MHI Pioneer Municipal High Income Fund Inc

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ITEM 1. REPORT TO STOCKHOLDERS.

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Pioneer Municipal High Income Fund, Inc.

Semiannual Report  |  October 31, 2023

Ticker Symbol: MHI

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visit us: www.amundi.com/us

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Table of Contents

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President’s Letter	2
Portfolio Management Discussion	4
Portfolio Summary	12
Prices and Distributions	15
Performance Update	16
Schedule of Investments	18
Financial Statements	28
Notes to Financial Statements	34
Additional Information	46
Approval of Renewal of Investment Management Agreement	49
Directors, Officers and Service Providers	54

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President’s Letter

Dear Stockholders,

On February 13, 2023, Amundi US celebrated the 95

th

anniversary of Pioneer Fund, the second-oldest mutual fund in the United States. We recognized the anniversary with ringing of the closing bell at the New York Stock Exchange, which seemed fitting for this special milestone.

Pioneer Fund was launched on February 13, 1928 by Phil Carret, one of the earliest proponents of value investing and a leading innovator in the asset management industry. Mr. Carret began investing in the 1920s and founded Pioneer Investments (now Amundi US) in 1928, and was one of the first investors to realize he could uncover value through rigorous, innovative, fundamental research techniques.

Consistent with Mr. Carret’s investment approach and employing many of the same techniques utilized in the 1920s, Amundi US's portfolio managers have adapted Mr. Carret’s philosophy to a new age of “active” investing.

The last few years have seen investors face some unprecedented challenges, from a global pandemic that shuttered much of the world’s economy for months, to geopolitical strife, to rising inflation that has reached levels not seen in decades. Now, more than ever, Amundi US believes active management – that is, making active investment decisions across all of our portfolios – can help mitigate risk 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 frequently with the management teams of the companies and other entities issuing the securities, and working together to identify those securities that we believe best meet our investment criteria for our family of funds. Our risk management approach begins with each security under consideration, as we strive to develop a deep understanding of the potential opportunity, while considering any potential risk factors.

Today, as stockholders, we have many options. It is our view that active management can serve stockholders 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.

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

Lisa M. Jones
Head of the Americas, President and CEO of US
Amundi Asset Management US, Inc.
December 2023

Any information in this stockholder 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  |  10/31/23

In the following interview, Jonathan Chirunga and David Eurkus discuss the investment environment in the municipal bond market, and the factors that influenced the performance of Pioneer Municipal High Income Fund, Inc. during the six-month period ended October 31, 2023. Mr. Chirunga, Managing Director, Director of High-Yield Municipals, and a portfolio manager at Amundi Asset Management US, Inc. (Amundi US), and Mr. Eurkus, Managing Director, Director of Municipals, and a portfolio manager at Amundi US, are responsible for the day-to-day management of the Fund.

Q	How did the Fund perform during the six-month period ended October 31, 2023?
A	Pioneer Municipal High Income Fund, Inc. returned -15.63% at net asset value (NAV) and -18.58% at market price during the six-month period ended October 31, 2023. During the same six-month period, the Fund’s benchmarks, the Bloomberg US Municipal High Yield Bond Index and the Bloomberg Municipal Bond Index, returned -4.77% and -4.65% at NAV, respectively. The Bloomberg US Municipal High Yield Bond Index (the high-yield municipal index) is an unmanaged measure of the performance of lower-rated municipal bonds, while the Bloomberg Municipal Bond Index is an unmanaged measure of the performance of investment-grade municipal bonds. Unlike the Fund, the indices do not use leverage. While the use of leverage increases investment opportunity, it also increases investment risk.
	During the same six-month period, the average return at NAV of the 30 closed end funds in Morningstar’s Closed End Municipal National Long Funds category (which may or may not be leveraged) was -10.07%, and the average return at market price of the closed-end funds within the same Morningstar category was -13.97%.
	The shares of the Fund were selling at a 16.7% discount to NAV on October 31, 2023. Comparatively, the shares of the Fund were selling at a 13.7% discount to NAV on April 30, 2023.

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	On October 31, 2023, the standardized 30-day SEC yield of the Fund’s shares was 6.07%*.
Q	How would you describe the investment environment in the high-yield municipal bond market during the six-month period ended October 31, 2023?
A	High-yield municipal bonds generated a negative return during the six-month period, reflecting the market’s shifting expectations for US Federal Reserve System (Fed) monetary policy. In the early part of the calendar year, investors were anticipating that the Fed would soon shift to a neutral policy and possibly even begin to cut interest rates at some point in 2023. More recently, however, the combination of persistently high inflation, better-than-expected economic growth, and hawkish comments from Fed officials have caused investors to start factoring in a “higher for longer” approach on interest rates by the US central bank. Expectations for the first Fed interest-rate cut moved further into the future as a result, and, by the end of the period, investors appeared to be anticipating that the Fed would not begin easing monetary policy until late 2024.
	The municipal bond market also experienced difficulties driven by concerns about the need for increased US Treasury issuance to fund the nation’s growing debt, which pushed government bond yields higher and pressured returns across the rest of the fixed-income markets. While high-yield municipal bonds were adversely affected by this trend, they managed to perform mostly in-line with, though slightly behind the performance of investment-grade tax-exempt issues over the six-month period.
Q	What factors affected the Fund’s performance relative to the Bloomberg municipal bond indices during the six-month period ended October 31, 2023?
A	The use of leverage, which tends to augment income but also amplifies the effect of price movements, was a key detractor from the Fund’s benchmark-relative performance over the six-month period, as the high-yield municipal bond market

*	The 30-day SEC yield is a standardized formula that is based on the hypothetical annualized earning power (investment income only) of the Fund’s portfolio securities during the period indicated.

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	experienced a downturn. Unlike the Fund, the two benchmark indices do not use leverage.
	The Fund’s holdings of taxable municipal bonds contributed positively to benchmark-relative performance during the period, as did an underweight to state general obligation debt. On the other hand, allocations to the hospital and transportation sectors detracted from the Fund’s benchmark-relative returns.
	At the individual security level, exposures to District of Columbia Tobacco Settlement Financing Corporation revenue bonds and Maricopa County (Arizona) Industrial Development Authority revenue bonds were the leading positive contributors to the Fund’s benchmark-relative performance. On the other hand Buckeye (Ohio) Tobacco Settlement Financing Authority revenue bonds and Oroville (California) revenue bonds were the largest detractors from the Fund’s relative returns for the six-month period.
	With regard to the Fund’s exposure to tobacco Master Settlement Agreement (MSA) bonds, we have found the bonds to be attractive investments, not only for their potential to enhance performance, but also for the benefits received by the settling states that have issued tobacco bonds since the establishment of the MSA between the settling states and the tobacco-related companies several years ago. Those benefits have included: substantial funding for the advancement of public health; the implementation of important tobacco-related public health measures; and funding towards establishment of a national foundation dedicated to significantly reducing the use of tobacco products among youths.
Q	Did the Fund’s distributions ** to stockholders change during the six-month period ended October 31, 2023?
A	The Fund’s monthly distribution rate decreased from $0.0375 to $0.0325 per share in May 2023, then declined again to $0.0275 in August, and remained at $0.0275 through the end of the period. The decrease in the Fund’s monthly distribution rate over the period was due to an increase in the cost of the leverage incurred by the Fund, which reduced the amount of funds available for

**	Distributions are not guaranteed

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	distribution. The Fund has accumulated undistributed net investment income which is part of the Fund's NAV. A portion of this accumulated net investment income was distributed to stockholders during the period, and these reserves may be depleted over time. A decrease in distributions may have a negative effect on the market value of the Fund's shares.
Q	Did the level of leverage in the Fund change during the six-month period ended October 31, 2023?
A	On October 31, 2023, 37.3% of the Fund’s total managed assets were financed by leverage obtained through the issuance of Variable Rate MuniFund Term Preferred Shares, compared with 35.8% of the Fund’s total managed assets financed by leverage at the start of the period on May 1, 2023. During the six-month period, the Fund decreased the absolute amount of leverage by a total of $16 million, to $113.5 million as of October 31, 2023. Nevertheless, the percentage of the Fund’s managed assets financed by leverage increased during the six-month period due to a decrease in the total net assets of the Fund. The interest rate on the Fund's leverage increased by 106 basis points from May 1, 2023 to October 31, 2023.
Q	Did the Fund have any exposure to derivative securities during the six-month period ended October 31, 2023?
A	No, the Fund’s portfolio had no exposure to derivative securities during the period.
Q	What were some notable aspects of the Fund’s positioning as of October 31, 2023?
A	We have continued to prefer investments in hospital-related issues, since the sector has historically had very low default rates. The revenue received by hospitals has remained diverse, coming from a combination of Medicare, Medicaid, private insurers, and self-payors. The Fund is also overweight to tobacco MSA bonds, due in part to the fact that the sector has never experienced a default. As mentioned previously, tobacco bond revenues have provided substantial funding for the advancement of public health and other similar programs to state and local governments that signed the tobacco MSA.

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	In addition, the Fund is underweight to bonds issued by the Commonwealth of Puerto Rico. The territory’s geographic position makes it vulnerable to hurricane risks, and the local economy’s dependence on tourism means Puerto Rico bonds are potentially more susceptible to a global economic slowdown than bonds of other issuers.  As noted earlier, the Fund is also underweight to state general obligation issues, which have tended to be sensitive to political considerations, as certain state governments may have lower flexibility to raise taxes due to constituents’ preferences, thus limiting their ability to increase revenues. Likewise, governing bodies may be less likely to make the necessary cuts to popular programs.
	As investment-grade municipal bond prices decreased throughout the six-month period, we increased the Fund’s exposure to that area of the market in an effort to capture what we saw as very attractive valuations. We funded the move by reducing the portfolio’s allocation to high-yield municipal bonds.
Q	What is your investment outlook?
A	We anticipate that the shifting interest-rate outlook will continue to impact near-term market performance, given the data-dependent nature of Fed policy. However, slowing consumer spending and decelerating activity in the housing market may indicate that the Fed is moving closer to the point at which it can conclude its monetary tightening cycle. If this turns out to be the case, we believe investors may turn their attention to the positive fundamental traits of the high-yield municipal market, including its low default rate and the continued decline in new-issue supply. We are also encouraged by the opportunities afforded by the compelling yields in the investment-grade municipal bond space.
	As is always the case, headline news events have had a minimal effect on our day-to-day approach to managing the portfolio. Our goal is to invest the Fund in what we believe are fundamentally sound credits with attractive yields, while maintaining an appropriate level of portfolio diversification***. We also seek to avoid experiencing defaults in the portfolio through our emphasis on fundamental research. We believe this steady, long-term

***	Diversification does not assure a profit nor protect against loss.

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approach remains the most effective way to identify opportunities and to help minimize the risk associated with investing in the high-yield municipal market.

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Please refer to the Schedule of Investments on pages 18  - 27  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 high-yield or lower-rated securities are subject to greater-than-average risk.

The Fund may invest in securities of issuers that are in default or that are in bankruptcy.

A portion of income may be subject to state, federal, and/or alternative minimum tax. Capital gains, if any, are subject to a capital gains tax.

When interest rates rise, the prices of debt securities held by the Fund will generally fall. Conversely, when interest rates fall the prices of debt securities held by the Fund generally will rise.

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

The value of municipal securities can be adversely affected by changes in financial condition of municipal issuers, lower revenues, and regulatory and political developments. By concentrating in municipal securities, the Fund is more susceptible to adverse economic, political or regulatory developments than is a portfolio that invests more broadly.

Investments in the Fund are subject to possible loss due to the financial failure of the issuers of the underlying securities and the issuers’ inability to meet their debt obligations.

The Fund may invest up to 20% of its total assets in illiquid securities. Illiquid securities may be difficult to dispose of at a price reflective of their value at the times when the Fund believes it is desirable to do so, and the market price of illiquid securities is generally more volatile than that of more liquid securities. Illiquid securities are also more difficult to value and investment of the Fund’s assets in illiquid securities may restrict the Fund’s ability to take advantage of market opportunities.

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The Fund currently uses leverage through the issuance of preferred shares. Leverage creates significant risks, including the risk that the Fund’s incremental income or capital appreciation for investments purchased with the proceeds of leverage will not be sufficient to cover the cost of the leverage, which may adversely affect the return for the holders of common shares.

The Fund is required to maintain certain regulatory, rating agency and other asset coverage requirements in connection with its outstanding preferred shares. In order to maintain required asset coverage levels, the Fund may be required to alter the composition of its investment portfolio or take other actions, such as redeeming preferred shares with the proceeds from portfolio transactions, at what might be inopportune times in the market. Such actions could reduce the net earnings or returns to holders of the Fund’s common shares over time, which is likely to result in a decrease in the market value of the Fund’s shares.

These risks may increase share price volatility.

Any information in this stockholder 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  |  10/31/23 

Portfolio Diversification

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(As a percentage of total investments)*

Portfolio Maturity

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(As a percentage of total investments)*

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State Diversification

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(As a percentage of total investments)*

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Portfolio Summary  |  10/31/23 

(continued)

10 Largest Holdings

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(As a percentage of total investments)*
1.	Buckeye Tobacco Settlement Financing Authority, Senior Class 2, Series B2, 5.00%, 6/1/55	4.72%
2.	Arkansas Development Finance Authority, Green Bond, 5.45%, 9/1/52	4.04
3.	California Statewide Communities Development Authority, Loma Linda University Medical Center, Series A, 5.00%, 12/1/46 (144A)	3.46
4.	New York Transportation Development Corp., Delta Airlines Inc-LaGuardia, 5.00%, 10/1/40	3.43
5.	Puerto Rico Commonwealth Aqueduct & Sewer Authority, Series A, 5.00%, 7/1/47 (144A)	3.40
6.	Brookhaven Development Authority, Children's Healthcare Of Atlanta, Inc., Series A, 4.00%, 7/1/44	2.94
7.	Iowa Finance Authority, Alcoa Inc. Projects, 4.75%, 8/1/42	2.83
8.	Massachusetts Development Finance Agency, WGBH Educational Foundation, Series A, 5.75%, 1/1/42 (AMBAC Insured)	2.72
9.	Texas Private Activity Bond Surface Transportation Corp., Segment 3C Project, 5.00%, 6/30/58	2.59
10.	City of Houston Airport System Revenue, 4.00%, 7/15/41	2.16

*  Excludes short-term 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.

†

  Amount rounds to less than 0.1%.

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Prices and Distributions  |  10/31/23

Market Value per Common Share

^

	10/31/23	4/30/23
Market Value	$ 6.99	$ 8.78
Discount	(16.69)%	(13.67)%

Net Asset Value per Common Share

^

	10/31/23	4/30/23
Net Asset Value	$8.39	$10.17

Distributions per Common Share*

	Net Investment Income	Short-Term Capital Gains	Long-Term Capital Gains
5/1/23 – 10/31/23	$0.1800	$—	$—

Yields

	10/31/23	4/30/23
30-Day SEC Yield	6.07%	4.50%

The data shown above represents past performance, which is no guarantee of future results.

^  Net asset value and market value are published in 

Barron’s

on Saturday, The 

Wall Street Journal

 on Monday and 

The New York Times

 on Monday and Saturday. Net asset value and market value are published daily on the Fund’s website at 

www.amundi.com/us.

*  The amount of distributions made to stockholders during the period was in excess of the net investment income earned by the Fund during the period. The Fund has accumulated undistributed net investment income which is part of the Fund's net asset value ("NAV"). A portion of this accumulated net investment income was distributed to stockholders during the period, and may be depleted over time. A decrease in distributions may have a negative effect on the market value of the Fund’s shares.

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Performance Update  |  10/31/23

Investment Returns

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The mountain chart on the right shows the change in market value, including reinvestment of dividends and distributions, of a $10,000 investment made in common shares of Pioneer Municipal High Income Fund, Inc. during the periods shown, compared to that of the Bloomberg Municipal Bond Index and Bloomberg U.S. Municipal High Yield Bond Index.

Average Annual Total Return (As of October 31, 2023)
Period	Net Asset Value (NAV)	Market Price	Bloom- berg Municipal Bond Index	Bloom- berg U.S. Municipal High Yield Bond Index
10 Years	1.10%	-1.56%	2.12%	3.79%
5 Years	-2.54	-3.73	1.00	1.67
1 Year	0.45	-7.82	2.64	3.96

Value of $10,000 Investment

Call 1-800-710-0935 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.

Performance data shown represents past performance. Past performance is no guarantee of future results. Investment return and market price will fluctuate, and your shares may trade below NAV due to such factors as interest rate changes and the perceived credit quality of borrowers.

Total investment return does not reflect broker sales charges or commissions. All performance is for common shares of the Fund.

Shares of closed-end funds, unlike open-end funds, are not continuously offered. There is a one-time public offering and, once issued, shares of closed-end funds are bought and sold in the open market through a stock exchange and frequently trade at prices lower than their NAV. NAV per common share is total assets less total liabilities, which include preferred shares or borrowings, as applicable, divided by the number of common shares outstanding.

When NAV is lower than market price, dividends are assumed to be reinvested at the greater of NAV or 95% of the market price. When NAV is higher, dividends are assumed to be reinvested at prices obtained through open-market purchases under the Fund’s dividend reinvestment plan.

The performance table and graph do not reflect the deduction of fees and taxes that a stockholder would pay on Fund distributions or the sale of Fund shares. Had these fees and taxes been reflected, performance would have been lower.

The Bloomberg Municipal Bond Index is an unmanaged, broad measure of the municipal bond market. The Bloomberg U.S. Municipal High Yield Bond Index is unmanaged, totals over $26 billion in market value and maintains over 1,300 securities. Municipal bonds in this index have the following requirements: maturities of one year or greater, sub investment grade (below Baa or non-rated), fixed coupon rate, issued after 12/31/90, deal size over $20 million,

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and the average liquidation value outstanding of VMTP Shares for the Fund during the six months ended October 31, 2023, was $127,315,217.

The Fund did not incur any offering costs as a result of the offerings on February 9, 2018 and February 16, 2021.

Transactions in the Series 2021 VMTP Shares during the Fund’s current and
prior reporting periods were as follows:

	Period Ended 10/31/23		Year Ended 4/30/23
	Shares	Amount	Shares	Amount
VMTP Shares issued	—	$ —	—	$ —
VMTP Shares redeemed	(155)	(15,500,000)	(160)	(16,000,000)
Net decrease	(155)	$(15,500,000)	(160)	$(16,000,000)

7. Subsequent Events

A monthly distribution was declared on November 3, 2023 of $0.0275 per share payable November 30, 2023 to stockholders of record on November 16, 2023.

Subsequent to October 31, 2023, dividends declared and paid on VMTP Shares totaled $538,450 through November 30, 2023. 

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Additional Information

Notice is hereby given in accordance with Section 23(c) of the Investment Company Act of 1940 that the Fund may purchase, from time to time, its shares in the open market.

Results of Annual Meeting of Stockholders

The Annual Meeting of Stockholders of Pioneer Municipal High Income Fund, Inc. was held on September 12, 2023.  Following is a description of the proposal considered at the Meeting and the number of shares of Common Stock and Preferred Stock voted:

Proposal - To elect three Class II Directors of the Fund, each to serve until the third annual meeting following his or her election and until his or her successor is duly elected and qualifies:

Nominee	Votes For	Votes Against	Votes Abstained
Diane Durnin*	17,531,959	1,653,714	176,404
Benjamin M. Friedman*	15,767,900	3,412,768	181,407
Kenneth J. Taubes*	17,711,195	1,446,502	204.382
* Elected by holders of shares of Common Stock and Preferred Stock voting together as a single class.

Each of Ms. Durnin, Dr. Friedman and Mr. Taubes received a majority of all of the votes entitled to be cast with respect to his or her election by the stockholders of the Fund, and was elected as a Director of the Fund. 

In addition to Ms. Durnin, Dr. Friedman and Mr. Taubes, the other Directors of the Fund at the time of the Annual Meeting, John E. Baumgardner, Jr., Lisa M. Jones, Craig C. MacKay, Lorraine H. Monchak, Thomas J. Perna, Marguerite A. Piret and Fred J. Ricciardi, continue to serve as Directors of the Fund.

Anti-takeover provisions.

The Fund's Charter and Bylaws include provisions that are designed to limit the ability of other entities or persons to acquire control of the Fund for short-term objectives, including by converting the Fund to open-end status or changing the composition of the Board, that may be detrimental to the Fund's ability to achieve its primary investment objective of seeking to provide its common stockholders with a high level of current income. These provisions include staggered terms of service for the Directors, advance notice requirements for stockholder proposals, and super-majority voting requirements for certain transactions with affiliates, open-ending the Fund or a merger, liquidation, asset sale or similar transaction. The Fund's Bylaws also contain a provision providing that the Board of Directors has adopted a resolution to opt in the Fund to the provisions of the Maryland Control Share Acquisition Act ("MCSAA"). Such provisions may limit the ability of stockholders to sell their shares at a

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premium over prevailing market prices by discouraging a third party from seeking to obtain control of the Fund. There can be no assurance, however, that such provisions will be sufficient to deter activist investors that seek to cause the Fund to take actions that may not be aligned with the interests of long-term stockholders. Furthermore, the law is uncertain on the use of control share provisions. Certain courts have found that control share provisions in the by-laws of closed-end funds are inconsistent with the 1940 Act. It is possible that a court could decide that the Fund's decision to opt in to the MCSAA is inconsistent with the 1940 Act.

Exclusive forum provisions. The Fund's Bylaws designate the Circuit Court for Baltimore City, Maryland as the sole and exclusive forum for certain types of actions and proceedings that may be initiated by the Fund's stockholders and provide that claims relating to causes of action under the United States federal securities laws may only be brought in the United States District Court for the District of Maryland, Northern Division, which could limit stockholders' ability to obtain a favorable judicial forum for disputes with the Fund or its directors, officers or the Fund's agents, if any, and could discourage lawsuits against the Fund and its directors, officers and agents, if any.

The Fund's Bylaws provide that, unless the Fund consents in writing to the selection of an alternative forum, the Circuit Court for Baltimore City, Maryland, or, if that court does not have jurisdiction, the United States District Court for the District of Maryland, Northern Division, will be the sole and exclusive forum for (a) any Internal Corporate Claim, as such term is defined in the MGCL, (b) any derivative action or proceeding brought on the Fund's behalf (other than actions arising under federal securities laws), (c) any action asserting a claim of breach of any duty owed by any of the Fund's directors, officers or other agents to the Fund or to the Fund's stockholders, (d) any action asserting a claim against the Fund or any of the Fund's directors, officers or other agents arising pursuant to any provision of the MGCL or the Fund's Charter or Bylaws or (e) any other action asserting a claim against the Fund or any of the Fund's directors, officers or other agents that is governed by the internal affairs doctrine. Furthermore, the Fund's Bylaws provide that, unless the Fund consents in writing to the selection of an alternative forum, the United States District Court for the District of Maryland, Northern Division shall, to the fullest extent permitted by law, be the sole and exclusive forum for the resolution of any claim arising under the United States federal securities laws.

These exclusive forum provisions may limit the ability of the Fund's stockholders to bring a claim in a judicial forum that such stockholders find favorable for disputes with the Fund or the Fund's directors, officers, or agents, if any, which may discourage such lawsuits against the Fund and

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the Fund's directors, officers, and agents, if any. Alternatively, if a court were to find the choice of forum provisions contained in the Fund's Bylaws to be inapplicable or unenforceable in an action, the Fund may incur additional costs associated with resolving such action in other jurisdictions, which could materially adversely affect the Fund's business, financial condition, and operating results.

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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 Municipal High Income Fund, Inc. (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 Directors of the Fund, including a majority of the Fund’s Independent Directors, must determine annually whether to renew the investment management agreement for the Fund.

The contract review process began in January 2023 as the Directors of the Fund agreed on, among other things, an overall approach and timeline for the process. Contract review materials were provided to the Directors in March 2023, July 2023 and September 2023. In addition, the Directors 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 Directors at regularly scheduled meetings, in connection with the review of the Fund’s investment management agreement.

In March 2023, the Directors, among other things, discussed the memorandum provided by Fund counsel that summarized the legal standards and other considerations that are relevant to the Directors 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 2023, the Directors, 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 Directors 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 Directors further considered contract review materials, including additional materials received in response to the Directors’ request, in September 2023. 

At a meeting held on September 19, 2023, based on their evaluation of the information provided by Amundi US and third parties, the Directors of the Fund, including the Independent Directors voting separately advised by independent counsel, unanimously approved the renewal of the investment

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management agreement for another year. In approving the renewal of the investment management agreement, the Directors considered various factors that they determined were relevant, including the factors described below. The Directors 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 Directors 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 Directors also reviewed Amundi US’s investment approach for the Fund and its research process. The Directors 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 Directors considered the compliance services being provided to the Fund by Amundi US and how Amundi US has addressed any compliance issues during the past year. The Directors noted the substantial attention and high priority given by Amundi US’s senior management to the Pioneer Fund complex, including with respect to the increasing regulation to which the Pioneer Funds are subject. 

The Directors 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 Directors also considered that, as administrator, Amundi US is responsible for the administration of the Fund’s business and other affairs. The Directors 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 Directors 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 Directors 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. The Directors also regularly consider the Fund’s returns at market value relative to its peers, as well as the discount at which the Fund’s shares may trade on the New York Stock Exchange compared to its net asset value per share. They also discuss the Fund’s performance with Amundi US on a regular basis. The Directors’ regular reviews and discussions were factored into the Directors’ deliberations concerning the renewal of the investment management agreement.

Management Fee and Expenses. 

The Directors considered information showing the fees and expenses of the Fund in comparison to the management fees and expense ratios of a peer group of funds selected on the basis of criteria determined by the Independent Directors 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 stockholders.

The Directors considered that the Fund’s management fee (based on managed assets) for the most recent fiscal year was in the second quintile relative to the management fees paid by other funds in its Strategic Insight peer group for the comparable period. The Directors considered that the expense ratio (based on managed assets) of the Fund’s common shares for the most recent fiscal year was in the first  quintile (including investment-related expenses) and in the third quintile (excluding investment-related expenses), in each case relative to its Strategic Insight peer group for the comparable period.   

The Directors 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 Directors 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 Directors took into account the respective demands, resources and complexity associated with the Fund and other client accounts. The Directors 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,

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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 Directors also considered the entrepreneurial risks associated with Amundi US’s management of the Fund.

The Directors 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 Directors 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 Directors 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 Directors 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 Directors concluded that Amundi US’s profitability with respect to the management of the Fund was not unreasonable.

Economies of Scale. 

The Directors considered the extent to which Amundi US may realize economies of scale or other efficiencies in managing and supporting the Fund. Since the Fund is a closed-end fund that has not raised additional capital, the Directors concluded that economies of scale were not a relevant consideration in the renewal of the investment advisory agreement.

Other Benefits. 

The Directors considered the other benefits that Amundi US enjoys from its relationship with the Fund. The Directors 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 Directors further considered the revenues and profitability of Amundi US’s businesses other than the Fund business. To the extent applicable, the Directors 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.

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The Directors 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 $2.1 trillion in assets (including the Pioneer Funds). The Directors 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 Directors 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 Directors 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 Directors 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 Directors, including the Independent Directors, 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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Directors, Officers and Service Providers

 

Directors

Thomas J. Perna, Chairman

John E. Baumgardner, Jr.

Diane Durnin

Benjamin M. Friedman

Lisa M. Jones

Lorraine H. Monchak

Craig C. MacKay

Marguerite A. Piret

Fred J. Ricciardi

Kenneth J. Taubes

Officers

Lisa M. Jones, President and
Chief Executive Officer

Anthony J. Koenig, Jr., Treasurer
and Chief Financial and
Accounting Officer

Christopher J. Kelley, Secretary and
Chief Legal Officer

 

Investment Adviser and Administrator

Amundi Asset Management US, Inc.

Custodian and Sub-Administrator

The Bank of New York Mellon Corporation

Independent Registered Public Accounting Firm

Ernst & Young LLP

Legal Counsel

Morgan, Lewis & Bockius LLP

Transfer Agent

Equiniti Trust Company, LLC

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 stockholders at www.amundi.com/us. This information is also available on the Securities and Exchange Commission’s web site at www.sec.gov.

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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.

You can call Equiniti Trust Company, LLC (EQ) for:

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Account Information

 

1-800-710-0935

Or write to EQ:

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For

Write to

General inquiries, lost dividend checks,

Equiniti Trust
change of address, lost stock certificates,

Company, LLC
stock transfer

Operations Center
6201 15th Ave.

Brooklyn, NY 11219

Dividend reinvestment plan (DRIP)

Equiniti Trust
Company, LLC

Wall Street Station

P.O. Box 922

New York, NY 10269-0560

Website

 https://equiniti.com/us

For additional information, please contact your investment advisor or visit our web site www.amundi.com/us.

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. Stockholders may view the filed Form N-PORT by visiting the Commission’s web site at https://www.sec.gov.

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Amundi Asset Management US, Inc.
60 State Street
Boston, MA 02109

www.amundi.com/us

© 2023 Amundi Asset Management US, Inc. 19442-17-1223

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 Directors 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 Directors 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 Directors, 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 Director, 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.

N/A

(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.

N/A

(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.

N/A

(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.

N/A

(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

SECTION III - POLICY DETAIL, CONTINUED

SECTION III - POLICY DETAIL, CONTINUED

SECTION III - POLICY DETAIL, CONTINUED

GENERAL AUDIT COMMITTEE APPROVAL 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.

N/A

(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.

N/A

(h) Disclose whether the registrants audit committee of the Board of Directors 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 Directors 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.

(i) A registrant identified by the Commission pursuant to Section 104(i)(2)(A) of the Sarbanes-Oxley Act of 2002 (15 U.S.C. 7214(i)(2)(A)), as having retained, for the preparation of the audit report on its financial statements included in the Form NCSR, a registered public accounting firm that has a branch or office that is located in a foreign jurisdiction and that the Public Company Accounting Oversight Board has determined it is unable to inspect or investigate completely because of a position taken by an authority in the foreign jurisdiction must electronically submit to the Commission on a supplemental basis documentation that establishes that the registrant is not owned or controlled by a governmental entity in the foreign jurisdiction. The registrant must submit this documentation on or before the due date for this form. A registrant that is owned or controlled by a foreign governmental entity is not required to submit such documentation.

N/A

(j) A registrant that is a foreign issuer, as defined in 17 CFR 240.3b-4, identified by the Commission pursuant to Section 104(i)(2)(A) of the Sarbanes-Oxley Act of 2002 (15 U.S.C. 7214(i)(2)(A)), as having retained, for the preparation of the audit report on its financial statements included in the Form N-CSR, a registered public accounting firm that has a branch or office that is located in a foreign jurisdiction and that the Public Company Accounting Oversight Board has determined it is unable to inspect or investigate completely because of a position taken by an authority in the foreign jurisdiction, for each year in which the registrant is so identified, must provide the below disclosures. Also, any such identified foreign issuer that uses a variable-interest entity or any similar structure that results in additional foreign entities being consolidated in the financial statements of the registrant is required to provide the below disclosures for itself and its consolidated foreign operating entity or entities. A registrant must disclose:

(1) That, for the immediately preceding annual financial statement period, a registered public accounting firm that the PCAOB was unable to inspect or investigate completely, because of a position taken by an authority in the foreign jurisdiction, issued an audit report for the registrant;

N/A

(2) The percentage of shares of the registrant owned by governmental entities in the foreign jurisdiction in which the registrant is incorporated or otherwise organized;

N/A

(3) Whether governmental entities in the applicable foreign jurisdiction with respect to that registered public accounting firm have a controlling financial interest with respect to the registrant;

N/A

(4) The name of each official of the Chinese Communist Party who is a member of the board of directors of the registrant or the operating entity with respect to the registrant;

N/A

(5) Whether the articles of incorporation of the registrant (or equivalent organizing document) contains any charter of the Chinese Communist Party, including the text of any such charter.

N/A

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.

N/A

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.

N/A

.

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).

N/A

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 occurred during 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 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.

(b) Certifications pursuant to Rule 30a-2(b) under the 1940 Act and Section 906 of the Sarbanes-Oxley Act of 2002 are attached hereto.

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 Municipal High Income Fund, Inc.

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

Lisa M. Jones, President and Chief Executive Officer

Date January 3, 2024

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, 2024

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

Anthony J. Koenig, Jr., Managing Director, Chief Operations Officer & Treasurer of the Funds

Date January 3, 2024

CODE OF ETHICS

FOR

SENIOR OFFICERS

POLICY

This Code of Ethics for Senior Officers (this “Code”) sets forth the policies, practices and values expected to be exhibited by Senior Officers of the Pioneer Funds (collectively, the “Funds” and each, a “Fund”). This Code does not apply generally to officers and employees of service providers to the Funds, including Amundi Asset Management US, Inc., and Amundi Distributor US, Inc. (collectively, “Amundi US”), unless such officers and employees are also Senior Officers.

The term “Senior Officers” shall mean the principal executive officer, principal financial officer, principal accounting officer and controller of the Funds, although one person may occupy more than one such office. Each Senior Officer is identified by title in Exhibit A to this Code.

The Chief Compliance Officer (“CCO”) of the Pioneer Funds is primarily responsible for implementing and monitoring compliance with this Code, subject to the overall supervision of the Board of Directors of the Funds (the “Board”). The CCO has the authority to interpret this Code and its applicability to particular situations. Any questions about this Code should be directed to the CCO or his or her designee.

PURPOSE

The purposes of this Code are to:

Each Senior Officer should adhere to a high standard of business ethics and should be sensitive to situations that may give rise to actual as well as apparent conflicts of interest.

RESPONSIBILITIES OF SENIOR OFFICERS

Conflicts of Interest

A “conflict of interest” occurs when a Senior Officer’s private interests interfere in any way – or even appear to interfere – with the interests of or his/her service to a Fund. A conflict can arise when a Senior Officer takes actions or has interests that may make it difficult to perform his or her Fund work objectively and effectively. Conflicts of interest also arise when a Senior Officer or a member of his/her family receives improper personal benefits as a result of the Senior Officer’s position with the Fund.

Certain conflicts of interest arise out of the relationships between Senior Officers and the Fund and already are subject to conflict of interest provisions in the Investment Company Act of 1940, as amended (the “ICA”), and the Investment Advisers Act of 1940, as amended (the “IAA”). For example, Senior Officers may not individually engage in certain transactions (such as the purchase or sale of securities or other property) with the Funds because of their status as “affiliated persons” of the Funds. The Fund’s and Amundi US’ compliance programs and procedures are designed to prevent, or identify and correct, violations of these provisions. This Code does not, and is not intended to, repeat or replace such policies and procedures, and such conflicts fall outside of the parameters of this Code.

Although typically not presenting an opportunity for improper personal benefit, conflicts arise as a result of the contractual relationship between the Fund and Amundi US because the Senior Officers are officers or employees of both. As a result, this Code recognizes that Senior Officers will, in the normal course of their duties (whether formally for a Fund or for Amundi US, or for both), be involved in establishing policies and implementing decisions that will have different effects on Amundi US and the Fund. The participation of Senior Officers in such activities is inherent in the contractual relationship between a Fund and Amundi US and is consistent with the performance by the Senior Officers of their duties as officers of the Fund and, if addressed in conformity with the provisions of the ICA and the IAA, will be deemed to have been handled ethically. In addition, it is recognized by the Board that Senior Officers may also be officers of investment companies other than the Pioneer Funds.

Other conflicts of interest are covered by this Code, even if such conflicts of interest are not subject to provisions of the ICA or the IAA. In reading the following examples of conflicts of interest under this Code, Senior Officers should keep in mind that such a list cannot ever be exhaustive or cover every possible scenario. It follows that the overarching principle is that the personal interest of a Senior Officer should not be placed improperly before the interest of a Fund.

Each Senior Officer must:

Any material conflict of interest situation should be approved by the CCO, his or her designee or the Board. Examples of these include:

Corporate Opportunities

Senior Officers may not (a) take for themselves personally opportunities that are discovered through the use of a Fund’s property, information or position; (b) use a Fund’s property, information, or position for personal gain; or (c) compete with a Fund. Senior Officers owe a duty to the Funds to advance their legitimate interests when the opportunity to do so arises.

Confidentiality

Senior Officers should maintain the confidentiality of information entrusted to them by the Funds, except when disclosure is authorized or legally mandated. Confidential information includes all non-public information that might be of use to competitors, or harmful to the Funds, if disclosed.

Fair dealing with Fund shareholders, suppliers, and competitors

Senior Officers should endeavor to deal fairly with the Funds’ shareholders, suppliers, and competitors. Senior Officers should not take unfair advantage of anyone through manipulation, concealment, abuse of privileged information, misrepresentation of material facts, or any other unfair-dealing practice. Senior Officers should not knowingly misrepresent or cause others to misrepresent facts about a Fund to others, whether within or outside the Fund, including to the Board, the Funds’ auditors or to governmental regulators and self-regulatory organizations.

Compliance with Law

Each Senior Officer must not knowingly violate any law, rule and regulation applicable to his or her activities as an officer of the Funds. In addition, Senior Officers are responsible for understanding and promoting compliance with the laws, rules and regulations applicable to his or her particular position and by persons under the Senior Officer’s supervision. Senior Officers should endeavor to comply not only with the letter of the law, but also with the spirit of the law.

Disclosure

Each Senior Officer should familiarize himself or herself with the disclosure requirements generally applicable to the Funds. Each Senior Officer should, to the extent appropriate within his or her area of responsibility, consult with other officers of the Funds and Amundi US with the goal of promoting full, fair, accurate, timely and understandable disclosure in the reports and documents a Fund files with, or submits to, the SEC and in other public communications made by the Funds.

INITIAL AND ANNUAL CERTIFICATIONS

Upon becoming a Senior Officer the Senior Officer is required to certify that he or she has received, read, and understands this Code. On an annual basis, each Senior Officer must certify that he or she has complied with all of the applicable requirements of this Code.

ADMINISTRATION AND ENFORCEMENT OF THE CODE

Report of Violations

Amundi US relies on each Senior Officer to report promptly if he or she knows of any conduct by a Senior Officer in violation of this Code. All violations or suspected violations of this Code must be reported to the CCO or a member of Amundi US’ Legal and Compliance Department. Failure to do so is itself a violation of this Code.

Investigation of Violations

Upon notification of a violation or suspected violation, the CCO or other members of Amundi US’ Compliance Department will take all appropriate action to investigate the potential violation reported. If, after such investigation, the CCO believes that no violation has occurred, the CCO and Compliance Department is not required to take no further action. Any matter the CCO believes is a violation will be reported to the Independent Directors. If the Independent Directors concur that a violation has occurred, they will inform and make a recommendation to the full Board. The Board shall be responsible for determining appropriate action. The Funds, their officers and employees, will not retaliate against any Senior Officer for reports of potential violations that are made in good faith and without malicious intent.

The CCO or his or her designee is responsible for applying this Code to specific situations in which questions are presented under it and has the authority to interpret this Code in any particular situation. The CCO or his or her designee shall make inquiries regarding any potential conflict of interest.

Violations and Sanctions

Compliance with this Code is expected and violations of its provisions will be taken seriously and could result in disciplinary action. In response to violations of the Code, the Board may impose such sanctions as it deems appropriate within the scope of its authority over Senior Officers, including termination as an officer of the Funds.

Waivers from the Code

The Independent Directors will consider any approval or waiver sought by any Senior Officer.

The Independent Directors will be responsible for granting waivers, as appropriate. Any change to or waiver of this Code will, to the extent required, be disclosed as provided by SEC rules.

OTHER POLICIES AND PROCEDURES

This Code shall be the sole Code of Ethics adopted by the Funds for purposes of Section 406 of the Sarbanes-Oxley Act and the rules and forms applicable to registered investment companies thereunder. The Funds’ and Amundi US’ Codes of Ethics under Rule 17j-1 under the ICA and Rule 204A-1 of the IAA are separate requirements applying to the Senior Officers and others, and are not a part of this Code. To the extent any other policies and procedures of the Funds or Amundi US overlap or conflict with the provisions of the Code, they are superseded by this Code.

SCOPE OF RESPONSIBILITIES

A Senior Officer’s responsibilities under this Code are limited to Fund matters over which the Senior Officer has direct responsibility or control, matters in which the Senior Officer routinely participates, and matters with which the Senior Officer is otherwise involved. In addition, a Senior Officer is responsible for matters of which the Senior Officer has actual knowledge.

AMENDMENTS

This Code other than Exhibit A may not be amended except in a writing that is specifically approved or ratified by a majority vote of the Board, including a majority of the Independent Directors.

CONFIDENTIALITY

All reports and records prepared or maintained pursuant to this Code will be considered confidential and shall be maintained and protected accordingly. Except as otherwise required by law or this Code, such matters shall not be disclosed to anyone other than the Board and their counsel, or to Amundi US’ Legal and Compliance Department.

INTERNAL USE

This Code is intended solely for the internal use by the Funds and does not constitute an admission, by or on behalf of any Fund, as to any fact, circumstance, or legal conclusion.

EXHIBIT A – SENIOR OFFICERS OF THE PIONEER FUNDS (EFFECTIVE AS OF AUGUST 14, 2008)

President (Principal Executive Officer)

Treasurer (Principal Financial Officer)

CERTIFICATION PURSUANT TO RULE 30a-2(a)

UNDER THE 1940 ACT AND SECTION 302

OF THE SARBANES-OXLEY ACT OF 2002

I, Lisa M. Jones, certify that:

1. I have reviewed this report on Form N-CSR of Pioneer Municipal High Income Fund, Inc.;

2. Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

3. Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations, changes in net assets, and cash flows (if the financial statements are required to include a statement of cash flows) of the registrant as of, and for, the periods presented in this report;

4. The registrant’s other certifying officer and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Rule 30a-3(c) under the Investment Company Act of 1940) and internal control over financial reporting (as defined in Rule 30a-3(d) under the Investment Company Act of 1940) for the registrant and have:

a. Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

b. Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

c. Evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of a date within 90 days prior to the filing date of this report based on such evaluation; and

d. Disclosed in this report any change in the registrants internal control over financial reporting that occurred during the period covered by this report that has materially affected, or is reasonably likely to materially affect, the registrants internal control over financial reporting; and

5. The registrants other certifying officer and I have disclosed to the registrant’s auditors and the audit committee of the registrant’s board of directors (or persons performing the equivalent functions):

a. All significant deficiencies in the design or operation of internal controls over financial reporting which are reasonably likely to adversely affect the registrant’s ability to record, process, summarize, and report financial information; and

b. Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant’s internal control over financial reporting.

Date: January 3, 2024

/s/ Lisa M. Jones

Lisa M. Jones

President and Chief Executive Officer

CERTIFICATION PURSUANT TO RULE 30a-2(a)

UNDER THE 1940 ACT AND SECTION 302

OF THE SARBANES-OXLEY ACT OF 2002

I, Anthony J. Koenig, Jr., certify that:

1. I have reviewed this report on Form N-CSR of Pioneer Municipal High Income Fund, Inc.;

2. Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

3. Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations, changes in net assets, and cash flows (if the financial statements are required to include a statement of cash flows) of the registrant as of, and for, the periods presented in this report;

4. The registrants other certifying officer and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Rule 30a-3(c) under the Investment Company Act of 1940) and internal control over financial reporting (as defined in Rule 30a-3(d) under the Investment Company Act of 1940) for the registrant and have:

a. Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

b. Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

c. Evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of a date within 90 days prior to the filing date of this report based on such evaluation; and

d. Disclosed in this report any change in the registrants internal control over financial reporting that occurred during the period covered by this report that has materially affected, or is reasonably likely to materially affect, the registrants internal control over financial reporting; and

5. The registrants other certifying officer and I have disclosed to the registrant’s auditors and the audit committee of the registrant’s board of directors (or persons performing the equivalent functions):

a. All significant deficiencies in the design or operation of internal controls over financial reporting which are reasonably likely to adversely affect the registrant’s ability to record, process, summarize, and report financial information; and

b. Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant’s internal control over financial reporting.

Date: January 3, 2024

/s/ Anthony J. Koenig, Jr

Anthony J. Koenig, Jr.

Managing Director, Chief Operations Officer & Treasurer of the Funds

CERTIFICATION PURSUANT TO

18 U.S.C. SECTION 1350,

AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY

ACT OF 2002

I, Lisa M. Jones, certify that, to the best of my knowledge:

1. The Form N-CSR (the Report) of Pioneer Municipal High Income Fund, Inc. fully complies for the period covered by the Report with the requirements of Section 13(a) or 15 (d), as applicable, of the Securities Exchange Act of 1934; and

2. The information contained in the Report fairly presents, in all material respects, the financial condition and results of the operations of the Fund.

Date: January 3, 2024

/s/ Lisa M. Jones

Lisa M. Jones

President and Chief Executive Officer

This certification is being furnished pursuant to Rule 30a-2(b) under the Investment Company Act of 1940, as amended, and 18 U.S.C. section 1350 and is not being filed as part of the Report with the Securities and Exchange Commission.

A signed original of this written statement required by section 906 has been provided to the Fund and will be retained by the Fund and furnished to the Securities Exchange Commission or its staff upon request.

CERTIFICATION PURSUANT TO

18 U.S.C. SECTION 1350,

AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY

ACT OF 2002

I, Anthony J. Koenig, Jr., certify that, to the best of my knowledge:

1. The Form N-CSR (the Report) of Pioneer Municipal High Income Fund, Inc. fully complies for the period covered by the Report with the requirements of Section 13(a) or 15 (d), as applicable, of the Securities Exchange Act of 1934; and

2. The information contained in the Report fairly presents, in all material respects, the financial condition and results of the operations of the Fund.

Date: January 3, 2024

/s/ Anthony J. Koenig, Jr.

Anthony J. Koenig, Jr.

Managing Director, Chief Operations Officer & Treasurer of the Funds

This certification is being furnished pursuant to Rule 30a-2(b) under the Investment Company Act of 1940, as amended, and 18 U.S.C. section 1350 and is not being filed as part of the Report with the Securities and Exchange Commission.

A signed original of this written statement required by section 906 has been provided to the Fund and will be retained by the Fund and furnished to the Securities Exchange Commission or its staff upon request.

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