundi
Pioneer Distributor, Inc., formerly PFD.

                  Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17 39


5. Forward Foreign Currency Contracts

At May 31, 2017, the Fund had entered into various forward foreign currency
contracts that obligate the Fund to deliver or take delivery of currencies at
specified future maturity dates. Alternatively, prior to the settlement date of
a forward foreign currency contract, the Fund may close out such contract by
entering into an offsetting contract. The average value of forward foreign
currency contracts open during the six months ended May 31, 2017 was $3,540,748.
Open forward foreign currency contracts at May 31, 2017 were as follows:



----------------------------------------------------------------------------------------------------------
                                         In
 Currency                    Currency    Exchange                                Settlement   Unrealized
 Sold        Deliver         Purchased   for              Counterparty           Date         Appreciation
----------------------------------------------------------------------------------------------------------
                                                                            
 USD           (1,488,877)   KRW         1,700,000,000    Deutsche Bank AG       7/13/2017    $  31,317
 USD           (3,737,092)   TWD           114,000,000    Morgan Stanley Co.     7/13/2017       50,550
 USD             (589,001)   MXN            11,192,288    Goldman Sachs & Co.    7/13/2017        6,844
 USD           (3,390,343)   ZAR            48,018,757    Goldman Sachs & Co.    7/13/2017      240,153
 USD           (3,175,334)   INR           207,000,000    Deutsche Bank AG       7/13/2017       16,229
 USD           (1,793,923)   MYR             8,000,000    Goldman Sachs & Co.    7/13/2017       71,037
 NGN         (712,500,000)   USD             2,165,654    Barclays Bank Plc      7/13/2017       10,199
----------------------------------------------------------------------------------------------------------
 Total                                                                                        $ 426,329
==========================================================================================================




----------------------------------------------------------------------------------------------------------
                                         In
 Currency                    Currency    Exchange                                Settlement   Unrealized
 Sold        Deliver         Purchased   for                Counterparty         Date         Depreciation
----------------------------------------------------------------------------------------------------------
                                                                            
 BRL         (33,000,000)    USD             10,097,909     Morgan Stanley Co.   7/13/2017    $ (3,796)
 NGN        (903,000,000)    USD              2,699,153     Morgan Stanley Co.   7/13/2017     (32,602)
 NGN        (284,500,000)    USD                849,254     Deutsche Bank AG     7/13/2017     (11,416)
 USD          (1,704,163)    IDR         22,800,000,000     Morgan Stanley Co    7/13/2017        (866)
----------------------------------------------------------------------------------------------------------
 Total                                                                                        $(48,680)
==========================================================================================================


     BRL - Brazilian Real          MYR - Malaysian Ringgit
     IDR - Indonesian Rupiah       NGN - Nigerian Naira
     INR - Indian Rupee            TWD - New Taiwan Dollar
     KRW - South Korean Won        ZAR - South African Rand
     MXN - Mexican Peso

6. Line of Credit Facility

The Fund, along with certain other funds in the Pioneer Family of Funds (the
Funds), participates in a committed, unsecured revolving line of credit
facility. Borrowings are used solely for temporary or emergency purposes. The
Fund may borrow up to the lesser of the amount available under the facility or
the limits set for borrowing by the Fund's prospectus and the 1940 Act. The
credit facility in which the Fund participated until February 9, 2016 was in the
amount of $240 million. The credit facility in which the Fund participated until
February 7, 2017, was in the amount of $220 million. Effective February 8, 2017,
the Fund participates in a facility that is in the amount of

40 Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17


$49 million. Under such facility, depending on the type of loan, interest on
borrowings is payable at the London Interbank Offered Rate (LIBOR) plus 0.85% on
an annualized basis, or the Alternate Base Rate, which is the greater of (a) the
facility's administrative agent's daily announced prime rate on the borrowing
date, (b) 2% plus the Federal Funds Rate on the borrowing date or (c) 2% plus
the overnight Eurodollar rate on the borrowing date. The Funds pay an annual
commitment fee to participate in a credit facility. The commitment fee is
allocated among participating Funds based on an allocation schedule set forth in
the credit agreement. For the six months ended May 31, 2017, the Fund had no
borrowings under the credit facility.

7. Assets and Liabilities Offsetting

The Fund has entered into an International Swaps and Derivatives Association,
Inc. Master Agreement ("ISDA Master Agreement") or similar agreement with
substantially all its derivative counterparties. An ISDA Master Agreement is a
bilateral agreement between the Fund and a counterparty that governs the trading
of certain OTC derivatives and typically contains, among other things, close-out
and set-off provisions which apply upon the occurrence of an event of default
and/or a termination event as defined under the relevant ISDA Master Agreement.
The ISDA Master Agreement may also give a party the right to terminate all
transactions traded under such agreement if, among other things, there is
deterioration in the credit quality of the other party. Upon an event of default
or a termination of the ISDA Master Agreement, the non-defaulting party has the
right to close out all transactions under such agreement and to net amounts owed
under each transaction to determine one net amount payable by one party to the
other. The right to close out and net payments across all transactions under the
ISDA Master Agreement could result in a reduction of the Fund's credit risk to
its counterparty equal to any amounts payable by the Fund under the applicable
transactions, if any. However, the Fund's right to setoff may be restricted or
prohibited by the bankruptcy or insolvency laws of the particular jurisdiction
to which each specific ISDA of each counterparty is subject.

The collateral requirements for derivatives transactions under an ISDA Master
Agreement are governed by a credit support annex to the ISDA Master Agreement.
Collateral requirements are generally determined at the close of business each
day and are typically based on changes in market values for each transaction
under an ISDA Master Agreement and netted into one amount for such agreement.
Generally, the amount of collateral due from or to a counterparty is subject to
threshold (a "minimum transfer amount") before a transfer is required, which may
vary by counterparty. Collateral pledged for the benefit of the Fund and/or
counterparty is held in segregated accounts by the Fund's custodian and cannot
be sold, re-pledged, assigned or otherwise used while pledged. Cash that has
been segregated to cover the Fund's

                  Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17 41


collateral obligations, if any, will be reported separately in the Statement of
Assets and Liabilities as "Restricted Cash." Securities pledged by the Fund as
collateral, if any, are identified as such in the Schedule of Investments.

Financial instruments subject to an enforceable master netting agreement such as
an ISDA Master Agreement have not been offset on the Statement of Assets and
Liabilities. The following charts show gross assets and liabilities of the Fund
as of May 31, 2017.



-------------------------------------------------------------------------------------------------------
                        Derivative
                        Assets
                        Subject to       Derivatives    Non-Cash        Cash           Net Amount
                        Master Netting   Available      Collateral      Collateral     of Derivative
 Counterparty           Agreement        for Offset     Received (a)    Received (a)   Assets (b)
-------------------------------------------------------------------------------------------------------
                                                                        
 Barclays Bank Plc      $    10,199      $         --   $  --           $  --          $ 10,199
 Deutsche Bank AG            47,546           (11,416)     --              --            36,130
 Goldman
  Sachs & Co.               318,034                --      --              --           318,034
 Morgan Stanley Co.          50,550           (37,264)     --              --            13,286
-------------------------------------------------------------------------------------------------------
 Total                  $   426,329      $    (48,680)  $  --           $  --          $377,649
=======================================================================================================




-------------------------------------------------------------------------------------------------------
                        Derivative
                        Liabilities
                        Subject to       Derivatives    Non-Cash        Cash           Net Amount
                        Master Netting   Available      Collateral      Collateral     of Derivative
 Counterparty           Agreement        for Offset     Pledged (a)     Pledged (a)    Liabilities (c)
-------------------------------------------------------------------------------------------------------
                                                                        
 Barclays Bank Plc      $        --      $         --   $  --           $  --          $     --
 Deutsche Bank AG                --                --      --              --                --
 Goldman
  Sachs & Co.                    --                --      --              --                --
 Morgan Stanley Co.          37,264           (37,264)     --              --                --
-------------------------------------------------------------------------------------------------------
 Total                  $    37,264      $    (37,264)  $  --           $  --          $     --
=======================================================================================================


(a)  The amount presented here may be less than the total amount of collateral
     received/pledged as the net amount of derivative assets and liabilities
     cannot be less than $0.

(b)  Represents the net amount due from the counterparty in the event of
     default.

(c)  Represents the net amount payable to the counterparty in the event of
     default.

8. Additional Disclosures about Derivative Instruments and Hedging
   Activities

The Fund's use of derivatives may subject it to the following risks:

Interest rate risk relates to the fluctuations in the value of interest-bearing
securities due to changes in the prevailing levels of market interest rates.

Credit risk relates to the ability of the issuer of a financial instrument to
make further principal or interest payments on an obligation or commitment that
it has to the Fund.

42 Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17


Foreign exchange rate risk relates to fluctuations in the value of an asset or
liability due to changes in currency exchange rates.

Equity risk relates to the fluctuations in the value of financial instruments as
a result of changes in market prices (other than those arising from interest
rate risk or foreign exchange risk), whether caused by factors specific to an
individual investment, its issuer, or all factors affecting all instruments
traded in a market or market segment.

Commodity risk relates to the risk that the value of a commodity or commodity
index will fluctuate based on increases or decreases in the commodities market
and factors specific to a particular industry or commodity.

The fair value of open derivative instruments (not considered to be hedging
instruments for accounting disclosure purposes) by risk exposure at May 31, 2017
was as follows:




------------------------------------------------------------------------------------------------------
Statement of Assets and Liabilities
                                                        Foreign
                          Interest       Credit         Exchange           Equity         Commodity
                          Rate Risk      Risk           Rate Risk          Risk           Risk
------------------------------------------------------------------------------------------------------
                                                                           
Assets
 Unrealized appreciation
  of forward foreign
  currency contracts      $  --          $  --          $426,329           $     --       $  --
 Unrealized
  appreciation of
  futures contracts*         --             --                --            279,343          --
------------------------------------------------------------------------------------------------------
Total Value               $  --          $  --          $426,329           $279,343       $  --
======================================================================================================
Liabilities
 Unrealized depreciation
   of forward foreign
   currency contracts     $  --          $  --          $ 48,680           $     --       $  --
 Unrealized
   depreciation of
   futures contracts*        --             --                --            164,007          --
------------------------------------------------------------------------------------------------------
Total Value               $  --          $  --          $ 48,680           $164,007       $  --
======================================================================================================


*    Reflects unrealized appreciation/depreciation of futures contracts (see
     Note 1E). The current day's variation margin is disclosed on the Statement
     of Assets and Liabilities.

                  Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17 43


The effect of derivative instruments (not considered to be hedging instruments
for accounting disclosure purposes) on the Statement of Operations by risk
exposure at May 31, 2017 was as follows:



---------------------------------------------------------------------------------------------
Statement of Operations
                            Foreign
                            Interest    Credit      Exchange          Equity        Commodity
                            Rate Risk   Risk        Rate Risk         Risk          Risk
---------------------------------------------------------------------------------------------
                                                                     
Net realized gain
 (loss) on
 Futures contracts          $    --     $    --     $          --     $ 274,966     $    --
 Forward foreign
   currency contracts*           --          --        (1,228,179)           --          --
---------------------------------------------------------------------------------------------
Total Value                 $    --     $    --     $  (1,228,179)    $ 274,966     $    --
=============================================================================================
  Change in net
   unrealized
   appreciation
  (depreciation) on
  Futures contracts         $    --     $    --     $          --     $ 110,653     $    --
  Forward foreign
    currency contracts* --                   --           935,484            --          --
---------------------------------------------------------------------------------------------
Total Value                 $    --     $    --     $     935,484     $ 110,653     $    --
=============================================================================================


*    Included in the amount shown on the Statement of Operations as forward
     foreign currency contracts and other assets and liabilities denominated in
     foreign currencies.

44 Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17


ADDITIONAL INFORMATION

Change in Independent Registered Public Accounting Firm

Prior to July 3, 2017 Pioneer Investment Management, Inc. (the "Adviser"), the
Fund's investment adviser, was an indirect, wholly owned subsidiary of UniCredit
S.p.A. ("UniCredit"). On that date, UniCredit completed the sale of its Pioneer
Investments business, which includes the Adviser, to Amundi (the "Transaction").
As a result of the Transaction, the Adviser became an indirect, wholly-owned
subsidiary of Amundi. Amundi is controlled by Credit Agricole S.A. Amundi is
headquartered in Paris, France, and, as of September 30, 2016, had more than
$1.1 trillion in assets under management worldwide.

Deloitte & Touche LLP ("D&T"), the Fund's previous independent registered public
accounting firm, informed the Audit Committee and the Board that it would no
longer be independent with respect to the Fund upon the completion of the
Transaction as a result of certain services being provided to Amundi and Credit
Agricole, and, accordingly, that it intended to resign as the Fund's independent
registered public accounting firm upon the completion of the Transaction. D&T's
resignation was effective on July 3, 2017, when the Transaction was completed.

During the periods as to which D&T has served as the Fund's independent
registered public accounting firm, including the Fund's two most recent fiscal
years preceding the fiscal year ended June 30, 2017, D&T's reports on the Fund's
financial statements have not contained an adverse opinion or disclaimer of
opinion and have not been qualified or modified as to uncertainty, audit scope
or accounting principles. Further, there have been no disagreements with D&T on
any matter of accounting principles or practices, financial statement
disclosure, or auditing scope or procedure, which, if not resolved to the
satisfaction of D&T, would have caused D&T to make reference to the subject
matter of the disagreement in connection with its report on the financial
statements. In addition, there have been no reportable events of the kind
described in Item 304(a)(1)(v) of Regulation S-K under the Securities Exchange
Act of 1934.

Effective immediately following the completion of the Transaction on July 3,
2017, the Board, acting upon the recommendation of the Audit Committee, engaged
a new independent registered public accounting firm, Ernst & Young LLP ("EY"),
for the Fund's fiscal year ended June 30, 2017.

                  Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17 45


Prior to its engagement, EY had advised the Fund's Audit Committee that EY had
identified the following matters, in each case relating to services rendered by
other member firms of Ernst & Young Global Limited, all of which are located
outside the United States, to UniCredit and certain of its subsidiaries during
the period commencing July 1, 2016, that it determined to be inconsistent with
the auditor independence rules set forth by the Securities and Exchange
Commission ("SEC"): (a) project management support services to UniCredit in the
Czech Republic, Germany, Italy, Serbia and Slovenia in relation to twenty-two
projects, that were determined to be inconsistent with Rule 2-01(c)(4)(vi) of
Regulation S-X (management functions); (b) two engagements for UniCredit in
Italy where fees were contingent/success based and that were determined to be
inconsistent with Rule 2-01(c)(5) of Regulation S-X (contingent fees); (c) four
engagements where legal and expert services were provided to UniCredit in the
Czech Republic and Germany, and twenty engagements where the legal advisory
services were provided to UniCredit in Austria, Czech Republic, Italy and
Poland, that were determined to be inconsistent with Rule 2-01(c)(4)(ix) and (x)
of Regulation S-X (legal and expert services); and (d) two engagements for
UniCredit in Italy involving assistance in the sale of certain assets, that were
determined to be inconsistent with Rule 2-01(c)(4)(viii) of Regulation S-X
(broker-dealer, investment advisor or investment banking services). None of the
foregoing services involved the Fund, any of the other funds in the Pioneer
Family of Funds or any other Pioneer entity sold by UniCredit in the
Transaction.

EY advised the Audit Committee that it had considered the matters described
above and had concluded that such matters would not impair EY's ability to
exercise objective and impartial judgment in connection with the audits of the
financial statements of the Fund under the SEC and Public Company Accounting
Oversight Board independence rules, and that a reasonable investor with
knowledge of all relevant facts and circumstances would reach the same
conclusion. Management and the Audit Committee considered these matters and
discussed the matters with EY and, based upon EY's description of the matters
and statements made by EY, Management and the Audit Committee believe that EY
will be capable of exercising objective and impartial judgment in connection
with the audits of the financial statements of the Fund, and Management further
believes that a reasonable investor with knowledge of all relevant facts and
circumstances would reach the same conclusion.

Reorganization

In July 2017, the Board of Trustees of the Pioneer Funds approved the
reorganization of Pioneer Emerging Markets Fund into Pioneer Global Equity Fund.
The combined fund will be renamed Pioneer Global Equity Fund. The reorganization
is expected to be completed during the fourth calendar quarter of 2017.

46 Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17


Approval of New and Interim Management Agreements

Amundi Pioneer Asset Management, Inc. (Amundi Pioneer), formerly Pioneer
Investment Management, Inc., serves as the investment adviser to Pioneer
Emerging Markets Fund (the Fund) pursuant to an investment management agreement
between Amundi Pioneer and the Fund.

On July 3, 2017, Amundi acquired Pioneer Investments, a group of asset
management companies located throughout the world (the "Transaction"). As a
result of the Transaction, Amundi Pioneer became an indirect wholly-owned
subsidiary of Amundi and Amundi's wholly-owned subsidiary, Amundi USA, Inc.
Prior to July 3, 2017, Pioneer Investments was owned by Pioneer Global Asset
Management S.p.A. ("PGAM"), a wholly-owned subsidiary of UniCredit S.p.A.
("UniCredit").

Under the Investment Company Act of 1940, the Fund's current investment
management agreement (the "Current Management Agreement") terminated
automatically upon the consummation of the Transaction. In order for Amundi
Pioneer to continue to manage the Fund after the consummation of the
Transaction, the Trustees and shareholders of the Fund were required to approve
a new investment management agreement for the Fund (the "New Management
Agreement"). As discussed below, the Board of Trustees of the Fund approved the
New Management Agreement at a meeting held on March 6-7, 2017. The New
Management Agreement was approved by the shareholders of the Fund at a meeting
held on June 13, 2017. The Board of Trustees of the Fund also approved an
interim investment management agreement between Amundi Pioneer and the Fund (the
"Interim Management Agreement") at the March 6-7, 2017 meeting. The Interim
Management Agreement would have taken effect upon the closing of the Transaction
in the event that the shareholders of the Fund did not approve the New
Management Agreement.

Board Evaluation of the New and Interim Management Agreements

The Board evaluated the Transaction and the New Management Agreement and Interim
Management Agreement for the Fund. In connection with their evaluation of the
Transaction and the New Management Agreement for the Fund, the Trustees
requested such information as they deemed reasonably necessary, including: (a)
the structure of the Transaction and the strategy underlying the Transaction;
(b) the anticipated benefits of the Transaction to the Fund and its
shareholders; (c) the post-Transaction plans for Amundi Pioneer, including
Amundi's plans for integration of Pioneer Investments and Amundi Pioneer with
its existing asset management businesses and plans for the future development of
Amundi Pioneer; (d) the effect of the Transaction

                  Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17 47


on the ongoing services provided to the Fund, including the need to select a new
independent registered public accounting firm for the Fund, and any plans to
modify the operations of the Fund; (e) the stability and continuity of Amundi
Pioneer's management and key employees, including compensation and benefits to
Amundi Pioneer's key employees, and retention plans and incentive plan
structure; (f) the post-Transaction indebtedness and financial resources of
Amundi Pioneer; (g) Amundi's legal and operational structure, its principal
shareholders and senior management, its investment management, risk management,
administrative, legal and compliance functions; (h) certain regulatory matters
relating to Amundi's affiliates; and (i) Amundi's commitment to the United
States, including the role of Amundi Pioneer in the larger Amundi business.

The Trustees also requested and obtained the following information in connection
with their evaluation of the Transaction and the New Management Agreement for
the Fund: (i) memoranda provided by Fund counsel that summarized the legal
standards and other considerations that are relevant to the Trustees in their
deliberations regarding the New Management Agreement; (ii) the qualifications of
the investment management teams for the Fund, as well as the level of investment
by the Fund's portfolio managers in the Fund; (iii) the Fund's management fees
and total expense ratios, the financial statements of Amundi Pioneer and its
pre- and post-Transaction parent companies, profitability analyses from Amundi
Pioneer, and analyses from Amundi Pioneer as to possible economies of scale;
(iv) the profitability of the institutional business of Amundi Pioneer and
Amundi Pioneer's affiliate, Amundi Pioneer Institutional Asset Management, Inc.
("Amundi Pioneer Institutional") as compared to that of Amundi Pioneer's fund
management business; and (v) the differences between the fees and expenses of
the Fund and the fees and expenses of Amundi Pioneer's and Amundi Pioneer
Institutional's institutional accounts, as well as the different services
provided by Adviser to the Fund and by Amundi Pioneer and Amundi Pioneer
Institutional to the institutional accounts. In addition, the Trustees
considered the information provided at regularly scheduled meetings throughout
the year regarding the Fund's performance and risk attributes, including through
meetings with investment management personnel, and took into account other
information related to the Fund provided to the Trustees at regularly scheduled
meetings. The Trustees also considered information they had received in their
review of the continuance of the Current Management Agreement for the Fund in
September 2016.

At meetings held on January 9, 2017 and January 10, 2017, the Trustees met with
representatives of Amundi and PGAM, including separate meetings of the Trustees
who are not "interested persons" of the Fund Complex ("Independent Trustees")
and counsel with representatives of Amundi and

48 Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17


PGAM, and subsequently with representatives of Amundi. In those meetings, they
received an extensive presentation from the representatives of Amundi, including
the chief executive officer of Amundi, describing Amundi's background and
history, its global asset management activities, the growth of its business, and
its status as the largest asset management firm in Europe and one of the largest
globally; its capital structure and financial resources, including information
as to the financing of the Transaction; its principal investors, including its
majority investor Credit Agricole S.A., and Credit Agricole's long-term
commitment to the asset management business; the philosophy and strategy
underlying the Transaction and the complementarity of Amundi's and Pioneer
Investments' respective asset management businesses; Amundi's various operating
and investment committees and how they would likely interact with Amundi
Pioneer; the proposed integration process, including the progress to date and
the establishment of various integration work streams; Amundi's plans for
management of Amundi Pioneer; Amundi's philosophy as to compensation of key
employees and its general intentions with respect to incentive plans for key
employees of Amundi Pioneer; Amundi's preliminary plans to achieve cost and
other synergies; and opportunities to further develop the business of Amundi
Pioneer and Amundi Pioneer Institutional, including in the area of institutional
asset management, and how that would benefit shareholders of the Pioneer Funds.

In those meetings, the representatives of Amundi confirmed their intention that
the Chief Executive Officer and Chief Investment Officer of Amundi Pioneer would
remain in their current positions, and confirmed that they do not currently
foresee major changes in the day-to-day investment management operations of
Amundi Pioneer with respect to the Fund as a direct result of the Transaction.
They discussed incentive arrangements for key personnel that would continue
after the closing of the Transaction and their plans to establish a new
long-term incentive plan following the closing. They also generally discussed
ways in which Amundi Pioneer could potentially draw on the expanded global
resources of Amundi post-Transaction. At those meetings, the Independent
Trustees identified certain areas to which they requested further information,
including as to trading and execution of securities transactions, research and
portfolio management and potential changes in investment process, particularly
where asset classes managed by Amundi Pioneer would overlap with asset classes
managed by Amundi, the continued availability of resources currently at Pioneer
Investments or elsewhere within Amundi to assist in management of certain Funds,
and any anticipated significant changes in operations. The Independent Trustees
considered the uncertainty as to whether the Fund's independent registered
public accounting

                  Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17 49


firm could continue to act in that capacity after the closing of the
Transaction. The Independent Trustees also met with counsel to review the
information they had received to date and to discuss next steps.

Subsequently, the Trustees received further information from Amundi, including
written responses to questions raised by the Independent Trustees, and received
from Amundi Pioneer the information requested of it. The Independent Trustees
reviewed the information provided with counsel at telephonic meetings held on
February 16, 2017 and February 27, 2017. The Trustees held a special in-person
Board meeting on March 6-7, 2017 for further consideration of the New Management
Agreements, the Interim Management Agreements and the Transaction. The Trustees
met again with senior executives of Amundi at the March 6-7, 2017 meeting.

At the March 6-7, 2017 meeting, based on their evaluation of the information
provided by Amundi Pioneer and Amundi, the Trustees including the Independent
Trustees voting separately, approved the New Management Agreement and the
Interim Management Agreement for the Fund. In considering the New Management
Agreement for the Fund, the Trustees considered various factors that they
determined were relevant, including the factors described below. The Trustees
did not identify any single factor as the controlling factor in their
determinations. The Trustees considered the same factors with respect to the
Interim Management Agreement for the Fund.

Nature, Extent and Quality of Services

The Trustees considered the nature, extent and quality of the services that had
been provided by Amundi Pioneer to the Fund and that are expected to be provided
by Amundi Pioneer to the Fund following the consummation of the Transaction. The
Trustees reviewed the terms of the New Management Agreement, and noted that such
terms are substantially similar to the terms of the Current Management
Agreement, except for different execution dates, effective dates and termination
dates. The Trustees reviewed Amundi Pioneer's investment approach for the Fund
and its research process. The Trustees considered the resources of Amundi
Pioneer and the personnel of Amundi Pioneer who provide investment management
services to the Fund. They also reviewed the amount of non-investment resources
and personnel of Amundi Pioneer that are involved in Amundi Pioneer's services
to the Fund, including Amundi Pioneer's compliance and legal resources and
personnel. The Trustees noted the substantial attention and high priority given
by Amundi Pioneer's senior management to the Pioneer Fund complex.

The Trustees considered that Amundi Pioneer supervises and monitors the
performance of the Fund's service providers and provides the Fund with personnel
(including Fund officers) and other resources that are necessary for

50 Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17


the Fund's business management and operations and that Amundi Pioneer would
continue to provide those investment management and research services and
resources to the Fund following the consummation of the Transaction. The
Trustees also considered that, as administrator, Amundi Pioneer would continue
to be responsible for the administration of the Fund's business and other
affairs. The Trustees considered the fees to be paid to Amundi Pioneer for the
provision of administration services.

The Trustees considered that Deloitte & Touche LLP informed the Board that it
would no longer be independent with respect to the Fund upon the completion of
the Transaction and, accordingly, that it would be necessary for the Board to
engage a new independent registered public accounting firm for the Fund.

The Trustees considered that the Transaction was not expected to have a material
adverse impact on the nature, scope and overall quality of services provided to
the Fund and its shareholders, including investment management, risk management,
administrative, compliance, legal and other services, as a result of the
Transaction.

In that regard, the Trustees considered that Amundi is one of the largest asset
managers globally, and that Amundi Pioneer may have access to additional
research and portfolio management capabilities as a result of the Transaction
and that Amundi Pioneer, as part of Amundi, is expected to have an enhanced
global presence that may contribute to an increase in the overall scale and
resources of Amundi Pioneer. Furthermore, in considering whether the Transaction
would be expected to have a material adverse impact on the nature, scope and
overall quality of services provided to the Fund and its shareholders, the
Trustees considered the statements by representatives of Amundi that they expect
the Chief Executive Officer and Chief Investment Officer of Amundi Pioneer to
remain in their current positions and that they do not currently foresee major
changes in the day-to-day investment management operations of Amundi Pioneer as
a direct result of the Transaction, or the risk management, legal or compliance
services provided by Amundi Pioneer, with respect to the Fund. They further
considered the current incentive arrangements for key personnel of Amundi
Pioneer that would continue after the closing of the Transaction They also noted
Amundi's stated intention to establish a new long-term incentive plan following
the closing.

The Trustees also took into account their experience in evaluating the proposed
combination of Pioneer Investments and Santander Asset Management, which was
announced in September, 2014 and abandoned in July, 2016. In light of, among
other things, this experience, the Trustees determined that they were not able
to identify any realistic alternatives to

                  Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17 51


approving the New Management Agreement that would provide the level of services
to the Fund and its shareholders that are expected to be provided by Amundi
Pioneer after the closing of the Transaction.

Based on these considerations, the Trustees concluded that the nature, extent
and quality of services that Amundi Pioneer would continue to provide to the
Fund under the New Management Agreement would be satisfactory and consistent
with the terms of the New Management Agreement.

Performance of the Fund

In considering the Fund's performance, the Trustees regularly reviewed and
discussed throughout the year data prepared by Amundi Pioneer and information
comparing the Fund's performance with the performance of its peer group of
funds, as classified by each of Morningstar, Inc. (Morningstar) and Lipper, and
the performance of the Fund's benchmark index. They also discussed the Fund's
performance with Amundi Pioneer on a regular basis.

The Trustees discussed the Fund's performance with Amundi Pioneer on a more
frequent basis in light of the Fund's unfavorable performance compared to its
benchmark index and peers over certain periods. The Trustees noted Amundi
Pioneer's explanation for the Fund's relative performance and the steps taken by
Amundi Pioneer to address the Fund's performance, including increasing the
diversification of the Fund's portfolio, investing in larger capitalization
companies and reducing the Fund's tracking error relative to its benchmark. It
also was noted that the Fund's recent performance was improved relative to its
peer group.

The Trustees' regular reviews and discussions, including the steps taken by
Amundi Pioneer to address the Fund's performance, were factored into the
Trustees' deliberations concerning the approval of the New Management Agreement.

Management Fee and Expenses

The Trustees noted that the stated management fees to be paid by the Fund are
identical under the Current Management Agreement and the New Management
Agreement. The Trustees considered information showing the fees and expenses of
the Fund in comparison to the management fees and expense ratios of its peer
group of funds as classified by Morningstar and also to the expense ratios of a
peer group of funds selected on the basis of criteria determined by the
Independent Trustees for this purpose using data provided by Strategic Insight
Mutual Fund Research and Consulting, LLC (Strategic Insight), an independent
third party. In all quintile rankings referred to below, first quintile is most
favorable to the Fund's shareowners. To the extent

52 Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17


applicable, the Trustees also considered the impact of transfer agency, sub-
transfer agency, and other non-management fee expenses on the expense
ratios of the Fund. The Trustees noted that they separately review the Fund's
transfer agency, sub-transfer agency and intermediary arrangements and that
the results of the most recent such review were considered in the consideration
of the Fund's expense ratio.

The Trustees considered that the Fund's management fee as of September 30, 2016
was in the fourth quintile relative to the management fees paid by other funds
in its Morningstar category for the comparable period. The Trustees considered
that the Fund's management fee was approximately four basis points higher than
the median management fee paid by other funds in its Morningstar category. The
Trustees also considered the breakpoint in the management fee schedule and the
reduced fee rate above a certain asset level. The Trustees considered that the
expense ratio of the Fund's Class A shares as of September 30, 2016 was in the
fifth quintile relative to its Morningstar category and in the fifth quintile
relative to its Strategic Insight peer group, in each case for the comparable
period. The Trustees noted that Amundi Pioneer had agreed to waive fees and/or
reimburse expenses in order to limit the ordinary operating expenses of the
Fund. The Trustees noted the impact of expenses relating to small accounts and
omnibus accounts on transfer and sub-transfer agency expenses generally.

The Trustees reviewed management fees charged by Amundi Pioneer and Amundi
Pioneer Institutional to institutional and other clients, including publicly
offered European funds sponsored by Amundi Pioneer's affiliates, unaffiliated
U.S. registered investment companies (in a sub-advisory capacity), and
unaffiliated foreign and domestic separate accounts. The Trustees also
considered Amundi Pioneer's costs in providing services to the Fund and Amundi
Pioneer's and Amundi Pioneer Institutional's costs in providing services to the
other clients and considered the differences in management fees and profit
margins for fund and non-fund services. In evaluating the fees associated with
Amundi Pioneer's and Amundi Pioneer Institutional's client accounts, the
Trustees took into account the respective demands, resources and complexity
associated with the Fund and other client accounts. The Trustees noted that in
some instances the fee rates for those clients were lower than the management
fee for the Fund and considered that, under both the Current Management
Agreement and the New Management Agreement, Amundi Pioneer would perform
additional services for the Fund that it does not provide to those other clients
or services that are broader in scope, including oversight of the Fund's other
service providers and activities related to compliance and the extensive
regulatory and tax regimes to which the Fund

                  Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17 53


is subject. The Trustees also considered the different risks associated with
Amundi Pioneer's management of the Fund and Amundi Pioneer's and Amundi Pioneer
Institutional's management of the other client accounts.

The Trustees concluded that the management fee payable by the Fund to Amundi
Pioneer was reasonable in relation to the nature and quality of the services to
be provided by Amundi Pioneer.

Profitability

The Trustees considered information provided by Amundi Pioneer regarding the
profitability of Amundi Pioneer with respect to the advisory services provided
by Amundi Pioneer to the Fund, including the methodology used by Amundi Pioneer
in allocating certain of its costs to the management of the Fund. The Trustees
also considered Amundi Pioneer's profit margin in connection with the overall
operation of the Fund. They further reviewed the financial results, including
the profit margins, realized by Amundi Pioneer and Amundi Pioneer Institutional
from non-fund businesses. The Trustees considered Amundi Pioneer's profit
margins with respect to the Fund in comparison to the limited industry data
available and noted that the profitability of any adviser was affected by
numerous factors, including its organizational structure and method for
allocating expenses. The Trustees concluded that Amundi Pioneer's profitability
with respect to the management of the Fund was not unreasonable.

Economies of Scale

The Trustees considered Amundi Pioneer's views relating to economies of scale in
connection with the Pioneer Funds as fund assets grow and the extent to which
any such economies of scale are shared with the Fund and Fund shareholders. The
Trustees recognize that economies of scale are difficult to identify and
quantify, and that, among other factors that may be relevant, are the following:
fee levels, expense subsidization, investment by Amundi Pioneer in research and
analytical capabilities and Amundi Pioneer's commitment and resource allocation
to the Fund. The Trustees noted that profitability also may be an indicator of
the availability of any economies of scale, although profitability may vary for
other reasons including due to reductions in expenses. The Trustees concluded
that economies of scale, if any, were being appropriately shared with the Fund.

Other Benefits

The Trustees considered the other benefits that Amundi Pioneer enjoys from its
relationship with the Fund. The Trustees considered the character and amount of
fees paid or to be paid by the Fund, other than under the Current Management
Agreement or the New Management Agreement, for services provided by Amundi
Pioneer and its affiliates. The Trustees further considered

54 Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17


the revenues and profitability of Amundi Pioneer's businesses other than the
Fund business. To the extent applicable, the Trustees also considered the
benefits to the Fund and to Amundi Pioneer and its affiliates from the use of
"soft" commission dollars generated by the Fund to pay for research and
brokerage services.

The Trustees considered that following the completion of the Transaction, Amundi
Pioneer will be the principal U.S. asset management business of Amundi, and that
Amundi's worldwide asset management business will manage over $1.38 trillion in
assets (including the Pioneer Funds). This may create opportunities for Amundi
Pioneer, Amundi Pioneer Institutional and Amundi that derive from Amundi
Pioneer's relationships with the Fund, including Amundi's ability to market the
services of Amundi Pioneer globally. The Trustees noted that Amundi Pioneer may
have access to additional research capabilities as a result of the Transaction
and Amundi's enhanced global presence that may contribute to an increase of the
overall scale of Amundi Pioneer. The Trustees considered that Amundi Pioneer and
the Fund are expected to receive reciprocal intangible benefits from the
relationship, including mutual brand recognition and, for the Fund, direct and
indirect access to the resources of a large global asset manager. The Trustees
concluded that any such benefits received by Amundi Pioneer as a result of its
relationship with the Fund were reasonable.

Conclusion

After consideration of the factors described above as well as other factors, the
Trustees, including the Independent Trustees, concluded that the New Management
Agreement and the Interim Management Agreement for the Fund, including the fees
payable thereunder, were fair and reasonable and voted to approve the New
Management Agreement and the Interim Management Agreement, and to recommend that
shareholders approve the New Management Agreement.

                  Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17 55

                          This page is for your notes.

56 Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17


                          This page is for your notes.

                  Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17 57

                          This page is for your notes.

58 Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17


                        This page is for your notes.

                  Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17 59


Trustees, Officers and Service Providers

Trustees                                    Officers
Thomas J. Perna, Chairman                   Lisa M. Jones, President and Chief
David R. Bock                                 Executive Officer
Benjamin M. Friedman                        Mark E. Bradley, Treasurer and
Margaret B.W. Graham                          Chief Financial Officer
Lisa M. Jones                               Christopher J. Kelley,Secretary and
Lorraine H. Monchak                           Chief Legal Officer
Marguerite A. Piret
Fred J. Ricciardi
Kenneth J. Taubes

Investment Adviser and Administrator Amundi
Pioneer Asset Management, Inc., formerly Pioneer Investment
Management, Inc.

Custodian and Sub-Administrator
Brown Brothers Harriman & Co.

Principal Underwriter
Amundi Pioneer Distributor, Inc., formerly Pioneer Funds Distributor, Inc.

Legal Counsel
Morgan, Lewis & Bockius LLP

Shareowner Services and Transfer Agent
Boston Financial Data Services, Inc.

Proxy Voting Policies and Procedures of the Fund are available without charge,
upon request, by calling our toll free number (1-800-225-6292). Information
regarding how the Fund voted proxies relating to portfolio securities during the
most recent 12-month period ended June 30 is publicly available to shareowners
at www.amundipioneer.com. This information is also available on the Securities
and Exchange Commission's web site at www.sec.gov.

60 Pioneer Emerging Markets Fund | Semiannual Report | 5/31/17


How to Contact Amundi Pioneer

We are pleased to offer a variety of convenient ways for you to contact us for
assistance or information.

Call us for:
--------------------------------------------------------------------------------
Account Information, including existing accounts, new accounts, prospectuses,
applications and service forms                                    1-800-225-6292

FactFone(SM) for automated fund yields, prices,
account information and transactions                              1-800-225-4321

Retirement plans information                                      1-800-622-0176

Write to us:
--------------------------------------------------------------------------------
Amundi Pioneer
P.O. Box 55014
Boston, Massachusetts 02205-5014

Our toll-free fax                                                 1-800-225-4240

Our internet e-mail address                  ask.amundipioneer@amundipioneer.com
(for general questions about Amundi Pioneer only)

Visit our web site: www.amundipioneer.com

This report must be preceded or accompanied by a prospectus.

The Fund files a complete schedule of investments with the Securities and
Exchange Commission for the first and third quarters for each fiscal year on
Form N-Q. Shareholders may view the filed Form N-Q by visiting the Commission's
web site at http://www.sec.gov. The filed form may also be viewed and copied at
the Commission's Public Reference Room in Washington, DC. Information regarding
the operations of the Public Reference Room may be obtained by calling
1-800-SEC-0330.


[LOGO]    Amundi Pioneer
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        ASSET MANAGEMENT

Amundi Pioneer Asset Management, Inc.
60 State Street
Boston, MA 02109
www.amundipioneer.com

Securities offered through Amundi Pioneer Distributor, Inc.
60 State Street, Boston, MA 02109
Underwriter of Pioneer Mutual Funds, Member SIPC
(C) 2017 Amundi Pioneer Asset Management 19387-11-0717