0000844779 bf1:C000237396Member 2022-11-03 2025-12-31 0000844779 bf1:S000077205Member bf1:C000237396Member 2026-04-30 2026-04-30 0000844779 bf1:S000077205Member bf1:CreditRisksMember 2026-04-30 2026-04-30 0000844779 bf1:S000077205Member bf1:IncomeRiskMember 2026-04-30 2026-04-30 0000844779 bf1:S000077205Member bf1:InterestRateRisksMember 2026-04-30 2026-04-30 0000844779 bf1:S000077205Member bf1:LargeShareholderAndLargeScaleRedemptionRiskMember 2026-04-30 2026-04-30 0000844779 bf1:S000077205Member bf1:MarketRiskAndSelectionRiskMember 2026-04-30 2026-04-30 0000844779 bf1:S000077205Member bf1:OperationalAndTechnologyRisksMember 2026-04-30 2026-04-30 0000844779 bf1:S000077205Member bf1:RepurchaseAgreementsRiskMember 2026-04-30 2026-04-30 0000844779 bf1:S000077205Member oef:RiskLoseMoneyMember 2026-04-30 2026-04-30 0000844779 bf1:S000077205Member oef:RiskMoneyMarketFundMayNotPreserveDollarMember 2026-04-30 2026-04-30 0000844779 bf1:S000077205Member oef:RiskMoneyMarketFundSponsorMayNotProvideSupportMember 2026-04-30 2026-04-30 0000844779 bf1:S000077205Member oef:RiskNotInsuredDepositoryInstitutionMember 2026-04-30 2026-04-30 0000844779 bf1:S000077205Member bf1:RiskOfInvestingInTheUnitedStatesMember 2026-04-30 2026-04-30 0000844779 bf1:S000077205Member bf1:ShareholderPurchaseRedemptionRiskMember 2026-04-30 2026-04-30 0000844779 bf1:S000077205Member bf1:StableNetAssetValueRiskMember 2026-04-30 2026-04-30 0000844779 bf1:S000077205Member bf1:TreasuryObligationsRiskMember 2026-04-30 2026-04-30 0000844779 bf1:S000077205Member bf1:WhenIssuedAndDelayedDeliverySecuritiesAndForwardCommitmentsRiskMember 2026-04-30 2026-04-30 0000844779 2026-04-30 2026-04-30 0000844779 bf1:S000077205Member bf1:C000237396Member 2023-01-01 2023-12-31 0000844779 bf1:S000077205Member bf1:C000237396Member 2024-01-01 2024-12-31 0000844779 bf1:C000237396Member 2025-01-01 2025-12-31 0000844779 bf1:S000077205Member bf1:C000237396Member 2025-01-01 2025-12-31 0000844779 bf1:S000077205Member 2026-04-30 2026-04-30 iso4217:USD pure 0000844779 false 485BPOS 2026-04-30 0.0498 0.0525 0.0425 N-1A BLACKROCK FUNDS 2026-08-28 Fund Overview Key Facts About Circle Reserve Fund Investment Objective <div style="margin-top: 6pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">The investment objective of Circle Reserve Fund (the “Fund”), a series of BlackRock Funds</span><span style="color: #000000; font-family: arial; font-size: 5pt; position: relative; top: -3.25pt;">SM</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> (the “Trust”), is to seek </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">current income as is consistent with liquidity and stability of principal.</span></div> Fees and Expenses of the Fund <div style="margin-top: 6pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">This table describes the fees and expenses that you may pay if you buy, hold and sell shares of the Fund. Amounts in </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">the table are rounded to the nearest basis point, which in some cases may be </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">“</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">0.00.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">”</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> More information about these </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">fees and expenses is available in the “Details About the Share Class” section on page 14 of the Fund’s prospectus </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">and in the “Purchase of Shares” section on page II-33 of Part II of the Fund’s Statement of Additional Information.</span><span style="color: #000000; font-family: arial; font-size: 1pt; line-height: 0.93pt;"> </span></div> Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment) 0.0014 0 0.0006 0.0020 -0.0003 0.0017 June 30, 2028 Example: <div style="line-height: 10.695pt; margin-top: 0.0pt; text-align: left;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">or lower, based on these assumptions your costs would be:</span><span style="color: #000000; font-family: arial; font-size: 1pt; line-height: 0.93pt;"> </span></div> 17 61 110 252 Principal Investment Strategies of the Fund <div style="margin-top: 6pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">The Fund invests 100% of its total assets in U.S. Treasury bills, notes and other obligations issued or guaranteed as </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">to principal and interest by the U.S. Treasury (collectively, “Treasury Instruments”) with a maturity of 93 days or less, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">cash, and overnight repurchase agreements secured by Treasury Instruments and cash. The Fund’s portfolio will have </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">a dollar-weighted average maturity of 60 days or less and a dollar-weighted average life of 120 days or less. The Fund </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">may transact in securities on a when-issued, delayed delivery or forward commitment basis.</span></div> <div style="margin-top: 6pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">The securities purchased by the Fund are subject to the quality, diversification, and other requirements of Rule 2a-7 </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">under the Investment Company Act of 1940, as amended (the “Investment Company Act”), and other rules of the Securities and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Exchange Commission.</span></div> You could lose money by investing in the Fund. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it cannot guarantee it will do so. An investment in the Fund is not a bank account and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund’s sponsor is not required to reimburse the Fund for losses, and you should not expect that the sponsor will provide financial support to the Fund at any time, including during periods of market stress. <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.0pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Interest Rate Risk </span><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">—</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">In general, the market price of debt securities with longer maturities will go up or down more in response to changes </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">in interest rates than the market price of shorter-term securities. Due to fluctuations in interest rates, the market </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">value of such securities may vary during the period shareholders own shares of the Fund. Very low or negative </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">interest rates may magnify interest rate risk. During periods of very low or negative interest rates, the Fund may be </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">unable to maintain positive returns or pay dividends to Fund shareholders. The Fund may be subject to a greater </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">risk of rising interest rates during a period of low interest rates. Changing interest rates may have unpredictable </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">effects on markets, may result in heightened market volatility and may detract from the Fund’s ability to achieve its </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">investment objective.</span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Treasury Obligations Risk </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">— Direct obligations of the U.S. Treasury have historically involved little risk of loss of </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">vary during the period shareholders own shares of the Fund. In addition, notwithstanding that U.S. Treasury </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">obligations are backed by the full faith and credit of the United States, circumstances could arise that could prevent </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">the timely payment of interest or principal, such as reaching the legislative “debt ceiling.” Such non-payment could </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">result in losses to the Fund and substantial negative consequences for the U.S. economy and the global financial </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">system.</span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Repurchase Agreements Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — If the other party to a repurchase agreement defaults on its obligation under the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">agreement, the Fund may suffer delays and incur costs or lose money in exercising its rights under the agreement. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">If the seller fails to repurchase the security and the market value of the security declines, the Fund may lose money.</span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Shareholder Purchase/Redemption Risk </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">— Shares of the Fund are held by Circle Internet Financial, LLC and Circle </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Internet Financial Europe SAS (collectively, “Circle”) as a portion of the reserves associated with Circle’s issuance </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">of stablecoins to customers. The assets of the Fund are expected to fluctuate depending on the creation (mining) of </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">additional stablecoins or the redemption (burning) of such coins. Stablecoins may face periods of uncertainty </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">resulting in the potential for rapid requests by Circle for redemption of the Fund’s shares.</span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Credit Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — Credit risk refers to the possibility that the issuer of a debt security (i.e., the borrower) will be unable </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">or unwilling to make timely payments of interest and principal when due or otherwise honor their obligations. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also affect the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">value of the Fund’s investment in that issuer.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Income Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — Income risk is the risk that the Fund’s yield will vary as short-term securities in its portfolio mature </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">and the proceeds are reinvested in securities with different interest rates.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Large Shareholder and Large-Scale Redemption Risk </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">— </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Certain shareholders may from time to time own or manage a </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">substantial amount of Fund shares, including funds or accounts over which the Fund’s adviser has discretion, or </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">may invest in the Fund and hold its investment for a limited period of time. There can be no assurance that any </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">large shareholder or large group of shareholders would not redeem their investment or that the size of the Fund </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">would be maintained. Redemptions of a large number of Fund shares by these shareholders may adversely affect </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">the Fund’s liquidity and net assets. These redemptions may force the Fund to sell portfolio securities to meet </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">redemption requests when it might not otherwise do so, which may negatively impact the Fund. In addition, large </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">redemptions can result in the Fund’s current expenses being allocated over a smaller asset base, which generally </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">could result in an increase in the Fund’s expense ratio.</span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Market Risk and Selection Risk </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">— Market risk is the risk that one or more markets in which the Fund invests will </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">go down in value, including the possibility that the markets will go down sharply and unpredictably. Securities or </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">other investments held by the Fund may underperform the markets, the relevant indices or benchmarks, or the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">securities selected by other funds with similar investment objectives and investment strategies, or may otherwise </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">fail to perform as intended. The value of a security or other asset may decline due to changes in general market </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">conditions, economic trends or events that are not specifically related to the issuer of the security or other asset, or </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">factors that affect a particular issuer or issuers, exchange, country, group of countries, region, market, industry, </span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div style="line-height: 10.695pt; margin-left: 12pt; text-align: left;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">group of industries, sector or asset class. The success of the Fund’s activities could be affected by interest rates, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">availability of credit, inflation rates, economic uncertainty, changes in laws, tariffs and trade barriers, supply chain </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">disruptions, economic sanctions, currency exchange controls, and local, regional or global events such as war, acts </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">of terrorism, natural and environmental disasters, the spread of infectious illness or other public health issues, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">recessions, or other events.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Recent policy initiatives undertaken by the U.S. government have the potential to impact international relations, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">trade agreements and the overall regulatory environment in ways that could create uncertainty and instability in </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">domestic and global markets, and could adversely affect the investment performance of the Fund. In particular, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">actions taken by the U.S. government in respect of international trade relations could lead to trade wars, increased </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">costs for imported goods, disruptions in supply chains, reduced foreign investment, and instability in regions where </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">the Fund invests.</span></div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Operational and Technology Risks </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">— The Fund is directly and indirectly susceptible to operational and technology </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">risks, including those related to human errors, processing errors, communication errors, systems failures, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">cybersecurity incidents, and the use of artificial intelligence and machine learning (“AI”), which may result in losses </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">for the Fund and its shareholders or may impair the Fund’s operations. While the Fund’s service providers are </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">required to have appropriate operational, information security and cybersecurity risk management policies and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">procedures, their methods of risk management may differ from those of the Fund. Operational and technology risks </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">for the issuers in which the Fund invests could also result in material adverse consequences for such issuers and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">may cause the Fund’s investments in such issuers to lose value.</span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Risk of Investing in the United States</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — Certain changes in the U.S. economy, such as when the U.S. economy </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">weakens or when its financial markets decline, may have an adverse effect on the securities to which the Fund has </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">exposure.</span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Stable Net Asset Value Risk </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">— The Fund may not be able to maintain a stable net asset value (</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">“</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">NAV</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">”</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">) of $1.00 per </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">share at all times. If the Fund fails to maintain a stable NAV (or if there is a perceived threat of such a failure), the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Fund, along with other money market funds, could be subject to increased redemption activity.</span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">When-Issued and Delayed Delivery Securities and Forward Commitments Risk </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">— When-issued and delayed </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">delivery securities and forward commitments involve the risk that the security the Fund buys will lose value prior to </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">its delivery. There also is the risk that the security will not be issued or that the other party to the transaction will </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">not meet its obligation. If this occurs, the Fund may lose both the investment opportunity for the assets it set aside </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">to pay for the security and any gain in the security’s price.</span></div> </div> <div style="clear: both; position: relative;"> </div> </div> Performance Information <div style="margin-top: 6pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">The information shows you how the Fund’s performance has varied year by year and provides some indication of the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">risks of investing in the Fund. To the extent that dividends and distributions have been paid by the Fund, the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">performance information for the Fund in the chart and table assumes reinvestment of the dividends and distributions. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">As with all such investments, past performance is not an indication of future results. The table includes all applicable </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">fees. If BlackRock and its affiliates had not waived or reimbursed certain Fund expenses during these periods, the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Fund’s returns would have been lower. The Fund is a money market fund managed pursuant to the requirements of </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Rule 2a-7 under the Investment Company Act. Updated information on the Fund’s performance can be obtained by </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">visiting </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">www.blackrock.com/cash</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> or can be obtained by phone at </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">(800) 441-7450</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">.</span></div> The information shows you how the Fund’s performance has varied year by year and provides some indication of the risks of investing in the Fund. As with all such investments, past performance is not an indication of future results. www.blackrock.com/cash (800) 441-7450 Institutional Shares ANNUAL TOTAL RETURNS Circle Reserve Fund As of 12/31 <div style="margin-top: 6pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">During the periods shown in the bar chart, the highest return for a quarter was 1.34% (quarter ended </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">December 31, 2023) and the lowest return for a quarter was 0.99% (quarter ended December 31, 2025). The year-to-date</span> <span style="color: #000000; font-family: arial; font-size: 9.30pt;">return as of June 30, 2026 was 1.79%.</span><span style="color: #000000; font-family: arial; font-size: 1pt; line-height: 0.93pt;"> </span></div> highest return 0.0134 2023-12-31 lowest return 0.0099 2025-12-31 year-to-datereturn 2026-06-30 0.0179 For the periods ended 12/31/25Average Annual Total Returns 2022-11-03 0.0425 0.0479 <div style="margin-top: 12pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">To obtain the Fund’s current 7-day yield, call </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">(800) 441-7450</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> or visit the Fund’s website at www.blackrock.com/cash.</span></div> (800) 441-7450 As described in the “Management of the Fund” section of the Fund’s prospectus beginning on page 18, BlackRock Advisors, LLC (“BlackRock”), the Fund’s investment manager, has contractually agreed to waive and/or reimburse fees or expenses in order to limit Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements (excluding Dividend Expense, Interest Expense, Acquired Fund Fees and Expenses and certain other Fund expenses) to 0.17% of average daily net assets through June 30, 2028. The contractual agreement may be terminated upon 90 days’ notice by a majority of the non-interested trustees of the Trust or by a vote of a majority of the outstanding voting securities of the Fund.