BlackRock Sustainable Total Return Fund

C000230844 Fund Overview

BlackRock Sustainable Total Return Fund is a US mutual fund managed by BlackRock Bond Fund, Inc., categorised as Long Securitized (MBS/ABS/CMBS) Bond. ABC INVEST provides holdings, performance, costs, cashflows, risk data, prospectus documents and SEC filings, sourced from SEC filings.

• Type: US mutual fund
• Manager: BlackRock Bond Fund, Inc.
• Category: Long Securitized (MBS/ABS/CMBS) Bond
• Assets under management: $45.31M
• 1-year return: 5.9%
• SEC CIK: 0000276463
• SEC series ID: S000073727
• Share class ID: C000230844

C000230844 Investment Objective and Strategy

BlackRock Sustainable Total Return Fund describes its objective and strategy as follows, from its latest prospectus filed with the SEC by BlackRock Bond Fund, Inc..

Investment objective

The investment objective of the BlackRock Sustainable Total Return Fund (the Fund) is to realize a total return that exceeds that of the Bloomberg U.S. Aggregate Bond Index (the Benchmark) while seeking to maintain certain environmental, social and governance (ESG) characteristics, climate risk exposure and climate opportunities relative to the Benchmark.

Principal investment strategy

The Fund typically invests more than 90% of its assets in a diversified portfolio of fixed-income securities. The fixed-income securities in which the Fund invests include: ? U.S. Government debt securities ? Corporate debt securities issued by U.S. and foreign companies ? Asset-backed securities ? Mortgage-backed securities ? Preferred securities issued by U.S. and foreign companies ? Corporate debt securities and preferred securities convertible into common stock ? Foreign sovereign debt instruments ? Money market securities Under normal circumstances, the Fund invests at least 80% of its assets in bonds. For the purposes of this strategy, bonds include the following: obligations issued or guaranteed by the U.S. Government or a foreign government or their agencies, instrumentalities or political subdivisions; mortgage-backed securities, including agency mortgage pass-through securities and commercial mortgage-backed securities; mortgage to-be-announced (TBA) securities; debt obligations of U.S.

or foreign issuers; municipal securities; and asset-backed securities. The Fund invests primarily in fixed-income securities that are rated in the four highest rating categories by at least one of the recognized rating agencies (including Baa or better by Moodys Investor Service, Inc. (Moodys) or BBB or better by S&P Global Ratings (S&P) or Fitch Ratings (Fitch)) or determined by the Funds management team to be of similar quality. Securities rated in any of the four highest rating categories are known as investment grade securities. The Fund will allocate at least 10% of its assets in aggregate to Green, Social and Sustainability (GSS) bonds and impact mortgages. GSS bonds are bonds with proceeds that are tied to green and socially responsible projects, as determined by Fund management.

Impact mortgages are securities issued or guaranteed by the U.S. government, its agencies or instrumentalities, which have characteristics that Fund management has deemed to have a positive social impact. Impact mortgages may include, but are not limited to, rural housing, manufactured housing, housing pools issued by State Housing Finance Authorities and bespoke impact mortgage-backed security pools. To determine the Funds investable universe, Fund management will first seek to screen out certain issuers based on ESG criteria determined by BlackRock, subject to the considerations noted below. Such screening criteria principally includes: (i) issuers that derive more than zero percent of revenue from the production of controversial weapons; (ii) issuers that derive more than zero percent of revenue from the production of civilian firearms; (iii) issuers that derive more than zero percent of revenue from the production of tobacco-related products; (iv) issuers that derive more than five percent of revenue from thermal coal generation, unless such issuers either (a) have made certain commitments to reduce climate impact or (b) derive at least fifty percent of revenue from alternative energy sources; (v) issuers that derive more than five percent of revenue from thermal coal mining; (vi) issuers that derive more than five percent of revenue from oil sands extraction; (vii) issuers ranked in the bottom half of the applicable fossil issuers peer group by recognized third-party rating agencies; (viii) issuers with evidence of fossil fuel reserves associated with energy applications; (ix) issuers identified as violators of the United Nations Global Compact, which are globally accepted principles covering corporate behavior in the areas of human rights, labor, environment, and anti-corruption; and (x) issuers receiving an ESG rating of CCC (or equivalent) by recognized third-party rating agencies.

Notwithstanding the foregoing, the Fund may invest in green bonds of issuers that exceed the thresholds stated in (iv), (v), (vi), (vii) and (viii) above. The Fund relies on one or more third-party ratings agencies to identify issuers for purposes of the above screening criteria. Third-party rating agencies may base the above screening criteria on an estimate when revenue for a covered business activity is not disclosed by the issuer or publicly available. The Funds screening criteria is measured at the time of investment and is dependent upon information and data that may be incomplete, inaccurate, unavailable or estimated. Where the Funds screening criteria looks solely to third-party ratings or data, issuers are only screened to the extent such ratings or data have been assigned or made available by the third parties.

This screening criteria is subject to change over time at BlackRocks discretion. BlackRock utilizes a proprietary sustainability scoring system, fundamental sector research and third-party ESG data in constructing the Funds portfolio. Fund management also selects and weights securities based on an issuers ability to manage the ESG risks to which its business is exposed, as determined by BlackRock. While Fund management considers ESG characteristics as well as climate risk exposure and climate opportunities, only one or two of these categories may be considered with respect to a particular investment or sector, and categories may be weighted differently according to the type of investment being considered. In addition, the Fund may gain indirect exposure (through, including but not limited to, derivatives and investments in other investment companies) to issuers with exposures that are inconsistent with the ESG-related criteria used by Fund management.

The Fund seeks to maintain certain ESG characteristics, climate risk exposure and climate opportunities relative to the Benchmark. Specifically, with respect to the Funds investments in certain sectors of fixed income instruments, the Fund generally seeks to invest in a portfolio that, in BlackRocks view, (i) has an aggregate ESG assessment that is better than that of the Benchmark, (ii) has an aggregate carbon emissions assessment that is lower than that of the Benchmark, and (iii) in the aggregate, includes issuers that BlackRock believes are better positioned to capture climate opportunities relative to the issuers in the Benchmark. Fund management makes such assessments based on BlackRocks ESG research, which includes due diligence of ESG risks and opportunities facing an issuer, as well as third-party ESG ratings.

The Fund may invest in other sectors that are not included in such assessments. The Fund may invest up to 30% of its net assets in securities of foreign issuers, of which 20% (as a percentage of the Funds net assets) may be in emerging markets issuers. Investments in U.S. dollar-denominated securities of foreign issuers, excluding issuers from emerging markets, are permitted beyond the 30% limit. This means that the Fund may invest in such U.S. dollar-denominated securities of foreign issuers without limit. The Fund may invest in various types of mortgage-backed securities. Mortgage-backed securities represent the right to receive a portion of principal and/or interest payments made on a pool of residential or commercial mortgage loans. Mortgage-backed securities frequently react differently to changes in interest rates than other fixed-income securities.

The Fund may also enter into reverse repurchase agreements and mortgage dollar rolls. The Fund may invest in fixed-income securities of any duration or maturity. Fixed-income securities frequently have redemption features that permit an issuer to repurchase the security from the Fund at certain times prior to maturity at a specified price, which is generally the amount due at maturity. In many cases, when interest rates go down, issuers redeem fixed-income securities that allow for redemption. When an issuer redeems fixed-income securities, the Fund may receive less than the market value of the securities prior to redemption. In addition, the Fund may have to invest the proceeds in new fixed-income securities with lower yields and therefore lose expected future income. The Fund may use derivatives, including, but not limited to, interest rate, total return and credit default swaps, options, futures, options on futures and swaps, for hedging purposes, as well as to increase the return on its portfolio investments.

Derivatives are financial instruments whose value is derived from another security or an index such as the Bloomberg U.S. Aggregate Bond Index or the CSFB High Yield Index. The Fund may also invest in credit-linked notes, credit-linked trust certificates, structured notes, or other instruments evidencing interests in special purpose vehicles, trusts, or other entities that hold or represent interests in fixed-income securities. The Fund may invest up to 20% of its net assets in fixed-income securities that are rated below investment grade by the Nationally Recognized Statistical Rating Organizations (NRSROs), including Moodys, S&P or Fitch or in unrated securities of equivalent credit quality. Split rated bonds will be considered to have the higher credit rating. The Fund may invest up to 15% of its net assets in collateralized debt obligations (CDOs), of which 10% (as a percentage of the Funds net assets) may be in collateralized loan obligations (CLOs).

CDOs are types of asset-backed securities. CLOs are ordinarily issued by a trust or other special purpose entity and are typically collateralized by a pool of loans, which may include, among others, domestic and non-U.S. senior secured loans, senior unsecured loans, and subordinate corporate loans, including loans that may be rated below investment grade or equivalent unrated loans, held by such issuer. The Fund may seek to provide exposure to the investment returns of real assets that trade in the commodity markets through investment in commodity-linked derivative instruments and investment vehicles that exclusively invest in precious metals, which are designed to provide this exposure without direct investment in physical commodities. The Fund may also gain exposure to commodity markets by investing up to 25% of its total assets in the Subsidiary, a wholly owned subsidiary of the Fund formed in the Cayman Islands, which invests primarily in commodity-related instruments.

The financial statements of the Subsidiary are consolidated with the Fund's financial statements in the Fund's Annual and Semi-Annual Financial Statements and Additional Information. The Fund's Annual and Semi-Annual Financial Statements and Additional Information are filed with the SEC on Form N-CSR and are provided without charge upon request as indicated on the back cover of this prospectus.

C000230844 Holdings

Top 10 holdings of BlackRock Sustainable Total Return Fund by percentage of net assets, from the fund's latest SEC N-PORT filing.

View all C000230844 holdings

C000230844 Portfolio Allocation

Asset-class allocation of BlackRock Sustainable Total Return Fund by percentage of net assets, from the latest SEC N-PORT filing.

C000230844 Performance

Total returns for C000230844 (as of 2026-10-01), from SEC filings.

C000230844 Risk Information

Risk metrics for C000230844, derived from monthly returns in SEC filings.

• 1-year volatility (annualised): 5.4%

C000230844 Costs and Fees

C000230844 costs about $76 per $10,000 invested per year in fund expenses.

• Net expense ratio: 0.76%
• Gross expense ratio: 1.98%
• Portfolio turnover: 832%
• Brokerage commissions: 2.47 bps of average net assets (SEC N-CEN)

C000230844 Cashflows

Over the 12 months to 2025-06, BlackRock Sustainable Total Return Fund had net inflows of $1.49M, from monthly SEC N-PORT filings.

C000230844 Debt Constituents

Largest debt holdings of BlackRock Sustainable Total Return Fund by percentage of net assets, from the latest SEC N-PORT filing.

C000230844 Prospectus and SEC Filings

Official BlackRock Sustainable Total Return Fund filings on SEC EDGAR — prospectus, portfolio holdings and annual reports.

• Prospectus (485BPOS) — filed 2025-01-27
• Prospectus (485BPOS) — filed 2024-01-25
• Prospectus (485BPOS) — filed 2023-01-26
• Portfolio holdings (N-PORT) — filed 2025-08-28
• Portfolio holdings (N-PORT) — filed 2025-05-27
• Portfolio holdings (N-PORT) — filed 2025-02-27
• Annual census (N-CEN) — filed 2024-12-10
• Annual census (N-CEN) — filed 2023-12-11

Related Funds

Other Long Securitized (MBS/ABS/CMBS) Bond funds tracked on ABC INVEST:

• PIMCO Income Fund (PONAX)
• Bridge Builder Core Plus Bond Fund (BBCPX)
• iShares MBS ETF (MBB)
• Guggenheim Total Return Bond Fund (GIBAX)
• Janus Henderson AAA CLO ETF (JAAA)

Data Sources

ABC INVEST compiles this page from public filings made to the U.S. Securities and Exchange Commission (SEC) through EDGAR: portfolio holdings and monthly cashflows from Form N-PORT, expenses and returns from fund prospectuses (Form 485BPOS) and the SEC DERA Risk/Return Summary data sets, annual data from Form N-CEN, and shareholder reports from Form N-CSR.