BlackRock Duration Income Trust : CEF Quarterly Market Update

Closed-end fund

Market Commentary

Second Quarter 2023

Closed-end fund market overview

Equities moved higher in the second quarter amid moderating inflation, stronger then expected corporate earnings and the Federal Reserve ("Fed") pausing its interest rate hikes for the first time in 15 months. The S&P 500 finished the quarter up 8.7%1. Fixed income markets were down slightly for the quarter as longer-date yields moved higher over the 3-month period. The 10-year US treasury started the quarter at 3.48% and ended at 3.81%. The Bloomberg US Aggregate Bond Index, finished the quarter down -0.8%1. High yield bonds were positive for the quarter given increased investor appetite for risk assets in June.

Closed-end funds ("CEFs*") were up across almost all major categories in the second quarter, with the median CEF up 1.7% on net asset value ("NAV") and up 1.1% on market price2. Equity CEFs (option strategies) were the best performing category for the quarter, up 5.4% on NAV and up 3.6% on market price2.

Second Quarter CEF total returns % (NAV and market price)

Closed-end funds are represented by the following categories: municipal CEFs represented by the General & Insured Muni Debt Funds (Leveraged) Lipper category. High Yield is represented by the High Yield Funds (Leveraged) Lipper category, Investment Grade is represented by the Corporate BBB-Rated Debt Funds (Leveraged) Lipper category. Sector Equity is represented by the Sector Equity CEF Lipper Category, Equity (Options Strategies) is represented by the Options Arbitrage/Option Strategies Lipper Category, General Bond is represented by the General Bond Lipper category and Bank Loans is represented by the Loan Participation Funds Lipper category. "All CEFs" is the median of all the CEF categories.

Source: Lipper as of 6/30/2023. Returns are shown net of advisory fees paid by the fund and net of the fund's operating fees and expenses. Investors who purchase shares of the fund through an investment adviser or other financial professional may separately pay a fee to that service provider. Past performance is not indicative of future results.

CEF discounts widened during the second quarter by 50 basis points. The median CEF industry discount is now -10.7%, wider than the 5-year median industry discount of -7.4%2. Sector equity CEFs currently trade at the widest discounts in the space, at a median of -14.0%2. We believe this has been generally driven by investor aversion to owning growth sectors in a high inflation and rising rate environment. Muni CEFs also trade at wide discounts, currently at -13.0%, likely due to the pressure rising short-term interest rates has had on leverage costs and distribution stability in the space2.

1 Source: Morningstar as of 6/30/2023

2 Source: Lipper as of 6/30/2023 *CEFs refers to the median of the universe.

blackrock.com

Second Quarter 2023 | Closed-end fund market review

USWAH0823U/S-3029778-1/4

5-Year Industry CEF Premium/Discounts

0.0

-2.0

-4.0

-6.0

-8.0

-10.0

-12.0

-14.0

Source: Lipper as of 6/30/2023. Includes entire CEF universe and uses the median premium/discount.

*Bonds are represented by the Bloomberg US Aggregate Bond Index. 3Source: Lipper as of 6/30/2023

4Source: SIFMA as of 6/28/23. The SIFMA Municipal Swap Index is a 7-dayhigh-grade market index comprised of tax-exempt Variable Rate Demand Obligations (VRDOs) with certain characteristics. The Index is calculated and published by Bloomberg. The Index is overseen by SIFMA's Municipal Swap Index Committee.

Second Quarter 2023 | Closed-end fund market review

USWAH0823U/S-3029778-2/4

Equity3

Stocks had a strong second quarter as risk assets rallied in June thanks to a Fed pause in their rate hike cycle, abating inflation, and stronger than expected economic data. Technology and consumer discretionary were the best performing sectors while energy and utilities were down the most in the second quarter. Equity CEFs finished the quarter up a median of 3.2% on NAV and up 2.0% on market price.

Equity (option strategies) discounts widened in the second quarter by 40 bps to finish at a median of -3.7%. Sector equity CEF discounts widened 260 basis points over the quarter, finishing at a median of -14.0%. The widening was magnified in financial CEFs given the negative market sentiment surrounding regional banks.

Current Premium/Discount versus 5-Year Median as of June 30, 2023

Source: Lipper as of 6/30/2023. Distribution rate is calculated by annualizing the fund's latest declared regular distributio n and dividing that number by the funds market price as of the stated date. Distributions are sourced from net investment income, unless noted otherwise. Tax -Equivalent Distribution Rate calculated using a 40.8% effective tax rate.

3 Data sourced from Lipper as of 6/30/2023.

Second Quarter 2023 | Closed-end fund market review

USWAH0823U/S-3029778-3/4

Past performance is not indicativeof future results. You cannot invest directly in an unmanaged index.

Investment return, price, yields and NAV will fluctuate with changes in market conditions. At the time of sale, your shares may have a market price that is above or below net asset value, and may be worth more or less than your original investment. There is no assurance that a fund will meet its investment objective. Closed-end fund shares are not deposits or obligations of, or guaranteed by, any bank and are not insured by the FDIC or any other agency. Investing involves risk, including possible loss of principal amount invested. This is not a prospectus intended for use in the purchase or sale of any fund's shares. Investors should review a fund's prospectus and other publicly available information, including shareholder reports, carefully before investing. Shares may only be purchased or sold through registered broker/dealers. For more information regarding any of BlackRock's closed-end funds, please call BlackRock at 800-882- 0052. No assurance can be given that a fund will achieve its investment objective.

Some BlackRock CEFs may utilize leverage to seek to enhance the yield and net asset value of their common stock, through bank borrowings, issuance of short-term debt securities or shares of preferred stock, or a combination thereof. However, these objectives cannot be achieved in all interest rate environments. While leverage may result in a higher yield for the fund, the use of leverage involves risk, including the potential for higher volatility of the NAV, fluctuations of dividends and other distributions paid by the fund and the market price of the fund's common stock, among others. Certain funds may invest assets in securities of issuers domiciled outside the United States, including issuers from emerging markets. Foreign investing involves special risks, including foreigncurrency risk and the possibility of substantial volatility due to adverse political, economic or other developments.

Some BlackRock CEFs make distributions of ordinary income and capital gains at calendar year end. Those distributions temporarily cause extraordinarily high yields. There is no assurance that a fund will repeat that yield in the future. Subsequent monthly distributions that do not include ordinary income or capital gains in the form of dividends will likely be lower. Fund details, holdings and characteristicsare as of the date noted and subject to change.

The opinions expressed are those of BlackRock as June, 2023, and are subject to change at any time due to changes in market or economic conditions. BlackRock makes no undertaking to change this documentin response to such changes. These comments should not be construed as a recommendation of any individual holdings or market sectors.

General market and credit risks: Debt instruments are subject to credit and interest rate risks. Credit risk refers to the likelihood that an obligor will default in the payment of principal or interest on an instrument. Financial strength and solvency of an obligor are the primary factors influencing credit risk. In addition, lack or inadequacy of collateral or credit enhancement for a debt instrument may affect its credit risk. Credit risk may change over the life of an instrument and debt instrument that are rated by rating agencies are often reviewed and may be subject to downgrade. Interest rate risk refers to the risks associated with market changes in interest rates. Interest rate changes may affect the value of a debt instrument indirectly (especially in the case of fixed rate obligations or directly (especially in the case of instrument whose rates are adjustable). In general, rising interest rates will negatively impact the process of a fixed rate debt instrument and falling interest rates will have a positive effect on price. Adjustable rate instruments also react to interest rate changes in a similar manner although generally to a lesser degree (depending, however, on the characteristics of the reset terms, including the index chosen, frequencyof resetand reset caps or floors, among other factors).

Municipal market risks: There may be less information available on the financial condition of issuers of municipal securities than for public corporations. The market for municipal bonds may be less liquid than taxable bonds. A portion of the income may be taxable. Some investors may be subject to Alternative Minimum Tax (AMT). Capital gain distributions, if any, are taxable. The Fund may utilize leveraging to seek to enhance the yield and net asset value of its common stock, as described in the Fund's prospectus. These objectives will not necessarily be achieved in all interest rate environments. The use of leverage involves risk, including the potential for higher volatility and greater declines of the Fund's net asset value, fluctuations of dividends and other distributions paid by the Fund and the market price of the Fund's common stock, among others.

Equity market risks: The price of equities may rise or fall because of changes in the broad market or changes in a company's financial condition-sometimes rapidly or unpredictable. These price movements may result from factors affecting individual companies, sectors or industries, such as changes in economic or political conditions. Equity securities are subject to "stock market risk" meaning that stock prices may decline over short or extended periods of time.

Index description:

SIFMA Municipal Swap Index: 7-dayhigh-grade market index comprised of tax-exempt Variable Rate Demand Obligations (VRDOs) with certain characteristics. The Index is calculated and published by Bloomberg. The Index is overseen by SIFMA's Municipal Swap Index Committee.

© 2023 BlackRock, Inc. or its affiliates. All Rights Reserved. BLACKROCK is a trademark of BlackRock, Inc. or its affiliates. All other trademarks are those of their respective owners.

Prepared by BlackRock Investments, LLC, member FINRA.

Not FDIC Insured • May Lose Value • No Bank Guarantee

Second Quarter 2023 | Closed-end fund market review

USWAH0823U/S-3029778-4/4