Pioneer Mid Cap Value Fund NCSR Certified annual shareholder report (management investment company)

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM N-CSR

CERTIFIED SHAREHOLDER REPORT OF REGISTERED

MANAGEMENT INVESTMENT COMPANIES

Investment Company Act file number 811-06106

Pioneer Mid Cap Value Fund

(Exact name of registrant as specified in charter)

60 State Street, Boston, MA 02109

(Address of principal executive offices) (ZIP code)

Terrence J. Cullen, Amundi Asset Management, Inc.,

60 State Street, Boston, MA 02109

(Name and address of agent for service)

Registrant’s telephone number, including area code: (617) 742-7825

Date of fiscal year end: October 31, 2021

Date of reporting period: November 1, 2020 through October 31, 2021

Form N-CSR is to be used by management investment companies to file reports with the Commission not later than 10 days after the transmission to stockholders of any report that is required to be transmitted to stockholders under Rule 30e-1 under the Investment Company Act of 1940 (17 CFR 270.30e-1). The Commission may use the information provided on Form N-CSR in its regulatory, disclosure review, inspection, and policymaking roles.

A registrant is required to disclose the information specified by Form N-CSR, and the Commission will make this information public. A registrant is not required to respond to the collection of information contained in Form N-CSR unless the Form displays a currently valid Office of Management and Budget (“OMB”) control number. Please direct comments concerning the accuracy of the information collection burden estimate and any suggestions for reducing the burden to Secretary, Securities and Exchange Commission, 450 Fifth Street, NW, Washington, DC 20549-0609. The OMB has reviewed this collection of information under the clearance requirements of 44 U.S.C. ss. 3507.

Pioneer Mid Cap

Value Fund

Annual Report | October 31, 2021


A: PCGRX	C: PCCGX	K: PMCKX	R: PCMRX	Y: PYCGX

visit us: www.amundi.com/us

Table of Contents
President’s Letter	2
Portfolio Management Discussion	4
Portfolio Summary	11
Prices and Distributions	12
Performance Update	13
Comparing Ongoing Fund Expenses	18
Schedule of Investments	20
Financial Statements	25
Notes to Financial Statements	34
Report of Independent Registered Public Accounting Firm	44
Additional Information	46
Statement Regarding Liquidity Risk Management Program	47
Approval of Renewal of Investment Management Agreement	49
Trustees, Officers and Service Providers	54

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President’s Letter

Dear Shareholders,

The past year and a half has created unprecedented challenges for investors, as the COVID-19 pandemic has not only dominated the headlines since March 2020, but has also led to significant changes in government and central-bank policies, both in the US and abroad, and affected the everyday lives of each of us. As we move into the final months of 2021, the situation, while improved, has continued to evolve.

Widespread distribution of the COVID-19 vaccines approved for emergency use in late 2020 led to a general decline in virus-related hospitalizations in the US and had a positive effect on overall market sentiment during the first half of this calendar year. The passage of two additional fiscal stimulus packages by US lawmakers last December and January also helped drive a strong market rally. However, the emergence of highly infectious variants of the virus has caused a recent spike in cases and hospitalizations, especially outside of the US. That development has contributed to a slowdown in the global economic recovery, as some foreign governments have reinstated strict virus-containment measures that had been relaxed after the rollout of the vaccines.

In the US, while performance of most asset classes, especially equities, has been positive for the year to date, volatility has been high, and the third quarter of 2021 saw negative returns for several stock market indices. Investors’ concerns over global supply chain issues, rising inflation, “hawkish” signals concerning less-accommodative future monetary policies from the Federal Reserve System (Fed), and partisan debates in Washington, DC over future spending and tax policies, are among the many factors that have led to greater uncertainty and an increase in market volatility.

Despite those concerns and some of the recent difficulties that have affected the economy and the markets, we believe the distribution of the COVID-19 vaccines has provided a potential light at the end of the pandemic tunnel. With that said, the long-term impact on the global economy from COVID-19, while currently unknown, is likely to be considerable, as it is clear that several industries have already felt greater effects than others, and could continue to struggle for quite some time.

After leaving our offices in March of 2020 due to COVID-19, we have re-opened our US locations and our employees have returned to the office as of mid-October. I am proud of the careful planning that has taken place.

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Throughout the pandemic, our business has continued to operate without any disruption, and we all look forward to regaining a bit of normalcy after so many months of remote working.

Since 1928, Amundi US’s investment process has been built on a foundation of fundamental research and active management, principles which have guided our investment decisions for more than 90 years. We believe active management – that is, making active investment decisions – can help mitigate the risks during periods of market volatility.

At Amundi US, active management begins with our own fundamental, bottom-up research process. Our team of dedicated research analysts and portfolio managers analyzes each security under consideration, communicating directly with the management teams of the companies issuing the securities and working together to identify those securities that best meet our investment criteria for our family of funds. Our risk management approach begins with each and every security, as we strive to carefully understand the potential opportunity, while considering any and all risk factors.

Today, as investors, we have many options. It is our view that active management can serve shareholders well, not only when markets are thriving, but also during periods of market stress.

As you consider your long-term investment goals, we encourage you to work with your financial professional to develop an investment plan that paves the way for you to pursue both your short-term and long-term goals.

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

Sincerely,

Lisa M. Jones

Head of the Americas, President and CEO of US

Amundi Asset Management US, Inc.

December 2021

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.

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Portfolio Management Discussion | 10/31/21

Domestic mid-cap stocks climbed sharply during the 12-month period ended October 31, 2021. In the following interview, Timothy Stanish and Raymond Haddad discuss the market environment and the factors that affected the performance of Pioneer Mid Cap Value Fund during the period. Mr. Stanish, a vice president, a portfolio EVA (economic value added) analyst, and a portfolio manager at Amundi Asset Management US, Inc. (Amundi US), and Mr. Haddad, a vice president and a portfolio manager at Amundi US, are responsible for the day-to-day management of the Fund.

How did the Fund perform during the 12-month period ended October 31, 2021?

Pioneer Mid Cap Value Fund’s Class A shares returned 43.21% at net asset value during the 12-month period ended October 31, 2021, while the Fund’s benchmark, the Russell Midcap Value Index (the Russell Index), returned 48.60%. During the same period, the average return of the 411 mutual funds in Morningstar’s Mid-Cap Value Funds category was 51.37%.

How would you describe the investment environment in the equity market during the 12-month period ended October 31, 2021?

The 12-month period saw US equities generally trend higher and finish with extremely strong gains, as the Standard & Poor’s 500 Index (the S&P 500), a broad measure of the domestic stock market, returned nearly 49% for the full 12 months. However, two distinct market environments prevailed during the 12-month period. Following the November 2020 US presidential election, the markets for riskier assets, such as equities, surged on the elimination of election uncertainty as well as the passage of an additional stimulus package from the US government, which further boosted investor sentiment. The first half of 2021 saw markets continue to rally, as accelerating COVID-19 vaccine distributions, the passage of yet another ($1.9 trillion) fiscal stimulus package by the US government, and further supportive messaging about monetary policy from the US Federal Reserve (Fed) helped market participants gain confidence in the prospects for a sharp economic recovery after roughly a year of lockdowns and other restrictive measures aimed at curbing the spread of COVID-19.

Later in the period, however, gains moderated. The rise of the “Delta” variant led to a spike in COVID-19 cases, which raised concerns about further possible business interruptions. In addition, worries about inflation, the future path of interest rates, a potential government

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shutdown, Washington gridlock, and the conditions of both the regulatory agencies and credit markets in China, contributed to a more cautious tone in the markets. The heightened uncertainty came to a head in September 2021, when the major domestic equity indices all declined, including the Fund’s benchmark, the Russell Index, which returned -3.68% for the month. However, the markets displayed continued resilience by rebounding sharply in October, the final month of the period, as the S&P 500 rose by 7% and the Russell Index returned 5.32%.

Within the US equity market, stocks of small- and mid-cap companies outperformed large-cap stocks over the 12-month period, reflecting investors’ increasing comfort level with taking on the higher risk of investing in smaller companies. Value stocks significantly outperformed growth stocks during the first half of the 12-month period, as market participants aggressively purchased economically sensitive “reopening” stocks of companies with greater exposure to the economic recovery cycle, and sold stocks of more secular growth-oriented companies with less cyclical exposure. That scenario favored value investors. Substantial increases in the yield on the 10-year US Treasury bond also weighed on the performance of growth stocks, especially those with high valuations based largely on corporate earnings results projected far into the future.

During the second half of the period, though, growth stocks rebounded and eliminated most of their relative underperformance versus value stocks, as the Russell 1000 Growth Index ended the 12-month period up by 43.21%, while the Russell 1000 Value Index returned 43.76%.

Within the Fund’s benchmark, cyclical sectors such as energy, financials, real estate, and materials stood out as strong performers over the 12-month period. Conversely, defensive sectors such as utilities, consumer staples, and health care were the benchmark’s laggards. Investors expressed a preference for what we viewed as low-quality over high-quality stocks during the period, generally ignoring quality factors such as low debt levels of companies, and high returns on assets.

How did you position the Fund’s portfolio during the 12-month period ended October 31, 2021, and how did the positioning affect the Fund’s benchmark-relative performance?

The Fund’s positioning during the 12-month period featured increased exposure to cyclical stocks in anticipation of further stimulus measures from the US government, the reopening of previously closed sectors of the economy, and the drawdown of savings accumulated by consumers during the “stay a home” environment that had prevailed for most of

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2020. The positioning reflected our belief that there was still value to be found in the sectors that had felt the worst effects of the initial spread of COVID-19. In particular, the Fund was most overweight versus the benchmark in the materials, consumer discretionary, and financials sectors, and was significantly underweight to communication services, utilities, consumer staples, and information technology.

Significant detractors from the Fund’s benchmark-relative returns during the period included stock selection results in the industrials and real estate sectors, as well as an underweight allocation to the energy sector, which rallied on higher oil and gas prices.

By contrast, stock selection results in consumer staples, as well as an underweight allocation to the sector, made the most significant positive contributions to the Fund’s benchmark-relative performance over the 12-month period. An underweight allocation to utilities also aided relative returns, as did stock selection within the information technology and consumer discretionary sectors.

Notable portfolio holdings that underperformed for the Fund versus the benchmark during the 12-month period included shares of discount retailer Dollar General, clean-energy electric utility Avangrid, and Zimmer Biomet, a manufacturer of medical equipment. After performing well for much of 2020, Dollar General’s stock experienced a sell-off during the period, and so we decided to close the Fund’s position, mainly for valuation reasons. We believe Avangrid has attractive exposure to clean-energy generation, but the company has faced ongoing challenges from regulators as it has attempted to finalize a potentially lucrative merger deal, and from pushback by political opponents on a key project. We chose to sell the Fund’s position in Avangrid in favor of buying shares of another utility company that we felt was trading at a more attractive valuation. Finally, Zimmer Biomet saw its stock price decline following a financial report that raised concerns about the company’s loss of market share in the surgical medical equipment segment. We opted to sell the Fund’s position in response.

Conversely, the largest positive contributors to the Fund’s relative performance among individual holdings during the 12-month period included shares of East West Bancorp, a regional bank; International Game Technology, a gambling-equipment specialist; and Marathon Petroleum, a downstream energy company. East West Bancorp benefited from favorable interest-rate trends that prevailed over most of the period, and we believe a furthering of the economic recovery could ease credit

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concerns and cause investors to take increased notice of East West’s attractive valuation in comparison to its peers. Shares of International Game Technology rebounded sharply from the steep losses the company had experienced throughout most of 2020, as economic reopenings in key markets across the globe led to improving conditions for the casino/gambling industry. Finally, Marathon Petroleum participated in the energy sector’s broad recovery over the 12-month period, as prices of crude oil and refined products rose and helped bolster the company’s refinery and retail gasoline operations.

Did the Fund have any exposure to derivative securities during the 12-month period ended October 31, 2021?

No, the Fund did not invest in any derivatives during the 12-month period.

What is your investment outlook and how have you positioned the Fund heading into a new fiscal year?

As we look ahead, we see several cross-currents affecting the financial markets. On one hand, pent-up consumer demand, a recovery in the industrial economy, lingering effects from the government’s fiscal stimulus, and continued distributions of regular and booster COVID-19 vaccinations could lead to positive economic growth and a potential full reopening of the economy at some point in 2022. We expect corporate earnings growth to be highest for companies with greater exposure to a cyclical economic recovery, and for those that had felt the worst effects of the onset of the pandemic and the related lockdowns, plus other restrictions on economic activity during 2020.

However, we believe the current political environment in Washington is particularly difficult to gauge. Despite the recent passage of the $1.2 trillion bipartisan infrastructure bill, several other potential headwinds to positive market sentiment remain, including proposals for higher taxes, ongoing negotiations for the reconciliation provisions of the Build Back Better Act, tensions with respect to a further extension of the federal debt ceiling, and expectations for tighter monetary policy from the Fed, given rising inflationary pressures. Until those issues get resolved, we see heightened volatility in stock markets as likely.

In addition, we believe there are more structural economic challenges that still must be overcome. Tight labor markets and high energy prices have been contributing to the aforementioned inflationary pressures. Bottlenecks in supply chains, too, could take time to resolve, and we have

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seen few signs that the recent price increases initially thought to be “transitory” in nature will go away any time soon. Despite expectations for accommodative Fed monetary policy to continue in the immediate future, the most worrying scenario, in our view, is that slower economic growth could combine with persistent inflation to produce “stagflation” conditions last seen in the 1970s and early 1980s.

Against that backdrop, we have maintained the Fund’s benchmark-relative overweight positions in the financials and materials sectors, and have increased exposure to the energy sector. We believe that the combination of widespread COVID-19 vaccine distributions and further fiscal stimulus (via infrastructure spending, at least) from the US government could spur sustained economic growth, although we have grown more cautious due to the rise in COVID-19 case counts driven by the Delta variant. However, we still believe we could see better performance for what we view as intrinsically undervalued stocks of companies in those more cyclical sectors. Within energy, we have favored owning shares of companies with less exposure to changes in oil prices. We have found the recent capital discipline displayed by energy companies to be admirable, and believe it could lead to future value creation if those policies remain in place.

By contrast, we have reduced the Fund’s exposure to some of the more cyclical, but what we view as lower-quality areas of the market, such as cruise line operators and airlines. We believe companies in those industries could face long-term structural headwinds, and view their stocks as potential, classic “value traps.” Airline stock prices, in our view, have already discounted a fair recovery, but we think air carriers might need to wait before business travel returns to pre-pandemic levels. Meanwhile, increased fuel costs are another potential headwind that has inclined us to remain “on the sidelines” with regard to the airline industry, pending greater certainty about the long-term prospects.

Finally, we have increased the Fund’s weighting in utilities stocks, based on our belief that valuations in the sector are attractive, particularly compared to historical levels. We believe the economic conditions affecting utilities have not changed enough over the past 18 months to warrant the reduced valuations, and we expect that trends favoring investments in renewable energy could propel future earnings growth for companies in the sector.

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Overall, we have remained committed to investing the Fund in companies that we view as highly profitable, and that have strong balance sheets as well as sustainable business models. In managing the portfolio, we seek to hold shares of companies that we feel are capable of surviving recessions, and then emerging with the financial firepower to invest and thrive during the subsequent recovery. We continue to believe that the Fund’s strategy is well-suited to the economic and market conditions that could prevail during the coming year, and beyond.

Please refer to the Schedule of Investments on pages 20–24 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 and heightened uncertainty. The market prices of securities 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, recessions, inflation, changes in interest or currency rates, lack of liquidity in the bond markets, the spread of infectious illness or other public health issues or adverse investor sentiment. These conditions may continue, recur, worsen or spread.

Investments in mid-sized companies may offer the potential for higher returns, but are also subject to greater short-term price fluctuations than investments in larger, more established companies.

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

The Fund invests in REIT securities, the value of which can fall for a variety of reasons, such as declines in rental income, fluctuating interest rates, poor property management, environmental liabilities, uninsured damage, increased competition, or changes in real estate tax laws.

When interest rates rise, the prices of fixed income securities in the fund will generally fall. Conversely, when interest rates fall, the prices of fixed income securities in the Fund will generally rise.

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These risks may increase share price volatility.

Before investing, consider the product’s investment objectives, risks, charges and expenses. Contact your advisor or Amundi Asset Management US, 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.

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Portfolio Summary | 10/31/21


10 Largest Holdings
(As a percentage of total investments)*
1.	McKesson Corp.	2.45%
2.	Marathon Petroleum Corp.	2.45
3.	Hartford Financial Services Group, Inc.	2.37
4.	Schlumberger, Ltd.	2.36
5.	M&T Bank Corp.	2.26
6.	Public Service Enterprise Group, Inc.	2.25
7.	Zions Bancorp N.A.	2.15
8.	CenterPoint Energy, Inc.	2.12
9.	Ingersoll Rand, Inc.	2.07
10.	First Republic Bank	1.95

*Excludes temporary cash investments and all derivative contracts except for options purchased. The Fund is actively managed, and current holdings may be different. The holdings listed should not be considered recommendations to buy or sell any securities.

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Prices and Distributions | 10/31/21

Net Asset Value per Share

Class	10/31/21	10/31/20
A	$28.99	$20.39
C	$18.93	$13.36
K	$29.06	$20.43
R	$28.20	$19.87
Y	$31.58	$22.19

Distributions per Share: 11/1/20–10/31/21

	Net Investment	Short-Term	Long-Term
Class	Income	Capital Gains	Capital Gains
A	$0.1673	$ —	$ —
C	$0.0319	$ —	$ —
K	$0.2398	$ —	$ —
R	$0.0987	$ —	$ —
Y	$0.2220	$ —	$ —

Index Definitions

The Russell Midcap Value Index is an unmanaged index that measures the performance of U.S. mid-cap value stocks. Index returns are calculated monthly, assume reinvestment of dividends and, unlike Fund returns, do not reflect any fees, expenses or sales charges. 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 13–17.

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Performance Update \| 10/31/21	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 Mid Cap Value Fund at public offering price during the periods shown, compared to that of the Russell Midcap Value Index.

Average Annual Total Returns
(As of October 31, 2021)
	Net	Public	Russell
	Asset	Offering	Midcap
	Value	Price	Value
Period	(NAV)	(POP)	Index
10 years	10.37%	9.72%	13.18%
5 years	9.94	8.65	12.30
1 year	43.21	34.97	48.60

Expense Ratio

(Per prospectus dated March 1, 2021)

Gross

1.08%

Call 1-800-225-6292 or visit www.amundi.com/us 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. POP returns reflect deduction of maximum 5.75% sales charge. NAV 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 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.

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Performance Update | 10/31/21

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 Mid Cap Value Fund during the periods shown, compared to that of the Russell Midcap Value Index.

Average Annual Total Returns
(As of October 31, 2021)
			Russell
			Midcap
	If	If	Value
Period	Held	Redeemed	Index
10 years	9.44%	N/A	13.18%
5 years	9.01	N/A	12.30
1 year	41.99	40.99%	48.60

Expense Ratio

(Per prospectus dated March 1, 2021)

Gross

1.96%

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

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. NAV returns would have been lower had sales charges been reflected. “If Redeemed” returns reflect deduction of the CDSC, assuming a complete redemption of shares at the last price calculated on the last business day of the period. 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.

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.

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Performance Update | 10/31/21

Class K Shares

Investment Returns

The mountain chart on the right shows the change in value of a $5 million investment made in Class K shares of Pioneer Mid Cap Value Fund during the periods shown, compared to that of the Russell Midcap Value Index.

Average Annual Total Returns
(As of October 31, 2021)
	Net	Russell
	Asset	Midcap
	Value	Value
Period	(NAV)	Index
10 years	10.63%	13.18%
5 years	10.32	12.30
1 year	43.72	48.60

Expense Ratio

(Per prospectus dated March 1, 2021)

Gross

0.72%

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

The performance shown for Class K shares for the period prior to the commencement of operations of Class K shares on March 2, 2015, is the net asset value performance of the Fund’s Class A shares, which has not been restated to reflect any differences in expenses, including Rule 12b-1 fees applicable to Class A shares. Since fees for Class A shares generally are higher than those of Class K shares, the performance of Class K shares prior to their inception on March 2, 2015, would have been higher than the performance shown. For the period beginning March 2, 2015, the actual performance of Class K shares is reflected. Class K 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.

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.

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Performance Update | 10/31/21

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 Mid Cap Value Fund during the periods shown, compared to that of the Russell Midcap Value Index.

Average Annual Total Returns
(As of October 31, 2021)
	Net	Russell
	Asset	Midcap
	Value	Value
Period	(NAV)	Index
10 years	9.94%	13.18%
5 years	9.48	12.30
1 year	42.54	48.60

Expense Ratio

(Per prospectus dated March 1, 2021)

Gross

1.42%

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

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.

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.

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Performance Update | 10/31/21

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 Mid Cap Value Fund during the periods shown, compared to that of the Russell Midcap Value Index.

Average Annual Total Returns
(As of October 31, 2021)
	Net	Russell
	Asset	Midcap
	Value	Value
Period	(NAV)	Index
10 years	10.69%	13.18%
5 years	10.21	12.30
1 year	43.58	48.60

Expense Ratio

(Per prospectus dated March 1, 2021)

Gross

0.81%

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

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.

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.

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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 ÷ $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 Mid Cap Value Fund

Based on actual returns from May 1, 2021 through October 31, 2021.

Share Class	A	C	K	R	Y
Beginning Account	$1,000.00	$1,000.00	$1,000.00	$1,000.00	$1,000.00
Value on 5/1/21
Ending Account	$1,038.73	$1,034.46	$1,040.85	$1,036.35	$1,039.91
Value on 10/31/21
Expenses Paid	$5.40	$9.95	$3.65	$7.75	$4.06
During Period*

Expenses are equal to the Fund's annualized expense ratio of 1.05%, 1.94%, 0.71%, 1.51%, and 0.79% for Class A, Class C, Class K, Class R and Class Y respectively, multiplied by the average account value over the period, multiplied by 183/365 (to reflect the one-half year period).

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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 Mid Cap Value Fund

Based on a hypothetical 5% per year return before expenses, reflecting the period from May 1, 2021 through October 31, 2021.

Share Class	A	C	K	R	Y
Beginning Account	$1,000.00	$1,000.00	$1,001.00	$1,000.00	$1,000.00
Value on 5/1/21
Ending Account	$1,019.91	$1,015.43	$1,021.63	$1,017.59	$1,021.22
Value on 10/31/21
Expenses Paid	$5.35	$9.86	$3.62	$7.68	$4.02
During Period*

Pioneer Mid Cap Value Fund | Annual Report | 10/31/21 19

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Schedule of Investments | 10/31/21


Shares			Value
		UNAFFILIATED ISSUERS — 96.2%
		COMMON STOCKS — 96.2% of Net Assets
		Aerospace & Defense — 0.9%
	172,983	Spirit AeroSystems Holdings, Inc.	$ 7,142,468
		Total Aerospace & Defense	$ 7,142,468
		Auto Components — 1.0%
	174,149	BorgWarner, Inc.	$ 7,848,895
		Total Auto Components	$ 7,848,895
		Banks — 10.7%
	262,955	Citizens Financial Group, Inc.	$ 12,458,808
	142,511	East West Bancorp, Inc.	11,326,774
	439,422	First Hawaiian, Inc.	12,123,653
	68,321	First Republic Bank	14,779,882
	116,755	M&T Bank Corp.	17,176,996
	259,114	Zions Bancorp N.A.	16,321,591
		Total Banks	$ 84,187,704
		Building Products — 1.5%
	65,931	Trane Technologies PLC	$ 11,928,896
		Total Building Products	$ 11,928,896
		Capital Markets — 2.8%
	62,920	Artisan Partners Asset Management, Inc.	$ 3,117,057
	331,478	Brightsphere Investment Group, Inc.	9,937,710
	42,640	Nasdaq, Inc.	8,948,857
		Total Capital Markets	$ 22,003,624
		Chemicals — 5.2%
	70,289	Celanese Corp.	$ 11,352,376
	84,143	Chemours Co.	2,357,687
	363,324	Element Solutions, Inc.	8,251,088
	157,028	Mosaic Co.	6,527,654
	80,240	PPG Industries, Inc.	12,884,137
		Total Chemicals	$ 41,372,942
		Communications Equipment — 1.4%
	44,869	Motorola Solutions, Inc.	$ 11,153,985
		Total Communications Equipment	$ 11,153,985
		Containers & Packaging — 2.1%
	37,504	Crown Holdings, Inc.	$ 3,900,041
	648,013	Graphic Packaging Holding Co.	12,914,899
		Total Containers & Packaging	$ 16,814,940
		Distributors — 1.0%
	149,473	LKQ Corp.	$ 8,232,973
		Total Distributors	$ 8,232,973

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

20 Pioneer Mid Cap Value Fund | Annual Report | 10/31/21

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Shares			Value
		Electric Utilities — 0.6%
	95,588	Exelon Corp.	$ 5,084,326
		Total Electric Utilities	$ 5,084,326
		Electrical Equipment — 1.7%
	81,367	Eaton Corp. Plc	$ 13,406,027
		Total Electrical Equipment	$ 13,406,027
		Electronic Equipment, Instruments & Components — 4.0%
	51,024	CDW Corp.	$ 9,523,629
	84,985	Dolby Laboratories, Inc.	7,508,425
	40,132(a)	Keysight Technologies, Inc.	7,224,563
	171,611	National Instruments Corp.	7,288,319
		Total Electronic Equipment, Instruments & Components	$ 31,544,936
		Energy Equipment & Services — 2.3%
	555,465	Schlumberger, Ltd.	$ 17,919,301
		Total Energy Equipment & Services	$ 17,919,301
		Equity Real Estate Investment Trusts (REITs) — 11.2%
	22,136	Alexandria Real Estate Equities, Inc.	$ 4,518,843
	19,424	AvalonBay Communities, Inc.	4,597,272
	35,306	Camden Property Trust	5,758,409
	102,683	Duke Realty Corp.	5,774,892
	36,005	Extra Space Storage, Inc.	7,106,307
	100,620	First Industrial Realty Trust, Inc.	5,859,103
	103,065	Healthcare Trust of America, Inc.	3,441,340
	72,319	Iron Mountain, Inc.	3,300,639
	410,859	Kimco Realty Corp.	9,285,413
	289,747	Outfront Media, Inc.	7,211,803
	72,042	SL Green Realty Corp.	5,047,983
	66,293	Sun Communities, Inc.	12,992,102
	146,343	UDR, Inc., Class REIT	8,126,427
	70,535	Welltower, Inc.	5,671,014
		Total Equity Real Estate Investment Trusts (REITs)	$ 88,691,547
		Food Products — 1.6%
	654,851(a)	Hostess Brands, Inc.	$ 12,383,232
		Total Food Products	$ 12,383,232
		Health Care Equipment & Supplies — 1.1%
	36,626	STERIS PLC	$ 8,560,961
		Total Health Care Equipment & Supplies	$ 8,560,961
		Health Care Providers & Services — 2.4%
	89,353	McKesson Corp.	$ 18,574,702
		Total Health Care Providers & Services	$ 18,574,702

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

Pioneer Mid Cap Value Fund | Annual Report | 10/31/21 21

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Schedule of Investments | 10/31/21

(continued)


Shares			Value
		Hotels, Restaurants & Leisure — 3.1%
	72,300	Darden Restaurants, Inc.	$ 10,421,322
	99,397(a)	Hilton Worldwide Holdings, Inc.	14,308,198
		Total Hotels, Restaurants & Leisure	$ 24,729,520
		Household Durables — 1.3%
	72,766	Lennar Corp.	$ 7,271,506
	123,209	Newell Brands, Inc.	2,820,254
		Total Household Durables	$ 10,091,760
		Insurance — 6.8%
	206,473	Aflac, Inc.	$ 11,081,406
	32,041	Assurant, Inc.	5,168,534
	246,284	Hartford Financial Services Group, Inc.	17,961,492
	99,029	Lincoln National Corp.	7,144,942
	473,953	Old Republic International Corp.	12,242,206
		Total Insurance	$ 53,598,580
		Internet & Direct Marketing Retail — 1.7%
	81,766(a)	Expedia, Inc.	$ 13,443,148
		Total Internet & Direct Marketing Retail	$ 13,443,148
		Life Sciences Tools & Services — 1.1%
	93,824(a)	Syneos Health, Inc.	$ 8,757,532
		Total Life Sciences Tools & Services	$ 8,757,532
		Machinery — 7.5%
	94,566	AGCO Corp.	$ 11,556,911
	106,309	Donaldson Co., Inc.	6,379,603
	194,573	Flowserve Corp.	6,541,544
	291,416	Ingersoll Rand, Inc.	15,666,524
	124,245	PACCAR, Inc.	11,134,837
	41,817	Stanley Black & Decker, Inc.	7,515,770
		Total Machinery	$ 58,795,189
		Materials — 1.3%
	166,884	Sealed Air Corp.	$ 9,899,559
		Total Materials	$ 9,899,559
		Media — 1.1%
	182,527(a)	Liberty Media Corp.-Liberty SiriusXM	$ 9,002,232
		Total Media	$ 9,002,232
		Metals & Mining — 2.7%
	121,993	Alcoa Corp.	$ 5,605,578
	102,394	Freeport-McMoRan, Inc.	3,862,302
	79,469	Reliance Steel & Aluminum Co.	11,615,189
		Total Metals & Mining	$ 21,083,069

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

22 Pioneer Mid Cap Value Fund | Annual Report | 10/31/21

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Shares			Value
		Multi-Utilities — 4.2%
	618,713	CenterPoint Energy, Inc.	$ 16,111,286
	268,057	Public Service Enterprise Group, Inc.	17,102,037
		Total Multi-Utilities	$ 33,213,323
		Oil, Gas & Consumable Fuels — 5.4%
	68,848	Cheniere Energy, Inc.	$ 7,118,883
	281,406	Marathon Petroleum Corp.	18,553,098
	36,076	Oasis Petroleum, Inc.	4,350,766
	67,524	Pioneer Natural Resources Co.	12,625,637
		Total Oil, Gas & Consumable Fuels	$ 42,648,384
		Pharmaceuticals — 1.0%
	204,869	Organon & Co.	$ 7,528,936
		Total Pharmaceuticals	$ 7,528,936
		Professional Services — 0.8%
	65,918	ManpowerGroup, Inc.	$ 6,370,975
		Total Professional Services	$ 6,370,975
		Real Estate Management & Development — 1.2%
	89,083(a)	CBRE Group, Inc.	$ 9,271,759
		Total Real Estate Management & Development	$ 9,271,759
		Road & Rail — 1.5%
	60,092	JB Hunt Transport Services, Inc.	$ 11,849,541
		Total Road & Rail	$ 11,849,541
		Semiconductors & Semiconductor Equipment — 1.2%
	63,248	MKS Instruments, Inc.	$ 9,490,362
		Total Semiconductors & Semiconductor Equipment	$ 9,490,362
		Software — 1.0%
	45,020(a)	Manhattan Associates, Inc.	$ 8,172,931
		Total Software	$ 8,172,931
		Specialty Retail — 1.8%
	22,217(a)	O’Reilly Automotive, Inc.	$ 13,826,083
		Total Specialty Retail	$ 13,826,083
		TOTAL COMMON STOCKS
		(Cost $569,902,762)	$758,624,342
		TOTAL INVESTMENTS IN UNAFFILIATED ISSUERS — 96.2%
		(Cost $569,902,762)	$758,624,342
		OTHER ASSETS AND LIABILITIES — 3.8%	$ 29,873,189
		NET ASSETS — 100.0%	$788,497,531

REIT Real Estate Investment Trust.

(a) Non-income producing security.

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

Pioneer Mid Cap Value Fund | Annual Report | 10/31/21 23

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Schedule of Investments | 10/31/21

(continued)

Purchases and sales of securities (excluding temporary cash investments) for the year ended October 31, 2021, aggregated $488,330,263 and $574,076,792, respectively.

The Fund is permitted to engage in purchase and sale transactions (“cross trades”) with certain funds and accounts for which Amundi Asset Management US, Inc. (the "Adviser") 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 year ended October 31, 2021, the Fund did not engage in any cross trade activity.

At October 31, 2021, the net unrealized appreciation on investments based on cost for federal tax purposes of $570,321,256 was as follows:

Aggregate gross unrealized appreciation for all investments in which
there is an excess of value over tax cost	$191,909,451
Aggregate gross unrealized depreciation for all investments in which
there is an excess of tax cost over value	(3,906,455)
Net unrealized appreciation	$188,003,086

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

Level 1 – unadjusted 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 risks, 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 October 31, 2021, in valuing the Fund's investments:

	Level 1		Level 2		Level 3		Total
Common Stocks	$	758,624,342	$	—	$	—	$	758,624,342
Total Investments
in Securities	$	758,624,342	$	—	$	—	$	758,624,342

During the year ended October 31, 2021, there were no transfers in or out of Level 3.

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

24 Pioneer Mid Cap Value Fund | Annual Report | 10/31/21

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Statement of Assets and Liabilities | 10/31/21

ASSETS:
Investments in unaffiliated issuers, at value (cost $569,902,762)	$	758,624,342
Cash		27,072,288
Receivables —
Investment securities sold		3,899,151
Fund shares sold		58,106
Dividends		428,309
Other assets		27,616
Total assets	$	790,109,812
LIABILITIES:
Payables —
Fund shares repurchased		1,292,241
Distributions		679
Trustees' fees		2,840
Administrative fees		16,715
Transfer agent fees		126,183
Due to affiliates		32,790
Management fees		75,116
Accrued expenses		65,717
Total liabilities	$	1,612,281
NET ASSETS:
Paid-in capital	$	499,785,304
Distributable earnings		288,712,227
Net assets	$	788,497,531
NET ASSET VALUE PER SHARE:
No par value (unlimited number of shares authorized)
Class A (based on $744,113,391/25,665,423 shares)	$	28.99
Class C (based on $10,784,961/569,842 shares)	$	18.93
Class K (based on $832,470/28,651 shares)	$	29.06
Class R (based on $8,245,421/292,341 shares)	$	28.20
Class Y (based on $24,521,288/776,390 shares)	$	31.58
MAXIMUM OFFERING PRICE PER SHARE:
Class A (based on $28.99 net asset value per share/100%-5.75%
maximum sales charge)	$	30.76

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

Pioneer Mid Cap Value Fund | Annual Report | 10/31/21 25

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Statement of Operations
FOR THE YEAR ENDED 10/31/21

INVESTMENT INCOME:
Dividends from unaffiliated issuers	$12,614,816
Interest from unaffiliated issuers	1,008
Total investment income		$ 12,615,824
EXPENSES:
Management fees
Basic Fee	$ 5,102,185
Performance adjustment	(669,876)
Administrative expense	342,763
Transfer agent fees
Class A	639,964
Class C	20,003
Class K	59
Class R	24,681
Class Y	21,054
Distribution fees
Class A	1,765,182
Class C	105,123
Class R	39,937
Shareowner communications expense	200,616
Custodian fees	13,994
Registration fees	74,696
Professional fees	85,400
Printing expense	39,062
Trustees' fees	33,204
Insurance expense	1,455
Miscellaneous	94,834
Total expenses		$ 7,934,336
Net investment income		$ 4,681,488
REALIZED AND UNREALIZED GAIN (LOSS) ON INVESTMENTS:
Net realized gain (loss) on:
Investments in unaffiliated issuers		$145,140,112
Change in net unrealized appreciation (depreciation) on:
Investments in unaffiliated issuers		$102,365,286
Net realized and unrealized gain (loss) on investments		$247,505,398
Net increase in net assets resulting from operations		$252,186,886

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

26 Pioneer Mid Cap Value Fund | Annual Report | 10/31/21

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Statements of Changes in Net Assets

	Year Ended	Year Ended
	10/31/21	10/31/20
FROM OPERATIONS:
Net investment income (loss)	$ 4,681,488	$ 6,044,927
Net realized gain (loss) on investments	145,140,112	(47,590,307)
Change in net unrealized appreciation (depreciation)
on investments	102,365,286	(30,210,660)
Net increase (decrease) in net assets resulting
from operations	$252,186,886	$ (71,756,040)
DISTRIBUTIONS TO SHAREOWNERS:
Class A ($0.17 and $0.25 per share, respectively)	$ (4,608,921)	$ (7,700,900)
Class C ($0.03 and $0.13 per share, respectively)	(19,531)	(113,939)
Class K ($0.24 and $0.34 per share, respectively)	(5,413)	(22,868)
Class R ($0.10 and $0.16 per share, respectively)	(33,607)	(68,355)
Class Y ($0.22 and $0.31 per share, respectively)	(154,858)	(337,280)
Total distributions to shareowners	$ (4,822,330)	$ (8,243,342)
FROM FUND SHARE TRANSACTIONS:
Net proceeds from sales of shares	$ 28,608,017	$ 22,696,201
Reinvestment of distributions	4,598,938	7,883,986
Cost of shares repurchased	(95,997,067)	(110,159,480)
Net decrease in net assets resulting from Fund
share transactions	$ (62,790,112)	$ (79,579,293)
Net increase (decrease) in net assets	$184,574,444	$(159,578,675)
NET ASSETS:
Beginning of year	$603,923,087	$ 763,501,762
End of year	$788,497,531	$ 603,923,087

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

Pioneer Mid Cap Value Fund | Annual Report | 10/31/21 27

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Statements of Changes in Net Assets

(continued)

	Year	Year	Year	Year
	Ended	Ended	Ended	Ended
	10/31/21	10/31/21	10/31/20	10/31/20
	Shares	Amount	Shares	Amount
Class A
Shares sold	705,253	$ 18,522,202	745,173	$ 15,119,695
Reinvestment of distributions	190,436	4,395,290	318,443	7,365,829
Less shares repurchased	(3,274,770)	(84,673,482)	(4,230,341)	(86,767,920)
Net decrease	(2,379,081)	$(61,755,990)	(3,166,725)	$(64,282,396)
Class C
Shares sold	110,850	$ 1,923,613	111,134	$ 1,476,051
Reinvestment of distributions	1,290	19,531	7,347	111,863
Less shares repurchased	(244,527)	(4,078,275)	(338,596)	(4,468,817)
Net decrease	(132,387)	$ (2,135,131)	(220,115)	$ (2,880,903)
Class K
Shares sold	11,280	$ 307,295	27,157	$ 488,529
Reinvestment of distributions	212	4,894	988	22,868
Less shares repurchased	(5,770)	(147,857)	(73,298)	(1,476,228)
Net increase (decrease)	5,722	$ 164,332	(45,153)	$ (964,831)
Class R
Shares sold	48,109	$ 1,254,346	50,614	$ 954,252
Reinvestment of distributions	1,482	33,413	3,002	67,720
Less shares repurchased	(104,175)	(2,618,411)	(149,217)	(3,027,700)
Net decrease	(54,584)	$ (1,330,652)	(95,601)	$ (2,005,728)
Class Y
Shares sold	233,078	$ 6,600,561	203,977	$ 4,657,674
Reinvestment of distributions	5,811	145,810	12,567	315,706
Less shares repurchased	(157,014)	(4,479,042)	(642,760)	(14,418,815)
Net increase (decrease)	81,875	$ 2,267,329	(426,216)	$ (9,445,435)

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

28 Pioneer Mid Cap Value Fund | Annual Report | 10/31/21

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Financial Highlights

	Year	Year	Year	Year	Year
	Ended	Ended	Ended	Ended	Ended
	10/31/21	10/31/20	10/31/19	10/31/18	10/31/17
Class A
Net asset value, beginning of period	$ 20.39	$ 22.77	$ 22.50	$ 26.27	$ 23.66
Increase (decrease) from investment operations:
Net investment income (loss) (a)	$ 0.17	$ 0.19	$ 0.18	$ 0.16	$ 0.11
Net realized and unrealized gain (loss) on investments	8.60	(2.32)	2.36	(1.82)	4.10
Net increase (decrease) from investment operations	$ 8.77	$ (2.13)	$ 2.54	$ (1.66)	$ 4.21
Distributions to shareowners:
Net investment income	$ (0.17)	$ (0.17)	$ (0.18)	$ (0.09)	$ (0.11)
Net realized gain	—	(0.08)	(2.09)	(2.02)	(1.49)
Total distributions	$ (0.17)	$ (0.25)	$ (2.27)	$ (2.11)	$ (1.60)
Net increase (decrease) in net asset value	$ 8.60	$ (2.38)	$ 0.27	$ (3.77)	$ 2.61
Net asset value, end of period	$ 28.99	$ 20.39	$ 22.77	$ 22.50	$ 26.27
Total return (b)	43.21%	(9.48)%	12.44%(c)	(7.05)%	18.56%
Ratio of net expenses to average net assets	1.05%	1.08%	1.06%	1.02%	1.04%
Ratio of net investment income (loss) to average net assets	0.64%	0.94%	0.85%	0.63%	0.43%
Portfolio turnover rate	68%	65%	94%	78%	58%
Net assets, end of period (in thousands)	$744,113	$571,772	$710,565	$710,468	$839,636

(a)

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

(b)

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.

(c)

If the Fund had not recognized gains in settlement of class action lawsuits during the year ended October 31, 2019, the total return would have been 12.34%.

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

Pioneer Mid Cap Value Fund | Annual Report | 10/31/21 29

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Financial Highlights (continued)

	Year	Year	Year	Year	Year
	Ended	Ended	Ended	Ended	Ended
	10/31/21	10/31/20	10/31/19	10/31/18	10/31/17
Class C
Net asset value, beginning of period	$ 13.36	$ 15.01	$ 15.53	$ 18.82	$ 17.42
Increase (decrease) from investment operations:
Net investment income (loss) (a)	$ (0.04)	$ 0.01	$ (0.00)(b)	$ (0.03)	$ (0.07)
Net realized and unrealized gain (loss) on investments	5.64	(1.53)	1.57	(1.24)	2.96
Net increase (decrease) from investment operations	$ 5.60	$ (1.52)	$ 1.57	$ (1.27)	$ 2.89
Distributions to shareowners:
Net investment income	$ (0.03)	$ (0.05)	$ —	$ —	$ —
Net realized gain	—	(0.08)	(2.09)	(2.02)	(1.49)
Total distributions	$ (0.03)	$ (0.13)	$ (2.09)	$ (2.02)	$ (1.49)
Net increase (decrease) in net asset value	$ 5.57	$ (1.65)	$ (0.52)	$ (3.29)	$ 1.40
Net asset value, end of period	$ 18.93	$ 13.36	$ 15.01	$ 15.53	$ 18.82
Total return (c)	41.99%	(10.25)%	11.40%(d)	(7.77)%(e)	17.55%
Ratio of net expenses to average net assets	1.94%	1.96%	1.94%	1.83%	1.87%
Ratio of net investment income (loss) to average net assets	(0.24)%	0.07%	(0.01)%	(0.15)%	(0.40)%
Portfolio turnover rate	68%	65%	94%	78%	58%
Net assets, end of period (in thousands)	$10,785	$ 9,380	$13,845	$18,495	$48,840

(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 per share.

(c)

(d)

If the Fund had not recognized gains in settlement of class action lawsuits during the year ended October 31, 2019, the total return would have been 11.31%.

(e)

If the Fund had not recognized gains in settlement of class action lawsuits during the year ended October 31, 2018, the total return would have been (7.82)% .

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

30 Pioneer Mid Cap Value Fund | Annual Report | 10/31/21

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	Year	Year	Year	Year	Year
	Ended	Ended	Ended	Ended	Ended
	10/31/21	10/31/20	10/31/19	10/31/18	10/31/17
Class K
Net asset value, beginning of period	$20.43	$22.82	$22.56	$26.34	$ 23.72
Increase (decrease) from investment operations:
Net investment income (loss) (a)	$ 0.26	$ 0.26	$ 0.26	$ 0.21	$ 0.19
Net realized and unrealized gain (loss) on investments	8.61	(2.31)	2.34	(1.79)	4.11
Net increase (decrease) from investment operations	$ 8.87	$ (2.05)	$ 2.60	$ (1.58)	$ 4.30
Distributions to shareowners:
Net investment income	$ (0.24)	$ (0.26)	$ (0.25)	$ (0.18)	$ (0.19)
Net realized gain	—	(0.08)	(2.09)	(2.02)	(1.49)
Total distributions	$ (0.24)	$ (0.34)	$ (2.34)	$ (2.20)	$ (1.68)
Net increase (decrease) in net asset value	$ 8.63	$ (2.39)	$ 0.26	$ (3.78)	$ 2.62
Net asset value, end of period	$29.06	$20.43	$22.82	$22.56	$ 26.34
Total return (b)	43.72%	(9.17)%	12.83%(c)	(6.75)%(d)	18.98%
Ratio of net expenses to average net assets	0.71%	0.72%	0.69%	0.68%	0.68%
Ratio of net investment income (loss) to average net assets	0.98%	1.29%	1.23%	0.83%	0.74%
Portfolio turnover rate	68%	65%	94%	78%	58%
Net assets, end of period (in thousands)	$ 832	$ 468	$1,554	$1,693	$26,373

(a)

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

(b)

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

(c)

If the Fund had not recognized gains in settlement of class action lawsuits during the year ended October 31, 2019, the total return would have been 12.76%.

(d)

If the Fund had not recognized gains in settlement of class action lawsuits during the year ended October 31, 2018, the total return would have been (6.80)% .

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

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Financial Highlights (continued)

	Year	Year	Year	Year	Year
	Ended	Ended	Ended	Ended	Ended
	10/31/21	10/31/20	10/31/19	10/31/18	10/31/17
Class R
Net asset value, beginning of period	$19.87	$22.18	$21.94	$ 25.70	$ 23.18
Increase (decrease) from investment operations:
Net investment income (loss) (a)	$ 0.05	$ 0.12	$ 0.09	$ 0.04	$ 0.00(b)
Net realized and unrealized gain (loss) on investments	8.38	(2.27)	2.31	(1.78)	4.02
Net increase (decrease) from investment operations	$ 8.43	$ (2.15)	$ 2.40	$ (1.74)	$ 4.02
Distributions to shareowners:
Net investment income	$ (0.10)	$ (0.08)	$ (0.07)	$ —	$ (0.01)
Net realized gain	—	(0.08)	(2.09)	(2.02)	(1.49)
Total distributions	$ (0.10)	$ (0.16)	$ (2.16)	$ (2.02)	$ (1.50)
Net increase (decrease) in net asset value	$ 8.33	$ (2.31)	$ 0.24	$ (3.76)	$ 2.52
Net asset value, end of period	$28.20	$19.87	$22.18	$ 21.94	$ 25.70
Total return (c)	42.54%	(9.79)%	11.97%(d)	(7.50)%	18.11%
Ratio of net expenses to average net assets	1.51%	1.42%	1.47%	1.48%	1.46%
Ratio of net investment income (loss) to average net assets	0.18%	0.61%	0.45%	0.18%	0.02%
Portfolio turnover rate	68%	65%	94%	78%	58%
Net assets, end of period (in thousands)	$8,245	$6,893	$9,814	$10,244	$14,579

(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 per share.

(c)

(d)

If the Fund had not recognized gains in settlement of class action lawsuits during the year ended October 31, 2019, the total return would have been 11.87%.

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

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	Year	Year	Year	Year	Year
	Ended	Ended	Ended	Ended	Ended
	10/31/21	10/31/20	10/31/19	10/31/18	10/31/17
Class Y
Net asset value, beginning of period	$ 22.19	$ 24.74	$ 24.26	$ 28.16	$ 25.25
Increase (decrease) from investment operations:
Net investment income (loss) (a)	$ 0.26	$ 0.28	$ 0.25	$ 0.23	$ 0.18
Net realized and unrealized gain (loss) on investments	9.35	(2.52)	2.55	(1.97)	4.38
Net increase (decrease) from investment operations	$ 9.61	$ (2.24)	$ 2.80	$ (1.74)	$ 4.56
Distributions to shareowners:
Net investment income	$ (0.22)	$ (0.23)	$ (0.23)	$ (0.14)	$ (0.16)
Net realized gain	—	(0.08)	(2.09)	(2.02)	(1.49)
Total distributions	$ (0.22)	$ (0.31)	$ (2.32)	$ (2.16)	$ (1.65)
Net increase (decrease) in net asset value	$ 9.39	$ (2.55)	$ 0.48	$ (3.90)	$ 2.91
Net asset value, end of period	$ 31.58	$ 22.19	$ 24.74	$ 24.26	$ 28.16
Total return (b)	43.58%	(9.23)%	12.70%(c)	(6.85)%	18.85%
Ratio of net expenses to average net assets	0.79%	0.81%	0.82%	0.78%	0.81%
Ratio of net investment income (loss) to average net assets	0.89%	1.25%	1.08%	0.88%	0.66%
Portfolio turnover rate	68%	65%	94%	78%	58%
Net assets, end of period (in thousands)	$24,521	$15,409	$27,724	$27,410	$39,423

(a)

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

(b)

(c)

If the Fund had not recognized gains in settlement of class action lawsuits during the year ended October 31, 2019, the total return would have been 12.60%.

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

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Notes to Financial Statements | 10/31/21

1. Organization and Significant Accounting Policies

Pioneer Mid Cap Value 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 to seek capital appreciation by investing in a diversified portfolio of securities consisting primarily of common stocks.

The Fund offers five classes of shares designated as Class A, Class C, Class K, 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 shareowner approval. Under per share voting, each share of a class of the Fund is entitled to one vote. Under dollar-weighted voting, a shareowner’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.

Amundi Asset Management US, Inc., an indirect, wholly owned subsidiary of Amundi and Amundi’s wholly owned subsidiary, Amundi USA, Inc., serves as the Fund’s investment adviser (the “Adviser”). Prior to January 1, 2021, the Adviser was named Amundi Pioneer Asset Management, Inc. Amundi Distributor US, Inc., an affiliate of the Adviser, serves as the Fund’s distributor (the “Distributor”).

In August 2018, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update 2018-13 “Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement” (“ASU 2018-13”) which modifies disclosure requirements for fair value measurements, principally for Level 3 securities and transfers between levels of the fair value hierarchy. ASU 2018-13 is effective for fiscal years beginning after December 15, 2019 and for interim periods within those fiscal years. The Fund has adopted ASU 2018-13 for the year ended October 31, 2021. The impact to the Fund’s adoption was limited to changes in the Fund’s disclosures regarding fair value, primarily those disclosures related to

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transfers between levels of the fair value hierarchy and disclosure of the range and weighted average used to develop significant unobservable inputs for Level 3 fair value investments, when applicable.

In March 2020, FASB issued an Accounting Standard Update, ASU 2020-04, Reference Rate Reform (Topic 848) — Facilitation of the Effects of Reference Rate Reform on Financial Reporting (“ASU 2020-04”), which provides optional, temporary relief with respect to the financial reporting of contracts subject to certain types of modifications due to the planned discontinuation of the London Interbank Offered Rate (“LIBOR”) and other LIBOR-based reference rates at the end of 2021. The temporary relief provided by ASU 2020-04 is effective for certain reference rate-related contract modifications that occur during the period from March 12, 2020 through December 31, 2022. Management is evaluating the impact of ASU 2020-04 on the Fund’s investments, derivatives, debt and other contracts, if applicable, that will undergo reference rate-related modifications as a result of the reference rate reform.

The Fund is an investment company and follows investment company accounting and reporting guidance under U.S. Generally Accepted Accounting Principles (“U.S. GAAP”). U.S. GAAP requires the management of the Fund to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets 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 following is a summary of significant accounting policies followed by the Fund in the preparation of its financial statements:

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.

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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 the Adviser pursuant to procedures adopted by the Fund’s Board of Trustees. The Adviser’s fair valuation team uses fair value methods approved by the Valuation Committee of the Board of Trustees. The Adviser’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 October 31, 2021, no securities were valued using fair value methods (other than securities valued using prices supplied by independent pricing services, broker-dealers or a third party insurance industry valuation model).

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 and net of income accrued on defaulted securities.

Interest and dividend income payable by delivery of additional shares is reclassified as PIK (payment-in-kind) income upon receipt and is included in interest and dividend income, respectively.

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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.

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 October 31, 2021, 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 on the Statement of Operations. Tax returns filed within the prior three years remain subject to examination by federal and state tax authorities.

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 over distributions 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.

A portion of the dividend income recorded by the Fund is from distributions by publicly traded real estate investment trusts (“REITs”), and such distributions for tax purposes may also consist of capital gains and return of capital. The actual return of capital and capital gains portions of such distributions will be determined by formal notifications from the REITs subsequent to the calendar year-end. Distributions received from the REITs that are determined to be a return of capital are recorded by the Fund as a reduction of the cost basis of the securities held and those determined to be capital gain are reflected as such on the Statement of Operations.

At October 31, 2021, the Fund was permitted to carry forward indefinitely $47,199,272 of short-term losses.

The tax character of distributions paid during the years ended October 31, 2021 and October 31, 2020, were as follows:

	2021	2020
Distributions paid from:
Ordinary income	$4,822,330	$5,724,260
Long-term capital gain	—	2,519,082
Total	$4,822,330	$8,243,342

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The following shows the components of distributable earnings (losses) on a federal income tax basis at October 31, 2021:

	2021
Undistributed ordinary income	$ 3,364,311
Undistributed Long Term Capital Gain	97,344,830
Net unrealized appreciation	188,003,086
Total	$288,712,227

The difference between book basis and tax basis unrealized appreciation is attributable to the tax deferral of losses on wash sales.

Fund Shares

The Fund records sales and repurchases of its shares as of trade date. The Distributor earned $24,126 in underwriting commissions on the sale of Class A shares during the year ended October 31, 2021.

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 K and 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 K, Class R and Class Y shares can reflect different transfer agent and distribution expense rates.

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, recessions, the spread of infectious illness or other public health issues, inflation, changes in interest rates, lack of liquidity in the bond markets or adverse

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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. A general rise in interest rates could adversely affect the price and liquidity of fixed-income securities.

The Portfolio may invest in REIT securities, the value of which can fall for a variety of reasons, such as declines in rental income, fluctuating interest rates, poor property management, environmental liabilities, uninsured damage, increased competition, or changes in real estate tax laws.

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 and sectors. The Fund’s investments in foreign markets and countries with limited developing markets may subject the Fund to a greater degree of risk than investments in a developed market. These risks include disruptive political or economic conditions and the imposition of adverse governmental laws or currency exchange restrictions.

With the increased use of technologies such as the Internet to conduct business, the Fund is susceptible to operational, information security and related risks. While the Fund’s Adviser has established business continuity plans in the event of, and risk management systems to prevent, limit or mitigate, such cyber-attacks, there are inherent limitations in such plans and systems, including the possibility that certain risks have not been identified. Furthermore, the Fund cannot control the cybersecurity plans and systems put in place by service providers to the Fund such as the Fund’s custodian and accounting agent and the Fund’s transfer agent. In addition, many beneficial owners of Fund shares hold them through accounts at broker-dealers, retirement platforms and other financial market participants over which neither the Fund nor the Adviser exercises control. Each of these may in turn rely on service providers to them, which are also subject to the risk of cyber-attacks. Cybersecurity failures or breaches at the Adviser or the Fund’s service providers or intermediaries have the ability to cause disruptions and impact business operations, potentially resulting in financial losses, interference with the Fund’s ability to calculate its net asset value, impediments to trading, the inability of Fund shareowners to effect share purchases, redemptions or exchanges or receive distributions, loss of or unauthorized access to private shareowner information and violations of applicable privacy and other laws, regulatory fines, penalties, reputational damage, or additional compliance costs. Such costs and losses may not be covered under any insurance. In addition,

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maintaining vigilance against cyber-attacks may involve substantial costs over time, and system enhancements may themselves be subject to cyber-attacks.

COVID-19

The global pandemic of the novel coronavirus respiratory disease designated COVID-19 has resulted in major disruption to economies and markets around the world, including the United States. Global financial markets have experienced extreme volatility and severe losses, and trading in many instruments has been disrupted. Liquidity for many instruments has been greatly reduced for periods of time. Some interest rates are very low and in some cases yields are negative. Some sectors of the economy and individual issuers have experienced particularly large losses. Rates of inflation have recently risen. These circumstances may continue for an extended period of time, and may continue to affect adversely the value and liquidity of the Fund’s investments. Governments and central banks, including the Federal Reserve in the U.S., have taken extraordinary and unprecedented actions to support local and global economies and the financial markets. These actions have resulted in significant expansion of public debt, including in the U.S. The impact of these measures will not be known for some time. The consequences of high public debt, including its future impact on the economy and securities markets, likewise may not be known for some time.

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

The Adviser manages the Fund’s portfolio. Management fees payable under the Fund’s Investment Management Agreement with the Adviser are calculated daily and paid monthly at the annual rate of 0.70% of the Fund’s average daily net assets up to $500 million, 0.65% on the next $500 million, 0.625% on the next $3 billion and 0.60% on the excess over $4 billion. The basic fee (fee before performance adjustment) can increase or decrease by a maximum of 0.10% based on the investment performance of the Fund’s Class A shares as compared to the Russell Midcap Value Index. The performance comparison is made for a rolling 36-month period. In addition, the Adviser contractually limits any positive adjustment of the Fund’s management fee to 0.10% of the Fund’s average daily net assets on an annual basis (i.e., to a maximum management fee of 0.80% of average daily net assets after the performance adjustment). For the year ended October 31, 2021, the aggregate performance adjustment resulted in a

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decrease of $669,876 to the basic fee. For the year ended October 31, 2021, the net management fee was equivalent to 0.59% of the Fund’s average daily net assets.

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 $68,294 in management fees, administrative costs and certain other reimbursements payable to the Adviser at October 31, 2021.

3. Compensation of Trustees and Officers

The Fund pays an annual fee to its Trustees. The Adviser reimburses the Fund for fees paid to the Interested Trustees. The Fund does not pay any salary or other compensation to its officers. For the year ended October 31, 2021, the Fund paid $33,204 in Trustees’ compensation, which is reflected on the Statement of Operations as Trustees’ fees. At October 31, 2021, the Fund had a payable for Trustees’ fees on its Statement of Assets and Liabilities of $2,840.

4. Transfer Agent

During the period covered by the report DST Asset Manager Solutions, Inc. served 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 shareowner communications activities such as proxy and statement mailings, and outgoing phone calls. For the year ended October 31, 2021, such out-of-pocket expenses by class of shares were as follows:

Shareowner Communications:
Class A	$191,346
Class C	6,348
Class K	58
Class R	1,364
Class Y	1,500
Total	$200,616

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5. 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 the Distributor 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 the Distributor 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 the Distributor 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 $39,613 in distribution fees payable to the Distributor at October 31, 2021.

The Fund also has adopted a separate service plan for Class R shares (the “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 Class A and Class C 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 K, Class R or Class Y shares. Proceeds from the CDSCs are paid to the Distributor. For the year ended October 31, 2021, CDSCs in the amount of $1,412 were paid to the Distributor.

6. Line of Credit Facility

The Fund, along with certain other funds in the Pioneer Family of 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 credit facility or the limits set for borrowing by the Fund’s prospectus and the 1940 Act. Effective February 3, 2021, the Fund participates in a facility in the amount

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of $450 million. Under such facility, depending on the type of loan, interest on borrowings is payable at the London Interbank Offered Rate (“LIBOR”) plus a credit spread. The Fund also pays both an upfront fee and an annual commitment fee to participate in the credit facility. The upfront fee in the amount of 0.10% of the total credit facility and the commitment fee in the amount of 0.25% of the daily unused portion of each lender’s commitment are allocated among participating funds based on an allocation schedule set forth in the credit agreement. For the year ended October 31, 2021, the Fund had no borrowings under the credit facility.

7. Subsequent Event

Effective November 22, 2021, fund services transitioned to The Bank of New York Mellon Corporation (“BNY Mellon”). BNY Mellon is now the Fund's Transfer Agent, Custodian and Sub-Administrator.

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Report of Independent Registered Public Accounting Firm

To the Board of Trustees and the Shareholders of Pioneer Mid Cap Value Fund:

Opinion on the Financial Statements

We have audited the accompanying statement of assets and liabilities of Pioneer Mid Cap Value Fund (the “Fund”), including the schedule of investments, as of October 31, 2021, and the related statement of operations for the year then ended, the statements of changes in net assets for each of the two years in the period then ended, the financial highlights for each of the five years in the period then ended and the related notes (collectively referred to as the “financial statements”). In our opinion, the financial statements present fairly, in all material respects, the financial position of Pioneer Mid Cap Value Fund at October 31, 2021, the results of its operations for the year then ended, the changes in its net assets for each of the two years in the period then ended, and its financial highlights for each of the five years in the period then ended in conformity with U.S. generally accepted accounting principles.

Basis for Opinion

These financial statements are the responsibility of the Fund’s management. Our responsibility is to express an opinion on the Fund’s financial statements based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) (“PCAOB”) and are required to be independent with respect to the Fund in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud. The Fund is not required to have, nor were we engaged to perform, an audit of the Fund’s internal control over financial reporting. As part of our audits, we are required to obtain an understanding of internal control over financial reporting, but not for the purpose of expressing an opinion on the effectiveness of the Fund’s internal control over financial reporting. Accordingly, we express no such opinion.

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Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our procedures included confirmation of securities owned as of October 31, 2021, by correspondence with the custodian and brokers or by other appropriate auditing procedures where replies from brokers were not received. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. We believe that our audits provide a reasonable basis for our opinion.

We have served as the auditor of one or more investment companies in the Pioneer family of funds since 2017.

Boston, Massachusetts
December 22, 2021

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Additional Information (unaudited)

For the year ended October 31, 2021, certain dividends paid by the Fund may be subject to a maximum tax rate of 20%, as provided for by the Jobs and Growth Tax Relief Reconciliation Act (the Act) of 2003. The Fund intends to designate up to the maximum amount of such dividends allowable under the Act, as taxed at a maximum rate of 20%. Complete information will be computed and reported in conjunction with your 2021 form 1099-DIV.

The qualifying percentage of the Fund’s ordinary income dividends for the purpose of the corporate dividends received deduction was 100.0%.

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Statement Regarding Liquidity Risk Management Program

As required by law, the Fund has adopted and implemented a liquidity risk management program (the “Program”) that is designed to assess and manage liquidity risk. Liquidity risk is the risk that the Fund could not meet requests to redeem its shares without significant dilution of remaining investors’ interests in the Fund. The Fund’s Board of Trustees designated a liquidity risk management committee (the “Committee”) consisting of employees of Amundi Asset Management US, Inc. (the “Adviser”) to administer the Program.

The Committee provided the Board of Trustees with a report that addressed the operation of the Program and assessed its adequacy and effectiveness of implementation (the “Report”). The Report covered the period from January 1, 2020 through December 31, 2020 (the “Reporting Period”).

The Report confirmed that, throughout the Reporting Period, the Committee had monitored the Fund’s portfolio liquidity and liquidity risk on an ongoing basis, as described in the Program and in Board reporting throughout the Reporting Period.

The Report discussed the Committee’s annual review of the Program, which addressed, among other things, the following elements of the Program:

The Committee reviewed the Fund’s investment strategy and liquidity of portfolio investments during both normal and reasonably foreseeable stressed conditions. The Committee noted that the Fund’s investment strategy continues to be appropriate for an open-end fund, taking into account, among other things, whether and to what extent the Fund held less liquid and illiquid assets and the extent to which any such investments affected the Fund’s ability to meet redemption requests. In managing and reviewing the Fund’s liquidity risk, the Committee also considered the extent to which the Fund’s investment strategy involves a relatively concentrated portfolio or large positions in particular issuers, the extent to which the Fund uses borrowing for investment purposes, and the extent to which the Fund uses derivatives (including for hedging purposes). The Committee also reviewed the Fund’s short-term and long-term cash flow projections during both normal and reasonably foreseeable stressed conditions. In assessing the Fund’s cash flow projections, the Committee considered, among other factors, historical net redemption activity, redemption policies, ownership concentration, distribution channels, and the degree of certainty associated with the Fund’s short-term and long-term cash flow projections. The Committee also considered the Fund’s

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holdings of cash and cash equivalents, as well as borrowing arrangements and other funding sources, including, if applicable, the Fund’s participation in a credit facility, as components of the Fund’s ability to meet redemption requests. The Fund has adopted an in-kind redemption policy which may be utilized to meet larger redemption requests.

The Committee reviewed the Program’s liquidity classification methodology for categorizing the Fund’s investments into one of four liquidity buckets. In reviewing the Fund’s investments, the Committee considered, among other factors, whether trading varying portions of a position in a particular portfolio investment or asset class in sizes the Fund would reasonably anticipate trading, would be reasonably expected to significantly affect liquidity.

The Committee performed an analysis to determine whether the Fund is required to maintain a Highly Liquid Investment Minimum, and determined that no such minimum is required because the Fund primarily holds highly liquid investments.

The Report stated that the Committee concluded the Program operates adequately and effectively, in all material respects, to assess and manage the Fund’s liquidity risk throughout the Reporting Period.

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Approval of Renewal of Investment Management Agreement

Amundi Asset Management US, Inc. (“Amundi US”) serves as the investment adviser to Pioneer Mid Cap Value Fund (the “Fund”) pursuant to an investment management agreement between Amundi US and the Fund. In order for Amundi US to remain the investment adviser of the Fund, the Trustees of the Fund, including a majority of the Fund’s Independent Trustees, must determine annually whether to renew the investment management agreement for the Fund.

The contract review process began in January 2021 as the Trustees of the Fund agreed on, among other things, an overall approach and timeline for the process. Contract review materials were provided to the Trustees in March 2021, July 2021 and September 2021. In addition, the Trustees reviewed and discussed the Fund’s performance at regularly scheduled meetings throughout the year, and took into account other information related to the Fund provided to the Trustees at regularly scheduled meetings, in connection with the review of the Fund’s investment management agreement.

In March 2021, the Trustees, among other things, discussed the memorandum provided by Fund counsel that summarized the legal standards and other considerations that are relevant to the Trustees in their deliberations regarding the renewal of the investment management agreement, and reviewed and discussed 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. In July 2021, the Trustees, among other things, reviewed the Fund’s management fees and total expense ratios, the financial statements of Amundi US and its parent companies, profitability analyses provided by Amundi US, and analyses from Amundi US as to possible economies of scale. The Trustees also reviewed the profitability of the institutional business of Amundi US as compared to that of Amundi US’s fund management business, and considered the differences between the fees and expenses of the Fund and the fees and expenses of Amundi US’s institutional accounts, as well as the different services provided by Amundi US to the Fund and to the institutional accounts. The Trustees further considered contract review materials, including additional materials received in response to the Trustees’ request, in September 2021.

At a meeting held on September 21, 2021, based on their evaluation of the information provided by Amundi US and third parties, the Trustees of the Fund, including the Independent Trustees voting separately, unanimously approved the renewal of the investment management agreement for another

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year. In approving the renewal of the investment management agreement, 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 determining to approve the renewal of the agreement.

Nature, Extent and Quality of Services

The Trustees considered the nature, extent and quality of the services that had been provided by Amundi US to the Fund, taking into account the investment objective and strategy of the Fund. The Trustees also reviewed Amundi US’s investment approach for the Fund and its research process. The Trustees considered the resources of Amundi US and the personnel of Amundi US who provide investment management services to the Fund. They also reviewed the amount of non-Fund assets managed by the portfolio managers of the Fund. They considered the non-investment resources and personnel of Amundi US that are involved in Amundi US’s services to the Fund, including Amundi US’s compliance, risk management, and legal resources and personnel. The Trustees noted the substantial attention and high priority given by Amundi US’s senior management to the Pioneer Fund complex. The Trustees considered the effectiveness of Amundi US’s business continuity plan in response to the COVID-19 pandemic.

The Trustees considered that Amundi US 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 the Fund’s business management and operations. The Trustees also considered that, as administrator, Amundi US is responsible for the administration of the Fund’s business and other affairs. The Trustees considered Amundi US’s oversight of the process for transitioning custodian, transfer agent and sub-administration services to new service providers. The Trustees considered that the Fund reimburses Amundi US its pro rata share of Amundi US’s costs of providing administration services to the Pioneer Funds.

Based on these considerations, the Trustees concluded that the nature, extent and quality of services that had been provided by Amundi US to the Fund were satisfactory and consistent with the terms of the investment management agreement.

Performance of the Fund.

In considering the Fund’s performance, the Trustees regularly review and discuss throughout the year data prepared by Amundi US and information comparing the Fund’s performance with the performance of its peer group of funds, as classified by Morningstar, Inc. (Morningstar), and with the

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performance of the Fund’s benchmark index. They also discuss the Fund’s performance with Amundi US on a regular basis. The Trustees’ regular reviews and discussions were factored into the Trustees’ deliberations concerning the renewal of the investment management agreement.

Management Fee and Expenses

The Trustees considered information showing the fees and expenses of the Fund in comparison to the management fees 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. The peer group comparisons referred to below are organized in quintiles. Each quintile represents one-fifth of the peer group. In all peer group comparisons referred to below, first quintile is most favorable to the Fund’s shareowners. The Trustees noted that they separately review and consider the impact of the Fund’s transfer agency and Fund- and Amundi US-paid expenses for 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 for the most recent fiscal year was in the first quintile relative to the management fees paid by other funds in its Morningstar category for the comparable period. The Trustees noted the impact of the Fund’s performance on the management fee paid by the Fund. The Trustees also considered the breakpoints in the management fee schedule and the reduced fee rates above certain asset levels. The Trustees considered that the expense ratio of the Fund’s Class Y shares for the most recent fiscal year was in the first quintile relative to its Strategic Insight peer group for the comparable period. The Trustees considered that the expense ratio of the Fund’s Class A shares for the most recent fiscal year was in the first quintile relative to its Strategic Insight peer group for the comparable period.

The Trustees reviewed management fees charged by Amundi US to institutional and other clients, including publicly offered European funds sponsored by Amundi US’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 US’s costs in providing services to the Fund and Amundi US’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 US’s client accounts, the Trustees took into account the respective demands, resources and complexity associated with

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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 the investment management and administration agreements with the Fund, Amundi US performs 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 is subject. The Trustees also considered the entrepreneurial risks associated with Amundi US’s management of the Fund.

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

Profitability

The Trustees considered information provided by Amundi US regarding the profitability of Amundi US with respect to the advisory services provided by Amundi US to the Fund, including the methodology used by Amundi US in allocating certain of its costs to the management of the Fund. The Trustees also considered Amundi US’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 US from non-fund businesses. The Trustees considered Amundi US’s profit margins 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 US’s profitability with respect to the management of the Fund was not unreasonable.

Economies of Scale

The Trustees considered Amundi US’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 noted the breakpoints in the management fee schedule. 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 US in research and analytical capabilities and Amundi US’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.

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Other Benefits

The Trustees considered the other benefits that Amundi US 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 investment management agreement, for services provided by Amundi US and its affiliates. The Trustees further considered the revenues and profitability of Amundi US’s businesses other than the Fund business. To the extent applicable, the Trustees also considered the benefits to the Fund and to Amundi US 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 Amundi US is the principal U.S. asset management business of Amundi, which is one of the largest asset managers globally. Amundi’s worldwide asset management business manages over $2.12 trillion in assets (including the Pioneer Funds). The Trustees considered that Amundi US’s relationship with Amundi creates potential opportunities for Amundi US and Amundi that derive from Amundi US’s relationships with the Fund, including Amundi’s ability to market the services of Amundi US globally. The Trustees noted that Amundi US has access to additional research and portfolio management capabilities as a result of its relationship with Amundi and Amundi’s enhanced global presence that may contribute to an increase in the resources available to Amundi US. The Trustees considered that Amundi US and the Fund 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 US 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 investment management agreement for the Fund, including the fees payable thereunder, was fair and reasonable and voted to approve the proposed renewal of the investment management agreement.

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Trustees, Officers and Service Providers

Investment Adviser and Administrator

Amundi Asset Management US, Inc.

Custodian and Sub-Administrator
Brown Brothers Harriman & Co.*

Independent Registered Public Accounting Firm
Ernst & Young LLP

Principal Underwriter
Amundi Distributor US, Inc.

Legal Counsel
Morgan, Lewis & Bockius LLP

Transfer Agent
DST Asset Manager Solutions, 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.amundi.com/us. This information is also available on the Securities and Exchange Commission’s web site at www.sec.gov.

Trustees and Officers

The Fund’s Trustees and officers are listed below, together with their principal occupations and other directorships they have held during at least the past five years. Trustees who are interested persons of the Fund within the meaning of the 1940 Act are referred to as Interested Trustees. Trustees who are not interested persons of the Fund are referred to as Independent Trustees. Each of the Trustees serves as a Trustee of each of the 49 U.S. registered investment portfolios for which Amundi US serves as investment adviser (the “Pioneer Funds”). The address for all Trustees and all officers of the Fund is 60 State Street, Boston, Massachusetts 02109.

The Statement of Additional Information of the Fund includes additional information about the Trustees and is available, without charge, upon request, by calling 1-800-225-6292.

Note to shareowners: The Bank of New York Mellon (BNY Mellon) became the Fund's custodian and sub-administrator effective November 22, 2021.

Note to shareowners: BNY Mellon Investment Servicing (US), Inc. became the Fund's transfer agent effective November 22, 2021.

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Independent Trustees

Name, Age and			Other Directorships
Position Held With	Term of Office and		Held by Trustee During At
the Fund	Length of Service	Principal Occupation(s) During At Least The Past Five Years	Least The Past Five Years
Thomas J. Perna (71)	Trustee since 2006.	Private investor (2004 – 2008 and 2013 – present); Chairman	Director, Broadridge Financial
Chairman of the Board	Serves until a successor	(2008 – 2013) and Chief Executive Officer (2008 – 2012), Quadriserv, Inc.	Solutions, Inc. (investor
and Trustee	trustee is elected	(technology products for securities lending industry); and Senior Executive	communications and securities
	or earlier retirement	Vice President, The Bank of New York (financial and securities services)	processing provider for financial
	or removal.	(1986 – 2004)	services industry) (2009 – present);
			Director, Quadriserv, Inc. (2005 –
			2013); and Commissioner, New
			Jersey State Civil Service
			Commission (2011 – 2015)
John E. Baumgardner, Jr. (70)	Trustee since 2019.	Of Counsel (2019 – present), Partner (1983-2018), Sullivan & Cromwell	Chairman, The Lakeville Journal
Trustee	Serves until a successor	LLP (law firm).	Company, LLC, (privately-held
	trustee is elected		community newspaper group)
	or earlier retirement		(2015-present)
	or removal.
Diane Durnin (64)	Trustee since 2019.	Managing Director - Head of Product Strategy and Development, BNY	None
Trustee	Serves until a successor	Mellon Investment Management (investment management firm)
	trustee is elected	(2012-2018); Vice Chairman – The Dreyfus Corporation (2005 – 2018):
	or earlier retirement	Executive Vice President Head of Product, BNY Mellon Investment
	or removal.	Management (2007-2012); Executive Director- Product Strategy, Mellon
		Asset Management (2005-2007); Executive Vice President Head of
		Products, Marketing and Client Service, Dreyfus Corporation (investment
		management firm) (2000-2005); and Senior Vice President Strategic
		Product and Business Development, Dreyfus Corporation (1994-2000)

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Independent Trustees (continued)

Name, Age and			Other Directorships
Position Held With	Term of Office and		Held by Trustee During At
the Fund	Length of Service	Principal Occupation(s) During At Least The Past Five Years	Least The Past Five Years
Benjamin M. Friedman (77)	Trustee since 2008.	William Joseph Maier Professor of Political Economy, Harvard	Trustee, Mellon Institutional Funds
Trustee	Serves until a successor	University (1972 – present)	Investment Trust and Mellon
	trustee is elected or		Institutional Funds Master Portfolio
	earlier retirement		(oversaw 17 portfolios in fund
	or removal.		complex) (1989 - 2008)
Craig C. MacKay (58)	Trustee since 2021.	Partner, England & Company, LLC (advisory firm) (2012 – present);	Board Member of Carver Bancorp,
Trustee	Serves until a successor	Group Head – Leveraged Finance Distribution, Oppenheimer & Company	Inc. (holding company) and Carver
	trustee is elected or	(investment bank) (2006 – 2012); Group Head – Private Finance & High	Federal Savings Bank, NA (2017 –
	earlier retirement	Yield Capital Markets Origination, SunTrust Robinson Humphrey	present); Advisory Council Member,
	or removal.	(investment bank) (2003 – 2006); and Founder and Chief Executive	MasterShares ETF (2016 – 2017);
		Officer, HNY Associates, LLC (investment bank) (1996 – 2003)	Advisory Council Member, The Deal
			(financial market information
			publisher) (2015 – 2016); Board
			Co-Chairman and Chief Executive
			Officer, Danis Transportation
			Company (privately-owned
			commercial carrier) (2000 – 2003);
			Board Member and Chief Financial
			Officer, Customer Access Resources
			(privately-owned teleservices
			company) (1998 – 2000); Board
			Member, Federation of Protestant
			Welfare Agencies (human services
			agency) (1993 – present); and
			Board Treasurer, Harlem Dowling
			Westside Center (foster care
			agency) (1999 – 2018)

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Name, Age and			Other Directorships
Position Held With	Term of Office and		Held by Trustee During At
the Fund	Length of Service	Principal Occupation(s) During At Least The Past Five Years	Least The Past Five Years
Lorraine H. Monchak (65)	Trustee since 2017.	Chief Investment Officer, 1199 SEIU Funds (healthcare workers union	None
Trustee	(Advisory Trustee from	pension funds) (2001 – present); Vice President – International Investments
	2014 - 2017). Serves	Group, American International Group, Inc. (insurance company)
	until a successor trustee	(1993 – 2001); Vice President – Corporate Finance and Treasury Group,
	is elected or earlier	Citibank, N.A. (1980 – 1986 and 1990 – 1993); Vice President –
	retirement or removal.	Asset/Liability Management Group, Federal Farm Funding Corporation
		(government-sponsored issuer of debt securities) (1988 – 1990); Mortgage
		Strategies Group, Shearson Lehman Hutton, Inc. (investment bank)
		(1987 – 1988); and Mortgage Strategies Group, Drexel Burnham Lambert,
		Ltd. (investment bank) (1986 – 1987)
Marguerite A. Piret (73)	Trustee since 1990.	Chief Financial Officer, American Ag Energy, Inc. (controlled environment	Director of New America High
Trustee	Serves until a successor	and agriculture company) (2016 – present); and President and Chief	Income Fund, Inc. (closed-end
	trustee is elected or	Executive Officer, Metric Financial Inc. (formerly known as Newbury Piret	investment company) (2004 –
	earlier retirement	Company) (investment banking firm) (1981 – 2019)	present); and Member, Board of
	or removal.		Governors, Investment Company
			Institute (2000 – 2006)
Fred J. Ricciardi (74)	Trustee since 2014.	Private investor (2020 – present); Consultant (investment company	None
Trustee	Serves until a successor	services) (2012 – 2020); Executive Vice President, BNY Mellon (financial and
	trustee is elected or	investment company services) (1969 – 2012); Director, BNY International
	earlier retirement	Financing Corp. (financial services) (2002 – 2012); Director, Mellon Overseas
	or removal.	Investment Corp. (financial services) (2009 – 2012); Director, Financial
		Models (technology) (2005-2007); Director, BNY Hamilton Funds, Ireland
		(offshore investment companies) (2004-2007); Chairman/Director, AIB/BNY
		Securities Services, Ltd., Ireland (financial services) (1999-2006); and
		Chairman, BNY Alternative Investment Services, Inc. (financial services)
		(2005-2007)

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Interested Trustees

Name, Age and			Other Directorships
Position Held With	Term of Office and		Held by Trustee During At
the Fund	Length of Service	Principal Occupation(s) During At Least The Past Five Years	Least The Past Five Years
Lisa M. Jones (59)*	Trustee since 2017.	Director, CEO and President of Amundi US, Inc. (investment management	None
Trustee, President and	Serves until a successor	firm) (since September 2014); Director, CEO and President of Amundi Asset
Chief Executive Officer	trustee is elected or	Management US, Inc. (since September 2014); Director, CEO and President
	earlier retirement	of Amundi Distributor US, Inc. (since September 2014); Director, CEO and
	or removal	President of Amundi Asset Management US, Inc. (since September 2014);
		Chair, Amundi US, Inc., Amundi Distributor US, Inc. and Amundi Asset
		Management US, Inc. (September 2014 – 2018); Managing Director,
		Morgan Stanley Investment Management (investment management firm)
		(2010 – 2013); Director of Institutional Business, CEO of International,
		Eaton Vance Management (investment management firm) (2005 – 2010);
		and Director of Amundi Holdings US, Inc. (since 2017)
Kenneth J. Taubes (63)*	Trustee since 2014.	Director and Executive Vice President (since 2008) and Chief Investment	None
Trustee	Serves until a successor	Officer, U.S. (since 2010) of Amundi US, Inc. (investment management
	trustee is elected or	firm); Director and Executive Vice President and Chief Investment Officer,
	earlier retirement	U.S. of Amundi US (since 2008); Executive Vice President and Chief
	or removal	Investment Officer, U.S. of Amundi Asset Management US, Inc. (since 2009);
		Portfolio Manager of Amundi US (since 1999); and Director of Amundi
		Holdings US, Inc. (since 2017)

Ms. Jones and Mr. Taubes are Interested Trustees because they are officers or directors of the Fund’s investment adviser and certain of its affiliates.

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Fund Officers

Name, Age and			Other Directorships
Position Held With	Term of Office and		Held by Officer During At
the Fund	Length of Service	Principal Occupation(s) During At Least The Past Five Years	Least The Past Five Years
Christopher J. Kelley (56)	Since 2003. Serves at	Vice President and Associate General Counsel of Amundi US since January	None
Secretary and Chief	the discretion of	2008; Secretary and Chief Legal Officer of all of the Pioneer Funds since
Legal Officer	the Board	June 2010; Assistant Secretary of all of the Pioneer Funds from September
		2003 to May 2010; and Vice President and Senior Counsel of Amundi US
		from July 2002 to December 2007
Thomas Reyes (58)	Since 2010. Serves at	Assistant General Counsel of Amundi US since May 2013 and Assistant	None
Assistant Secretary	the discretion of	Secretary of all the Pioneer Funds since June 2010; and Counsel of
	the Board	Amundi US from June 2007 to May 2013
Anthony J. Koenig, Jr. (57)	Since 2021. Serves at	Senior Vice President – Fund Treasury of Amundi US; Treasurer of all of	None
Treasurer and Chief	the discretion of	the Pioneer Funds since May 2021; Assistant Treasurer of all of the Pioneer
Financial and	the Board	Funds from January 2021 to May 2021; and Chief of Staff, US Investment
Accounting Officer		Management of Amundi US from May 2008 to January 2021
Luis I. Presutti (56)	Since 2000. Serves at	Director – Fund Treasury of Amundi US since 1999; and Assistant Treasurer	None
Assistant Treasurer	the discretion of	of all of the Pioneer Funds since 1999
	the Board
Gary Sullivan (63)	Since 2002. Serves at	Senior Manager – Fund Treasury of Amundi US since 2012; and Assistant	None
Assistant Treasurer	the discretion of	Treasurer of all of the Pioneer Funds since 2002
	the Board
Antonio Furtado (39)	Since 2020. Serves at	Fund Oversight Manager – Fund Treasury of Amundi US since 2020;	None
Assistant Treasurer	the discretion of	Assistant Treasurer of all of the Pioneer Funds since 2020; and Senior Fund
	the Board	Treasury Analyst from 2012 - 2020

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Fund Officers (continued)

Name, Age and			Other Directorships
Position Held With	Term of Office and		Held by Officer During At
the Fund	Length of Service	Principal Occupation(s) During At Least The Past Five Years	Least The Past Five Years
Michael Melnick (50)	Since July 2021.	Vice President - Deputy Fund Treasurer of Amundi US since May 2021;	None
Assistant Treasurer	Serves at the	Assistant Treasurer of all of the Pioneer Funds since July 2021; Director of
	discretion of the Board	Regulatory Reporting of Amundi US from 2001 – 2021; and Director of
		Tax of Amundi US from 2000 - 2001
John Malone (50)	Since 2018. Serves at	Managing Director, Chief Compliance Officer of Amundi US Asset	None
Chief Compliance Officer	the discretion of	Management; Amundi Asset Management US, Inc.; and the Pioneer Funds
	the Board	since September 2018; and Chief Compliance Officer of Amundi Distributor
		US, Inc. since January 2014.
Kelly O’Donnell (50)	Since 2006. Serves at	Vice President – Amundi Asset Management; and Anti-Money Laundering	None
Anti-Money Laundering	the discretion of	Officer of all the Pioneer Funds since 2006
Officer	the Board

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How to Contact Amundi

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^SMfor automated fund yields, prices,
account information and transactions	1-800-225-4321

Retirement plans information	1-800-622-0176

Write to us:

Amundi
P.O. Box 9897
Providence, RI 02940-8097

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

Our internet e-mail address	us.askamundi@amundi.com
(for general questions about Amundi only)

Visit our web site: www.amundi.com/us

This report must be preceded or accompanied by a prospectus.

The Fund files a complete schedule of portfolio holdings with the Securities and Exchange Commission for the first and third quarters of each fiscal year as an exhibit to its reports on Form N-PORT. Shareholders may view the filed Form N-PORT by visiting the Commission’s web site at https://www.sec.gov.

Amundi Asset Management US, Inc.
60 State Street
Boston, MA 02109
www.amundi.com/us

Securities offered through Amundi Distributor US, Inc.,
60 State Street, Boston, MA 02109
Underwriter of Pioneer Mutual Funds, Member SIPC
© 2021 Amundi Asset Management US, Inc. 19443-15-1221

ITEM 2. CODE OF ETHICS.

(a) Disclose whether, as of the end of the period covered by the report, the registrant has adopted a code of ethics that applies to the registrant’s principal executive officer, principal financial officer, principal accounting officer or controller, or persons performing similar functions, regardless of whether these individuals are employed by the registrant or a third party. If the registrant has not adopted such a code of ethics, explain why it has not done so.

The registrant has adopted, as of the end of the period covered by this report, a code of ethics that applies to the registrant’s principal executive officer, principal financial officer, principal accounting officer and controller.

(b) For purposes of this Item, the term “code of ethics” means written standards that are reasonably designed to deter wrongdoing and to promote:

(1) Honest and ethical conduct, including the ethical handling of actual or apparent conflicts of interest between personal and professional relationships;

(2) Full, fair, accurate, timely, and understandable disclosure in reports and documents that a registrant files with, or submits to, the Commission and in other public communications made by the registrant;

(3) Compliance with applicable governmental laws, rules, and regulations;

(4) The prompt internal reporting of violations of the code to an appropriate person or persons identified in the code; and

(5) Accountability for adherence to the code.

(c) The registrant must briefly describe the nature of any amendment, during the period covered by the report, to a provision of its code of ethics that applies to the registrant’s principal executive officer, principal financial officer, principal accounting officer or controller, or persons performing similar functions, regardless of whether these individuals are employed by the registrant or a third party, and that relates to any element of the code of ethics definition enumerated in paragraph (b) of this Item. The registrant must file a copy of any such amendment as an exhibit pursuant to Item 10(a), unless the registrant has elected to satisfy paragraph (f) of this Item by posting its code of ethics on its website pursuant to paragraph (f)(2) of this Item, or by undertaking to provide its code of ethics to any person without charge, upon request, pursuant to paragraph (f)(3) of this Item.

The registrant has made no amendments to the code of ethics during the period covered by this report.

(d) If the registrant has, during the period covered by the report, granted a waiver, including an implicit waiver, from a provision of the code of ethics to the registrant’s principal executive officer, principal financial officer, principal accounting officer or controller, or persons performing similar functions, regardless of whether these individuals are employed by the registrant or a third party, that relates to one or more of the items set forth in paragraph (b) of this Item, the registrant must briefly describe the nature of the waiver, the name of the person to whom the waiver was granted, and the date of the waiver.

Not applicable.

(e) If the registrant intends to satisfy the disclosure requirement under paragraph (c) or (d) of this Item regarding an amendment to, or a waiver from, a provision of its code of ethics that applies to the registrant’s principal executive officer, principal financial officer, principal accounting officer or controller, or persons performing similar functions and that relates to any element of the code of ethics definition

enumerated in paragraph (b) of this Item by posting such information on its Internet website, disclose the registrant’s Internet address and such intention.

Not applicable.

(f) The registrant must:

(1) File with the Commission, pursuant to Item 12(a)(1), a copy of its code of ethics that applies to the registrant’s principal executive officer, principal financial officer, principal accounting officer or controller, or persons performing similar functions, as an exhibit to its annual report on this Form N-CSR (see attachment);

(2) Post the text of such code of ethics on its Internet website and disclose, in its most recent report on this Form N-CSR, its Internet address and the fact that it has posted such code of ethics on its Internet website; or

(3) Undertake in its most recent report on this Form N-CSR to provide to any person without charge, upon request, a copy of such code of ethics and explain the manner in which such request may be made. See Item 10(2)

ITEM 3. AUDIT COMMITTEE FINANCIAL EXPERT.

(a) (1) Disclose that the registrant’s board of trustees has determined that the registrant either:

(i) Has at least one audit committee financial expert serving on its audit committee; or

(ii) Does not have an audit committee financial expert serving on its audit committee.

The registrant’s Board of Trustees has determined that the registrant has at least one audit committee financial expert.

(2) If the registrant provides the disclosure required by paragraph (a)(1)(i) of this Item, it must disclose the name of the audit committee financial expert and whether that person is “independent.” In order to be considered “independent” for purposes of this Item, a member of an audit committee may not, other than in his or her capacity as a member of the audit committee, the board of trustees, or any other board committee:

(i) Accept directly or indirectly any consulting, advisory, or other compensatory fee from the issuer; or

(ii) Be an “interested person” of the investment company as defined in Section 2(a)(19) of the Act (15 U.S.C. 80a-2(a)(19)).

Mr. Fred J. Ricciardi, an independent trustee, is such an audit committee financial expert.

(3) If the registrant provides the disclosure required by paragraph (a)(1) (ii) of this Item, it must explain why it does not have an audit committee financial expert.

Not applicable.

ITEM 4. PRINCIPAL ACCOUNTANT FEES AND SERVICES.

(a) Disclose, under the caption AUDIT FEES, the aggregate fees billed for each of the last two fiscal years for professional services rendered by the principal accountant for the audit of the registrant’s annual financial statements or services that are normally provided by the accountant in connection with statutory and regulatory filings or engagements for those fiscal years.

The audit fees for the Fund were $23,460 payable to Ernst & Young LLP for the year ended October 31, 2021 and $23,460 for the year ended October 31, 2020.

(b) Disclose, under the caption AUDIT-RELATED FEES, the aggregate fees billed in each of the last two fiscal years for assurance and related services by the principal accountant that are reasonably related to the performance of the audit of the registrant’s financial statements and are not reported under paragraph (a) of this Item. Registrants shall describe the nature of the services comprising the fees disclosed under this category.

There were no audit-related services in 2021 or 2020.

(c) Disclose, under the caption TAX FEES, the aggregate fees billed in each of the last two fiscal years for professional services rendered by the principal accountant for tax compliance, tax advice, and tax planning. Registrants shall describe the nature of the services comprising the fees disclosed under this category.

The Fund paid aggregate non-audit fees to Ernst & Young LLP for tax services of $8,189 and $8,189 during the fiscal years ended October 31, 2021 and 2020, respectively.

(d) Disclose, under the caption ALL OTHER FEES, the aggregate fees billed in each of the last two fiscal years for products and services provided by the principal accountant, other than the services reported in paragraphs (a) through (c) of this Item. Registrants shall describe the nature of the services comprising the fees disclosed under this category.

There were no other fees in 2021 or 2020.

(e) (1) Disclose the audit committee’s pre-approval policies and procedures described in paragraph (c)(7) of Rule 2-01 of Regulation S-X.

PIONEER FUNDS

APPROVAL OF AUDIT, AUDIT-RELATED, TAX AND OTHER SERVICES

PROVIDED BY THE INDEPENDENT AUDITOR

SECTION I - POLICY PURPOSE AND APPLICABILITY

The Pioneer Funds recognize the importance of maintaining the independence of their outside auditors. Maintaining independence is a shared responsibility involving Amundi Asset Management US, Inc., the audit committee and the independent auditors.

The Funds recognize that a Fund’s independent auditors: 1) possess knowledge of the Funds, 2) are able to incorporate certain services into the scope of the audit, thereby avoiding redundant work, cost and disruption of Fund personnel and processes, and 3) have expertise that has value to the Funds. As a result, there are situations where it is desirable to use the Fund’s independent auditors for services in addition to the annual audit and where the potential for conflicts of interests are minimal. Consequently, this policy, which is intended to comply with Rule 210.2-01(C)(7), sets forth guidelines and procedures to be followed by the Funds when retaining the independent audit firm to perform audit, audit-related tax and other services under those circumstances, while also maintaining independence.

Approval of a service in accordance with this policy for a Fund shall also constitute approval for any other Fund whose pre-approval is required pursuant to Rule 210.2-01(c)(7)(ii).

In addition to the procedures set forth in this policy, any non-audit services that may be provided consistently with Rule 210.2-01 may be approved by the Audit Committee itself and any pre-approval that may be waived in accordance with Rule 210.2-01(c)(7)(i)(C) is hereby waived.

Selection of a Fund’s independent auditors and their compensation shall be determined by the Audit Committee and shall not be subject to this policy.


SECTION II - POLICY

SERVICE CATEGORY	SERVICE CATEGORY DESCRIPTION		SPECIFIC PRE-APPROVED SERVICE SUBCATEGORIES

I. AUDIT SERVICES	Services that are directly		o Accounting research assistance
	related to performing the		o SEC consultation, registration
	independent audit of the Funds		statements, and reporting
			o Tax accrual related matters
			o Implementation of new accounting standards
			o Compliance letters (e.g. rating agency letters)
			o Regulatory reviews and assistance
			regarding financial matters
			o Semi-annual reviews (if requested)
			o Comfort letters for closed end offerings
II. AUDIT-RELATED	Services which are not		o AICPA attest and agreed-upon procedures
SERVICES	prohibited under Rule		o Technology control assessments
	210.2-01(C)(4) (the “Rule”)		o Financial reporting control assessments
	and are related extensions of		o Enterprise security architecture
	the audit services support the		assessment
	audit, or use the knowledge/expertise
	gained from the audit procedures as a
	foundation to complete the project.
	In most cases, if the Audit-Related
	Services are not performed by the
	Audit firm, the scope of the Audit
	Services would likely increase.
	The Services are typically well-defined
	and governed by accounting
	professional standards (AICPA,
	SEC, etc.)

AUDIT COMMITTEE APPROVAL POLICY		AUDIT COMMITTEE REPORTING POLICY
o “One-time” pre-approval		o A summary of all such
for the audit period for all		services and related fees
pre-approved specific service		reported at each regularly
subcategories. Approval of the		scheduled Audit Committee
independent auditors as		meeting.
auditors for a Fund shall
constitute pre approval for
these services.

o “One-time” pre-approval		o A summary of all such
for the fund fiscal year within		services and related fees
a specified dollar limit		(including comparison to
for all pre-approved		specified dollar limits)
specific service subcategories		reported quarterly.

o Specific approval is
needed to exceed the
pre-approved dollar limit for
these services (see general
Audit Committee approval policy
below for details on obtaining
specific approvals)

o Specific approval is
needed to use the Fund’s
auditors for Audit-Related
Services not denoted as
“pre-approved”, or
to add a specific service
subcategory as “pre-approved”

SECTION III - POLICY DETAIL, CONTINUED


SERVICE CATEGORY	SERVICE CATEGORY DESCRIPTION	SPECIFIC PRE-APPROVED SERVICE
		SUBCATEGORIES
III. TAX SERVICES	Services which are not	o Tax planning and support
	prohibited by the Rule,	o Tax controversy assistance
	if an officer of the Fund	o Tax compliance, tax returns, excise
	determines that using the	tax returns and support
	Fund’s auditor to provide	o Tax opinions
	these services creates
	significant synergy in
	the form of efficiency,
	minimized disruption, or
	the ability to maintain a
	desired level of
	confidentiality.


AUDIT COMMITTEE APPROVAL POLICY	AUDIT COMMITTEE REPORTING POLICY
o “One-time” pre-approval	o A summary of
for the fund fiscal year	all such services and
within a specified dollar limit	related fees
	(including comparison
	to specified dollar
	limits) reported
	quarterly.

o Specific approval is
needed to exceed the
pre-approved dollar limits for
these services (see general
Audit Committee approval policy
below for details on obtaining
specific approvals)

o Specific approval is
needed to use the Fund’s
auditors for tax services not
denoted as pre-approved, or to
add a specific service subcategory as
“pre-approved”

SECTION III - POLICY DETAIL, CONTINUED


SERVICE CATEGORY	SERVICE CATEGORY DESCRIPTION	SPECIFIC PRE-APPROVED SERVICE
		SUBCATEGORIES
IV. OTHER SERVICES	Services which are not	o Business Risk Management support
	prohibited by the Rule,	o Other control and regulatory
A. SYNERGISTIC,	if an officer of the Fund	compliance projects
UNIQUE QUALIFICATIONS	determines that using the
	Fund’s auditor to provide
	these services creates
	significant synergy in
	the form of efficiency,
	minimized disruption,
	the ability to maintain a
	desired level of
	confidentiality, or where
	the Fund’s auditors
	posses unique or superior
	qualifications to provide
	these services, resulting
	in superior value and
	results for the Fund.


AUDIT COMMITTEE APPROVAL POLICY	AUDIT COMMITTEE REPORTING POLICY
o “One-time” pre-approval	o A summary of
for the fund fiscal year within	all such services and
a specified dollar limit	related fees
	(including comparison
	to specified dollar
	limits) reported
	quarterly.
o Specific approval is
needed to exceed the
pre-approved dollar limits for
these services (see general
Audit Committee approval policy
below for details on obtaining
specific approvals)

o Specific approval is
needed to use the Fund’s
auditors for “Synergistic” or
“Unique Qualifications” Other
Services not denoted as
pre-approved to the left, or to
add a specific service
subcategory as “pre-approved”

SECTION III - POLICY DETAIL, CONTINUED


SERVICE CATEGORY	SERVICE CATEGORY DESCRIPTION	SPECIFIC PROHIBITED SERVICE
		SUBCATEGORIES
PROHIBITED SERVICES	Services which result	1. Bookkeeping or other services
	in the auditors losing	related to the accounting records or
	independence status	financial statements of the audit
	under the Rule.	client*
		2. Financial information systems design
		and implementation*
		3. Appraisal or valuation services,
		fairness* opinions, or
		contribution-in-kind reports
		4. Actuarial services (i.e., setting
		actuarial reserves versus actuarial
		audit work)*
		5. Internal audit outsourcing services*
		6. Management functions or human
		resources
		7. Broker or dealer, investment
		advisor, or investment banking services
		8. Legal services and expert services
		unrelated to the audit
		9. Any other service that the Public
		Company Accounting Oversight Board
		determines, by regulation, is
		impermissible


AUDIT COMMITTEE APPROVAL POLICY	AUDIT COMMITTEE REPORTING POLICY
o These services are not to be	o A summary of all
performed with the exception of the(*)	services and related
services that may be permitted	fees reported at each
if they would not be subject to audit	regularly scheduled
procedures at the audit client (as	Audit Committee meeting
defined in rule 2-01(f)(4)) level	will serve as continual
the firm providing the service.	confirmation that has
	not provided any
	restricted services.

GENERAL AUDIT COMMITTEE APPROVAL POLICY:

o For all projects, the officers of the Funds and the Fund’s auditors will each make an assessment to determine that any proposed projects will not impair independence.

o Potential services will be classified into the four non-restricted service categories and the “Approval of Audit, Audit-Related, Tax and Other Services” Policy above will be applied. Any services outside the specific pre-approved service subcategories set forth above must be specifically approved by the Audit Committee.

o At least quarterly, the Audit Committee shall review a report summarizing the services by service category, including fees, provided by the Audit firm as set forth in the above policy.

(2) Disclose the percentage of services described in each of paragraphs (b) through (d) of this Item that were approved by the audit committee pursuant to paragraph (c)(7)(i)(C) of Rule 2-01 of Regulation S-X.

Non-Audit Services

Beginning with non-audit service contracts entered into on or after May 6, 2003, the effective date of the

new SEC pre-approval rules, the Fund's audit committee is required to pre-approve services to

affiliates defined by SEC rules to the extent that the services are determined to have a direct impact on the operations or financial reporting of the Fund. For the years ended October 31, 2021 and 2020, there were no services provided to an affiliate that required the Fund's audit committee pre-approval.

(f) If greater than 50 percent, disclose the percentage of hours expended on the principal accountants engagement to audit the registrant’s financial statements for the most recent fiscal year that were attributed to work performed by persons other than the principal accountant’s full-time, permanent employees.

N/A

(g) Disclose the aggregate non-audit fees billed by the registrants accountant for services rendered to the registrant, and rendered to the registrants investment adviser (not including any sub-adviser whose role is primarily portfolio management and is subcontracted with or overseen by another investment adviser), and any entity controlling, controlled by, or under common control with the adviser that provides ongoing services to the registrant for each of the last two fiscal years of the registrant.

The Fund paid aggregate non-audit fees to Ernst & Young LLP for tax services of $8,189 and $8,189 during the fiscal years ended October 31, 2021 and 2020, respectively.

(h) Disclose whether the registrants audit committee of the board of trustees has considered whether the provision of non-audit services that were rendered to the registrants investment adviser (not including any subadviser whose role is primarily portfolio management and is subcontracted with or overseen by another investment adviser), and any entity controlling, controlled by, or under common control with the investment adviser that provides ongoing services to the registrant that were not pre-approved pursuant to paragraph (c)(7)(ii) of Rule 2-01 of Regulation S-X is compatible with maintaining the principal accountant’s independence.

The Fund’s audit committee of the Board of Trustees has considered whether the provision of non-audit services that were rendered to the Affiliates (as defined) that were not pre- approved pursuant to paragraph (c)(7)(ii) of Rule 2-01 of Regulation S-X is compatible with maintaining the principal accountant’s independence.

ITEM 5. AUDIT COMMITTEE OF LISTED REGISTRANTS

(a) If the registrant is a listed issuer as defined in Rule 10A-3 under the Exchange Act (17 CFR 240.10A-3), state whether or not the registrant has a separately-designated standing audit committee established in accordance with Section 3(a)(58)(A) of the Exchange Act (15 U.S.C. 78c(a)(58)(A)). If the registrant has such a committee, however designated, identify each committee member. If the entire board of directors is acting as the registrant’s audit committee as specified in Section 3(a)(58)(B) of the Exchange Act (15 U.S.C. 78c(a)(58)(B)), so state.

N/A

(b) If applicable, provide the disclosure required by Rule 10A-3(d) under the Exchange Act (17 CFR 240.10A-3(d)) regarding an exemption from the listing standards for audit committees.

N/A

ITEM 6. SCHEDULE OF INVESTMENTS.

File Schedule of Investments in securities of unaffiliated issuers as of the close of the reporting period as set forth in 210.1212 of Regulation S-X [17 CFR 210.12-12], unless the schedule is included as part of the report to shareholders filed under Item 1 of this Form.

Included in Item 1

ITEM 7. DISCLOSURE OF PROXY VOTING POLICIES AND PROCEDURES FOR CLOSED-END MANAGEMENT INVESTMENT COMPANIES.

A closed-end management investment company that is filing an annual report on this Form N-CSR must, unless it invests exclusively in non-voting securities, describe the policies and procedures that it uses to determine how to vote proxies relating to portfolio securities, including the procedures that the company uses when a vote presents a conflict between the interests of its shareholders, on the one hand, and those of the company’s investment adviser; principal underwriter; or any affiliated person (as defined in Section 2(a)(3) of the Investment Company Act of 1940 (15 U.S.C. 80a-2(a)(3)) and the rules thereunder) of the company, its investment adviser, or its principal underwriter, on the other. Include any policies and procedures of the company’s investment adviser, or any other third party, that the company uses, or that are used on the company’s behalf, to determine how to vote proxies relating to portfolio securities.

Not applicable to open-end management investment companies.

ITEM 8. PORTFOLIO MANAGERS OF CLOSED-END MANAGEMENT INVESTMENT COMPANIES.

(a) If the registrant is a closed-end management investment company that is filing an annual report on this Form N-CSR, provide the following information:

(1) State the name, title, and length of service of the person or persons employed by or associated with the registrant or an investment adviser of the registrant who are primarily responsible for the day-to-day management of the registrant’s portfolio (“Portfolio Manager”). Also state each Portfolio Manager’s business experience during the past 5 years.

Not applicable to open-end management investment companies.

ITEM 9. PURCHASES OF EQUITY SECURITIES BY CLOSED-END MANAGEMENT INVESTMENT COMPANY AND AFFILIATED PURCHASERS.

(a) If the registrant is a closed-end management investment company, in the following tabular format, provide the information specified in paragraph (b) of this Item with respect to any purchase made by or on behalf of the registrant or any affiliated purchaser, as defined in Rule 10b-18(a)(3) under the Exchange Act (17 CFR 240.10b-18(a)(3)), of shares or other units of any class of the registrant’s equity securities that is registered by the registrant pursuant to Section 12 of the Exchange Act (15 U.S.C. 781).

Not applicable to open-end management investment companies.

ITEM 10. SUBMISSION OF MATTERS TO A VOTE OF SECURITY HOLDERS.

Describe any material changes to the procedures by which shareholders may recommend nominees to the registrant’s board of directors, where those changes were implemented after the registrant last provided disclosure in response to the requirements of Item 407(c)(2)(iv) of Regulation S-R(17 CFR 229.407)(as required by Item 22(b)(15)) of Schedule 14A (17 CFR 240.14a-101), or this Item.

There have been no material changes to the procedures by which the shareholders may recommend nominees to the registrant’s board of directors since the registrant last provided disclosure in response to the requirements of Item 407(c)(2)(iv) of Regulation S-R of Schedule 14(A) in its definitive proxy statement, or this item.

ITEM 11. CONTROLS AND PROCEDURES.

(a) Disclose the conclusions of the registrant’s principal executive and principal financials officers, or persons performing similar functions, regarding the effectiveness of the registrant’s disclosure controls and procedures (as defined in Rule 30a-3(c) under the Act (17 CFR 270.30a-3(c))) as of a date within 90 days of the filing date of the report that includes the disclosure required by this paragraph, based on the evaluation of these controls and procedures required by Rule 30a-3(b) under the Act (17 CFR 270.30(a)-3(b) and Rules 13a-15(b) or 15d-15(b) under the Exchange Act (17 CFR 240.13a-15(b) or 240.15d-15(b)).

The registrant’s principal executive officer and principal financial officer have concluded that the registrant’s disclosure controls and procedures are effective based on the evaluation of these controls and procedures as of a date within 90 days of the filing date of this report.

(b) Disclose any change in the registrant’s internal control over financial reporting (as defined in Rule 30a-3(d) under the Act (17CFR 270.30a-3(d)) that occured during the second fiscal quarter of the period covered by this report that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting.

There were no significant changes in the registrant’s internal control over financial reporting that occurred during the second fiscal quarter of the period covered by this report that have materially affected, or are reasonably likely to materially affect, the registrant’s internal control over financial reporting.

Item 12. Disclosure of Securities Lending Activities for Closed-End Management Investment Companies.

(a) If the registrant is a closed-end management investment company, provide the following dollar amounts of income and compensation related to the securities lending activities of the registrant during its most recent fiscal year:

N/A

(1) Gross income from securities lending activities;

N/A

(2) All fees and/or compensation for each of the following securities lending activities and related services: any share of revenue generated by the securities lending program paid to the securities lending agent(s) (revenue split); fees paid for cash collateral management services (including fees deducted from a pooled cash collateral reinvestment vehicle) that are not included in the revenue split; administrative fees that are not included in the revenue split; fees for indemnification that are not included in the revenue split; rebates paid to borrowers; and any other fees relating to the securities lending program that are not included in the revenue split, including a description of those other fees;

N/A

(3) The aggregate fees/compensation disclosed pursuant to paragraph (2); and

N/A

(4) Net income from securities lending activities (i.e., the dollar amount in paragraph (1) minus the dollar amount in paragraph (3)).

If a fee for a service is included in the revenue split, state that the fee is included in the revenue split.

N/A

(b) If the registrant is a closed-end management investment company, describe the services provided to the registrant by the securities lending agent in the registrants most recent fiscal year.

N/A

ITEM 13. EXHIBITS.

(a) File the exhibits listed below as part of this Form. Letter or number the exhibits in the sequence indicated.

(1) Any code of ethics, or amendment thereto, that is the subject of the disclosure required by Item 2, to the extent that the registrant intends to satisfy the Item 2 requirements through filing of an exhibit.

(2) A separate certification for each principal executive officer and principal financial officer of the registrant as required by Rule 30a-2(a) under the Act (17 CFR 270.30a-2(a)) , exactly as set forth below:

Filed herewith.

SIGNATURES

[See General Instruction F]

Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

(Registrant) Pioneer Mid Cap Value Fund

By (Signature and Title)* /s/ Lisa M. Jones

Lisa M. Jones, President and Chief Executive Officer

Date January 3, 2022

Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, this report has been signed below by the following persons on behalf of the registrant and in the capacities and on the dates indicated.

By (Signature and Title)* /s/ Lisa M. Jones

Lisa M. Jones, President and Chief Executive Officer

Date January 3, 2022

By (Signature and Title)* /s/ Anthony J. Koenig, Jr.

Anthony J. Koenig, Jr., Managing Director, Chief Operations Officer & Fund Treasurer

Date January 3, 2022

* Print the name and title of each signing officer under his or her signature.

Pioneer Mid Cap Value Fund N-CSRCertified annual shareholder report (management investment company)